Merged to latest master

56 files changed, 3010 insertions, 890 deletions

diff --git a/rest_framework/__init__.py b/rest_framework/__init__.py
index fd176603..1d25ee7f 100644
--- a/rest_framework/__init__.py
+++ b/rest_framework/__init__.py
@@ -1,3 +1,3 @@
-__version__ = '2.1.2'
+__version__ = '2.1.15'
 
 VERSION = __version__  # synonym
diff --git a/rest_framework/authtoken/migrations/0001_initial.py b/rest_framework/authtoken/migrations/0001_initial.py
index 9d750381..f4e052e4 100644
--- a/rest_framework/authtoken/migrations/0001_initial.py
+++ b/rest_framework/authtoken/migrations/0001_initial.py
@@ -5,13 +5,21 @@ from south.v2 import SchemaMigration
 from django.db import models
 
 
+try:
+    from django.contrib.auth import get_user_model
+except ImportError: # django < 1.5
+    from django.contrib.auth.models import User
+else:
+    User = get_user_model()
+
+
 class Migration(SchemaMigration):
 
     def forwards(self, orm):
         # Adding model 'Token'
         db.create_table('authtoken_token', (
             ('key', self.gf('django.db.models.fields.CharField')(max_length=40, primary_key=True)),
-            ('user', self.gf('django.db.models.fields.related.OneToOneField')(related_name='auth_token', unique=True, to=orm['auth.User'])),
+            ('user', self.gf('django.db.models.fields.related.OneToOneField')(related_name='auth_token', unique=True, to=orm['%s.%s' % (User._meta.app_label, User._meta.object_name)])),
             ('created', self.gf('django.db.models.fields.DateTimeField')(auto_now_add=True, blank=True)),
         ))
         db.send_create_signal('authtoken', ['Token'])
@@ -36,7 +44,7 @@ class Migration(SchemaMigration):
             'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
             'name': ('django.db.models.fields.CharField', [], {'max_length': '50'})
         },
-        'auth.user': {
+        "%s.%s" % (User._meta.app_label, User._meta.module_name): {
             'Meta': {'object_name': 'User'},
             'date_joined': ('django.db.models.fields.DateTimeField', [], {'default': 'datetime.datetime.now'}),
             'email': ('django.db.models.fields.EmailField', [], {'max_length': '75', 'blank': 'True'}),
@@ -56,7 +64,7 @@ class Migration(SchemaMigration):
             'Meta': {'object_name': 'Token'},
             'created': ('django.db.models.fields.DateTimeField', [], {'auto_now_add': 'True', 'blank': 'True'}),
             'key': ('django.db.models.fields.CharField', [], {'max_length': '40', 'primary_key': 'True'}),
-            'user': ('django.db.models.fields.related.OneToOneField', [], {'related_name': "'auth_token'", 'unique': 'True', 'to': "orm['auth.User']"})
+            'user': ('django.db.models.fields.related.OneToOneField', [], {'related_name': "'auth_token'", 'unique': 'True', 'to': "orm['%s.%s']" % (User._meta.app_label, User._meta.object_name)})
         },
         'contenttypes.contenttype': {
             'Meta': {'ordering': "('name',)", 'unique_together': "(('app_label', 'model'),)", 'object_name': 'ContentType', 'db_table': "'django_content_type'"},
diff --git a/rest_framework/authtoken/models.py b/rest_framework/authtoken/models.py
index 5b3071aa..4da2aa62 100644
--- a/rest_framework/authtoken/models.py
+++ b/rest_framework/authtoken/models.py
@@ -1,6 +1,7 @@
 import uuid
 import hmac
 from hashlib import sha1
+from rest_framework.compat import User
 from django.db import models
 
 
@@ -9,7 +10,7 @@ class Token(models.Model):
     The default authorization token model.
     """
     key = models.CharField(max_length=40, primary_key=True)
-    user = models.OneToOneField('auth.User', related_name='auth_token')
+    user = models.OneToOneField(User, related_name='auth_token')
     created = models.DateTimeField(auto_now_add=True)
 
     def save(self, *args, **kwargs):
diff --git a/rest_framework/authtoken/serializers.py b/rest_framework/authtoken/serializers.py
new file mode 100644
index 00000000..60a3740e
--- /dev/null
+++ b/rest_framework/authtoken/serializers.py
@@ -0,0 +1,24 @@
+from django.contrib.auth import authenticate
+from rest_framework import serializers
+
+
+class AuthTokenSerializer(serializers.Serializer):
+    username = serializers.CharField()
+    password = serializers.CharField()
+
+    def validate(self, attrs):
+        username = attrs.get('username')
+        password = attrs.get('password')
+
+        if username and password:
+            user = authenticate(username=username, password=password)
+
+            if user:
+                if not user.is_active:
+                    raise serializers.ValidationError('User account is disabled.')
+                attrs['user'] = user
+                return attrs
+            else:
+                raise serializers.ValidationError('Unable to login with provided credentials.')
+        else:
+            raise serializers.ValidationError('Must include "username" and "password"')
diff --git a/rest_framework/authtoken/views.py b/rest_framework/authtoken/views.py
index e69de29b..d318c723 100644
--- a/rest_framework/authtoken/views.py
+++ b/rest_framework/authtoken/views.py
@@ -0,0 +1,25 @@
+from rest_framework.views import APIView
+from rest_framework import status
+from rest_framework import parsers
+from rest_framework import renderers
+from rest_framework.response import Response
+from rest_framework.authtoken.models import Token
+from rest_framework.authtoken.serializers import AuthTokenSerializer
+
+
+class ObtainAuthToken(APIView):
+    throttle_classes = ()
+    permission_classes = ()
+    parser_classes = (parsers.FormParser, parsers.MultiPartParser, parsers.JSONParser,)
+    renderer_classes = (renderers.JSONRenderer,)
+    model = Token
+
+    def post(self, request):
+        serializer = AuthTokenSerializer(data=request.DATA)
+        if serializer.is_valid():
+            token, created = Token.objects.get_or_create(user=serializer.object['user'])
+            return Response({'token': token.key})
+        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
+
+
+obtain_auth_token = ObtainAuthToken.as_view()
diff --git a/rest_framework/compat.py b/rest_framework/compat.py
index 02e50604..5508f6c0 100644
--- a/rest_framework/compat.py
+++ b/rest_framework/compat.py
@@ -1,10 +1,16 @@
 """
 The `compat` module provides support for backwards compatibility with older
-versions of django/python, and compatbility wrappers around optional packages.
+versions of django/python, and compatibility wrappers around optional packages.
 """
 # flake8: noqa
 import django
 
+# location of patterns, url, include changes in 1.4 onwards
+try:
+    from django.conf.urls import patterns, url, include
+except:
+    from django.conf.urls.defaults import patterns, url, include
+
 # django-filter is optional
 try:
     import django_filters
@@ -19,6 +25,16 @@ except ImportError:
     import StringIO
 
 
+# Try to import PIL in either of the two ways it can end up installed.
+try:
+    from PIL import Image
+except ImportError:
+    try:
+        import Image
+    except ImportError:
+        Image = None
+
+
 def get_concrete_model(model_cls):
     try:
         return model_cls._meta.concrete_model
@@ -27,6 +43,20 @@ def get_concrete_model(model_cls):
         return model_cls
 
 
+# Django 1.5 add support for custom auth user model
+if django.VERSION >= (1, 5):
+    from django.conf import settings
+    if hasattr(settings, 'AUTH_USER_MODEL'):
+        User = settings.AUTH_USER_MODEL
+    else:
+        from django.contrib.auth.models import User
+else:
+    try:
+        from django.contrib.auth.models import User
+    except ImportError:
+        raise ImportError(u"User model is not to be found.")
+
+
 # First implementation of Django class-based views did not include head method
 # in base View class - https://code.djangoproject.com/ticket/15668
 if django.VERSION >= (1, 4):
@@ -66,6 +96,12 @@ else:
             update_wrapper(view, cls.dispatch, assigned=())
             return view
 
+# Taken from @markotibold's attempt at supporting PATCH.
+# https://github.com/markotibold/django-rest-framework/tree/patch
+http_method_names = set(View.http_method_names)
+http_method_names.add('patch')
+View.http_method_names = list(http_method_names)  # PATCH method is not implemented by Django
+
 # PUT, DELETE do not require CSRF until 1.4.  They should.  Make it better.
 if django.VERSION >= (1, 4):
     from django.middleware.csrf import CsrfViewMiddleware
@@ -340,7 +376,7 @@ try:
         """
 
         extensions = ['headerid(level=2)']
-        safe_mode = False,
+        safe_mode = False
         md = markdown.Markdown(extensions=extensions, safe_mode=safe_mode)
         return md.convert(text)
 
diff --git a/rest_framework/decorators.py b/rest_framework/decorators.py
index a231f191..1b710a03 100644
--- a/rest_framework/decorators.py
+++ b/rest_framework/decorators.py
@@ -17,7 +17,7 @@ def api_view(http_method_names):
         )
 
         # Note, the above allows us to set the docstring.
-        # It is the equivelent of:
+        # It is the equivalent of:
         #
         #     class WrappedAPIView(APIView):
         #         pass
diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index a4e29a30..998911e1 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -1,20 +1,20 @@
 import copy
 import datetime
 import inspect
+import re
 import warnings
 
+from io import BytesIO
+
 from django.core import validators
-from django.core.exceptions import ObjectDoesNotExist, ValidationError
-from django.core.urlresolvers import resolve, get_script_prefix
+from django.core.exceptions import ValidationError
 from django.conf import settings
+from django import forms
 from django.forms import widgets
-from django.forms.models import ModelChoiceIterator
 from django.utils.encoding import is_protected_type, smart_unicode
 from django.utils.translation import ugettext_lazy as _
-from rest_framework.reverse import reverse
 from rest_framework.compat import parse_date, parse_datetime
 from rest_framework.compat import timezone
-from urlparse import urlparse
 
 
 def is_simple_callable(obj):
@@ -28,9 +28,12 @@ def is_simple_callable(obj):
 
 
 class Field(object):
+    read_only = True
     creation_counter = 0
     empty = ''
     type_name = None
+    _use_files = None
+    form_field_class = forms.CharField
 
     def __init__(self, source=None):
         self.parent = None
@@ -50,8 +53,10 @@ class Field(object):
         self.parent = parent
         self.root = parent.root or parent
         self.context = self.root.context
+        if self.root.partial:
+            self.required = False
 
-    def field_from_native(self, data, field_name, into):
+    def field_from_native(self, data, files, field_name, into):
         """
         Given a dictionary and a field name, updates the dictionary `into`,
         with the field and it's deserialized value.
@@ -125,7 +130,7 @@ class WritableField(Field):
         if required is None:
             self.required = not(read_only)
         else:
-            assert not read_only, "Cannot set required=True and read_only=True"
+            assert not (read_only and required), "Cannot set required=True and read_only=True"
             self.required = required
 
         messages = {}
@@ -166,7 +171,7 @@ class WritableField(Field):
         if errors:
             raise ValidationError(errors)
 
-    def field_from_native(self, data, field_name, into):
+    def field_from_native(self, data, files, field_name, into):
         """
         Given a dictionary and a field name, updates the dictionary `into`,
         with the field and it's deserialized value.
@@ -175,9 +180,14 @@ class WritableField(Field):
             return
 
         try:
-            native = data[field_name]
+            if self._use_files:
+                files = files or {}
+                native = files[field_name]
+            else:
+                native = data[field_name]
         except KeyError:
-            if self.default is not None:
+            if self.default is not None and not self.root.partial:
+                # Note: partial updates shouldn't set defaults
                 native = self.default
             else:
                 if self.required:
@@ -209,8 +219,19 @@ class ModelField(WritableField):
             self.model_field = kwargs.pop('model_field')
         except:
             raise ValueError("ModelField requires 'model_field' kwarg")
+
+        self.min_length = kwargs.pop('min_length',
+                            getattr(self.model_field, 'min_length', None))
+        self.max_length = kwargs.pop('max_length',
+                            getattr(self.model_field, 'max_length', None))
+
         super(ModelField, self).__init__(*args, **kwargs)
 
+        if self.min_length is not None:
+            self.validators.append(validators.MinLengthValidator(self.min_length))
+        if self.max_length is not None:
+            self.validators.append(validators.MaxLengthValidator(self.max_length))
+
     def from_native(self, value):
         rel = getattr(self.model_field, "rel", None)
         if rel is not None:
@@ -229,428 +250,12 @@ class ModelField(WritableField):
             "type": self.model_field.get_internal_type()
         }
 
-##### Relational fields #####
-
-
-# Not actually Writable, but subclasses may need to be.
-class RelatedField(WritableField):
-    """
-    Base class for related model fields.
-
-    If not overridden, this represents a to-one relationship, using the unicode
-    representation of the target.
-    """
-    widget = widgets.Select
-    cache_choices = False
-    empty_label = None
-    default_read_only = True  # TODO: Remove this
-
-    def __init__(self, *args, **kwargs):
-        self.queryset = kwargs.pop('queryset', None)
-        super(RelatedField, self).__init__(*args, **kwargs)
-        self.read_only = kwargs.pop('read_only', self.default_read_only)
-
-    def initialize(self, parent, field_name):
-        super(RelatedField, self).initialize(parent, field_name)
-        if self.queryset is None and not self.read_only:
-            try:
-                manager = getattr(self.parent.opts.model, self.source or field_name)
-                if hasattr(manager, 'related'):  # Forward
-                    self.queryset = manager.related.model._default_manager.all()
-                else:  # Reverse
-                    self.queryset = manager.field.rel.to._default_manager.all()
-            except:
-                raise
-                msg = ('Serializer related fields must include a `queryset`' +
-                       ' argument or set `read_only=True')
-                raise Exception(msg)
-
-    ### We need this stuff to make form choices work...
-
-    # def __deepcopy__(self, memo):
-    #     result = super(RelatedField, self).__deepcopy__(memo)
-    #     result.queryset = result.queryset
-    #     return result
-
-    def prepare_value(self, obj):
-        return self.to_native(obj)
-
-    def label_from_instance(self, obj):
-        """
-        Return a readable representation for use with eg. select widgets.
-        """
-        desc = smart_unicode(obj)
-        ident = smart_unicode(self.to_native(obj))
-        if desc == ident:
-            return desc
-        return "%s - %s" % (desc, ident)
-
-    def _get_queryset(self):
-        return self._queryset
-
-    def _set_queryset(self, queryset):
-        self._queryset = queryset
-        self.widget.choices = self.choices
-
-    queryset = property(_get_queryset, _set_queryset)
-
-    def _get_choices(self):
-        # If self._choices is set, then somebody must have manually set
-        # the property self.choices. In this case, just return self._choices.
-        if hasattr(self, '_choices'):
-            return self._choices
-
-        # Otherwise, execute the QuerySet in self.queryset to determine the
-        # choices dynamically. Return a fresh ModelChoiceIterator that has not been
-        # consumed. Note that we're instantiating a new ModelChoiceIterator *each*
-        # time _get_choices() is called (and, thus, each time self.choices is
-        # accessed) so that we can ensure the QuerySet has not been consumed. This
-        # construct might look complicated but it allows for lazy evaluation of
-        # the queryset.
-        return ModelChoiceIterator(self)
-
-    def _set_choices(self, value):
-        # Setting choices also sets the choices on the widget.
-        # choices can be any iterable, but we call list() on it because
-        # it will be consumed more than once.
-        self._choices = self.widget.choices = list(value)
-
-    choices = property(_get_choices, _set_choices)
-
-    ### Regular serializier stuff...
-
-    def field_to_native(self, obj, field_name):
-        value = getattr(obj, self.source or field_name)
-        return self.to_native(value)
-
-    def field_from_native(self, data, field_name, into):
-        if self.read_only:
-            return
-
-        value = data.get(field_name)
-        into[(self.source or field_name)] = self.from_native(value)
-
-
-class ManyRelatedMixin(object):
-    """
-    Mixin to convert a related field to a many related field.
-    """
-    widget = widgets.SelectMultiple
-
-    def field_to_native(self, obj, field_name):
-        value = getattr(obj, self.source or field_name)
-        return [self.to_native(item) for item in value.all()]
-
-    def field_from_native(self, data, field_name, into):
-        if self.read_only:
-            return
-
-        try:
-            # Form data
-            value = data.getlist(self.source or field_name)
-        except:
-            # Non-form data
-            value = data.get(self.source or field_name)
-        else:
-            if value == ['']:
-                value = []
-        into[field_name] = [self.from_native(item) for item in value]
-
-
-class ManyRelatedField(ManyRelatedMixin, RelatedField):
-    """
-    Base class for related model managers.
-
-    If not overridden, this represents a to-many relationship, using the unicode
-    representations of the target, and is read-only.
-    """
-    pass
-
-
-### PrimaryKey relationships
-
-class PrimaryKeyRelatedField(RelatedField):
-    """
-    Represents a to-one relationship as a pk value.
-    """
-    default_read_only = False
-
-    # TODO: Remove these field hacks...
-    def prepare_value(self, obj):
-        return self.to_native(obj.pk)
-
-    def label_from_instance(self, obj):
-        """
-        Return a readable representation for use with eg. select widgets.
-        """
-        desc = smart_unicode(obj)
-        ident = smart_unicode(self.to_native(obj.pk))
-        if desc == ident:
-            return desc
-        return "%s - %s" % (desc, ident)
-
-    # TODO: Possibly change this to just take `obj`, through prob less performant
-    def to_native(self, pk):
-        return pk
-
-    def from_native(self, data):
-        if self.queryset is None:
-            raise Exception('Writable related fields must include a `queryset` argument')
-
-        try:
-            return self.queryset.get(pk=data)
-        except ObjectDoesNotExist:
-            msg = "Invalid pk '%s' - object does not exist." % smart_unicode(data)
-            raise ValidationError(msg)
-
-    def field_to_native(self, obj, field_name):
-        try:
-            # Prefer obj.serializable_value for performance reasons
-            pk = obj.serializable_value(self.source or field_name)
-        except AttributeError:
-            # RelatedObject (reverse relationship)
-            obj = getattr(obj, self.source or field_name)
-            return self.to_native(obj.pk)
-        # Forward relationship
-        return self.to_native(pk)
-
-
-class ManyPrimaryKeyRelatedField(ManyRelatedField):
-    """
-    Represents a to-many relationship as a pk value.
-    """
-    default_read_only = False
-
-    def prepare_value(self, obj):
-        return self.to_native(obj.pk)
-
-    def label_from_instance(self, obj):
-        """
-        Return a readable representation for use with eg. select widgets.
-        """
-        desc = smart_unicode(obj)
-        ident = smart_unicode(self.to_native(obj.pk))
-        if desc == ident:
-            return desc
-        return "%s - %s" % (desc, ident)
-
-    def to_native(self, pk):
-        return pk
-
-    def field_to_native(self, obj, field_name):
-        try:
-            # Prefer obj.serializable_value for performance reasons
-            queryset = obj.serializable_value(self.source or field_name)
-        except AttributeError:
-            # RelatedManager (reverse relationship)
-            queryset = getattr(obj, self.source or field_name)
-            return [self.to_native(item.pk) for item in queryset.all()]
-        # Forward relationship
-        return [self.to_native(item.pk) for item in queryset.all()]
-
-    def from_native(self, data):
-        if self.queryset is None:
-            raise Exception('Writable related fields must include a `queryset` argument')
-
-        try:
-            return self.queryset.get(pk=data)
-        except ObjectDoesNotExist:
-            msg = "Invalid pk '%s' - object does not exist." % smart_unicode(data)
-            raise ValidationError(msg)
-
-### Slug relationships
-
-
-class SlugRelatedField(RelatedField):
-    default_read_only = False
-
-    def __init__(self, *args, **kwargs):
-        self.slug_field = kwargs.pop('slug_field', None)
-        assert self.slug_field, 'slug_field is required'
-        super(SlugRelatedField, self).__init__(*args, **kwargs)
-
-    def to_native(self, obj):
-        return getattr(obj, self.slug_field)
-
-    def from_native(self, data):
-        if self.queryset is None:
-            raise Exception('Writable related fields must include a `queryset` argument')
-
-        try:
-            return self.queryset.get(**{self.slug_field: data})
-        except ObjectDoesNotExist:
-            raise ValidationError('Object with %s=%s does not exist.' %
-                                  (self.slug_field, unicode(data)))
-
-
-class ManySlugRelatedField(ManyRelatedMixin, SlugRelatedField):
-    pass
-
-
-### Hyperlinked relationships
-
-class HyperlinkedRelatedField(RelatedField):
-    """
-    Represents a to-one relationship, using hyperlinking.
-    """
-    pk_url_kwarg = 'pk'
-    slug_field = 'slug'
-    slug_url_kwarg = None  # Defaults to same as `slug_field` unless overridden
-    default_read_only = False
-
-    def __init__(self, *args, **kwargs):
-        try:
-            self.view_name = kwargs.pop('view_name')
-        except:
-            raise ValueError("Hyperlinked field requires 'view_name' kwarg")
-
-        self.slug_field = kwargs.pop('slug_field', self.slug_field)
-        default_slug_kwarg = self.slug_url_kwarg or self.slug_field
-        self.pk_url_kwarg = kwargs.pop('pk_url_kwarg', self.pk_url_kwarg)
-        self.slug_url_kwarg = kwargs.pop('slug_url_kwarg', default_slug_kwarg)
-
-        self.format = kwargs.pop('format', None)
-        super(HyperlinkedRelatedField, self).__init__(*args, **kwargs)
-
-    def get_slug_field(self):
-        """
-        Get the name of a slug field to be used to look up by slug.
-        """
-        return self.slug_field
-
-    def to_native(self, obj):
-        view_name = self.view_name
-        request = self.context.get('request', None)
-        format = self.format or self.context.get('format', None)
-        kwargs = {self.pk_url_kwarg: obj.pk}
-        try:
-            return reverse(view_name, kwargs=kwargs, request=request, format=format)
-        except:
-            pass
-
-        slug = getattr(obj, self.slug_field, None)
-
-        if not slug:
-            raise ValidationError('Could not resolve URL for field using view name "%s"' % view_name)
-
-        kwargs = {self.slug_url_kwarg: slug}
-        try:
-            return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
-        except:
-            pass
-
-        kwargs = {self.pk_url_kwarg: obj.pk, self.slug_url_kwarg: slug}
-        try:
-            return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
-        except:
-            pass
-
-        raise ValidationError('Could not resolve URL for field using view name "%s"', view_name)
-
-    def from_native(self, value):
-        # Convert URL -> model instance pk
-        # TODO: Use values_list
-        if self.queryset is None:
-            raise Exception('Writable related fields must include a `queryset` argument')
-
-        if value.startswith('http:') or value.startswith('https:'):
-            # If needed convert absolute URLs to relative path
-            value = urlparse(value).path
-            prefix = get_script_prefix()
-            if value.startswith(prefix):
-                value = '/' + value[len(prefix):]
-
-        try:
-            match = resolve(value)
-        except:
-            raise ValidationError('Invalid hyperlink - No URL match')
-
-        if match.url_name != self.view_name:
-            raise ValidationError('Invalid hyperlink - Incorrect URL match')
-
-        pk = match.kwargs.get(self.pk_url_kwarg, None)
-        slug = match.kwargs.get(self.slug_url_kwarg, None)
-
-        # Try explicit primary key.
-        if pk is not None:
-            queryset = self.queryset.filter(pk=pk)
-        # Next, try looking up by slug.
-        elif slug is not None:
-            slug_field = self.get_slug_field()
-            queryset = self.queryset.filter(**{slug_field: slug})
-        # If none of those are defined, it's an error.
-        else:
-            raise ValidationError('Invalid hyperlink')
-
-        try:
-            obj = queryset.get()
-        except ObjectDoesNotExist:
-            raise ValidationError('Invalid hyperlink - object does not exist.')
-        return obj
-
-
-class ManyHyperlinkedRelatedField(ManyRelatedMixin, HyperlinkedRelatedField):
-    """
-    Represents a to-many relationship, using hyperlinking.
-    """
-    pass
-
-
-class HyperlinkedIdentityField(Field):
-    """
-    Represents the instance, or a property on the instance, using hyperlinking.
-    """
-    pk_url_kwarg = 'pk'
-    slug_field = 'slug'
-    slug_url_kwarg = None  # Defaults to same as `slug_field` unless overridden
-
-    def __init__(self, *args, **kwargs):
-        # TODO: Make view_name mandatory, and have the
-        # HyperlinkedModelSerializer set it on-the-fly
-        self.view_name = kwargs.pop('view_name', None)
-        self.format = kwargs.pop('format', None)
-
-        self.slug_field = kwargs.pop('slug_field', self.slug_field)
-        default_slug_kwarg = self.slug_url_kwarg or self.slug_field
-        self.pk_url_kwarg = kwargs.pop('pk_url_kwarg', self.pk_url_kwarg)
-        self.slug_url_kwarg = kwargs.pop('slug_url_kwarg', default_slug_kwarg)
-
-        super(HyperlinkedIdentityField, self).__init__(*args, **kwargs)
-
-    def field_to_native(self, obj, field_name):
-        request = self.context.get('request', None)
-        format = self.format or self.context.get('format', None)
-        view_name = self.view_name or self.parent.opts.view_name
-        kwargs = {self.pk_url_kwarg: obj.pk}
-        try:
-            return reverse(view_name, kwargs=kwargs, request=request, format=format)
-        except:
-            pass
-
-        slug = getattr(obj, self.slug_field, None)
-
-        if not slug:
-            raise ValidationError('Could not resolve URL for field using view name "%s"' % view_name)
-
-        kwargs = {self.slug_url_kwarg: slug}
-        try:
-            return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
-        except:
-            pass
-
-        kwargs = {self.pk_url_kwarg: obj.pk, self.slug_url_kwarg: slug}
-        try:
-            return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
-        except:
-            pass
-
-        raise ValidationError('Could not resolve URL for field using view name "%s"', view_name)
-
 
 ##### Typed Fields #####
 
 class BooleanField(WritableField):
     type_name = 'BooleanField'
+    form_field_class = forms.BooleanField
     widget = widgets.CheckboxInput
     default_error_messages = {
         'invalid': _(u"'%s' value must be either True or False."),
@@ -663,15 +268,16 @@ class BooleanField(WritableField):
     default = False
 
     def from_native(self, value):
-        if value in ('t', 'True', '1'):
+        if value in ('true', 't', 'True', '1'):
             return True
-        if value in ('f', 'False', '0'):
+        if value in ('false', 'f', 'False', '0'):
             return False
         return bool(value)
 
 
 class CharField(WritableField):
     type_name = 'CharField'
+    form_field_class = forms.CharField
 
     def __init__(self, max_length=None, min_length=None, *args, **kwargs):
         self.max_length, self.min_length = max_length, min_length
@@ -697,8 +303,26 @@ class CharField(WritableField):
         return smart_unicode(value)
 
 
+class URLField(CharField):
+    type_name = 'URLField'
+
+    def __init__(self, **kwargs):
+        kwargs['max_length'] = kwargs.get('max_length', 200)
+        kwargs['validators'] = [validators.URLValidator()]
+        super(URLField, self).__init__(**kwargs)
+
+
+class SlugField(CharField):
+    type_name = 'SlugField'
+
+    def __init__(self, *args, **kwargs):
+        kwargs['max_length'] = kwargs.get('max_length', 50)
+        super(SlugField, self).__init__(*args, **kwargs)
+
+
 class ChoiceField(WritableField):
     type_name = 'ChoiceField'
+    form_field_class = forms.ChoiceField
     widget = widgets.Select
     default_error_messages = {
         'invalid_choice': _('Select a valid choice. %(value)s is not one of the available choices.'),
@@ -738,13 +362,14 @@ class ChoiceField(WritableField):
                     if value == smart_unicode(k2):
                         return True
             else:
-                if value == smart_unicode(k):
+                if value == smart_unicode(k) or value == k:
                     return True
         return False
 
 
 class EmailField(CharField):
     type_name = 'EmailField'
+    form_field_class = forms.EmailField
 
     default_error_messages = {
         'invalid': _('Enter a valid e-mail address.'),
@@ -765,8 +390,39 @@ class EmailField(CharField):
         return result
 
 
+class RegexField(CharField):
+    type_name = 'RegexField'
+    form_field_class = forms.RegexField
+
+    def __init__(self, regex, max_length=None, min_length=None, *args, **kwargs):
+        super(RegexField, self).__init__(max_length, min_length, *args, **kwargs)
+        self.regex = regex
+
+    def _get_regex(self):
+        return self._regex
+
+    def _set_regex(self, regex):
+        if isinstance(regex, basestring):
+            regex = re.compile(regex)
+        self._regex = regex
+        if hasattr(self, '_regex_validator') and self._regex_validator in self.validators:
+            self.validators.remove(self._regex_validator)
+        self._regex_validator = validators.RegexValidator(regex=regex)
+        self.validators.append(self._regex_validator)
+
+    regex = property(_get_regex, _set_regex)
+
+    def __deepcopy__(self, memo):
+        result = copy.copy(self)
+        memo[id(self)] = result
+        result.validators = self.validators[:]
+        return result
+
+
 class DateField(WritableField):
     type_name = 'DateField'
+    widget = widgets.DateInput
+    form_field_class = forms.DateField
 
     default_error_messages = {
         'invalid': _(u"'%s' value has an invalid date format. It must be "
@@ -804,6 +460,8 @@ class DateField(WritableField):
 
 class DateTimeField(WritableField):
     type_name = 'DateTimeField'
+    widget = widgets.DateTimeInput
+    form_field_class = forms.DateTimeField
 
     default_error_messages = {
         'invalid': _(u"'%s' value has an invalid format. It must be in "
@@ -858,6 +516,7 @@ class DateTimeField(WritableField):
 
 class IntegerField(WritableField):
     type_name = 'IntegerField'
+    form_field_class = forms.IntegerField
 
     default_error_messages = {
         'invalid': _('Enter a whole number.'),
@@ -887,6 +546,7 @@ class IntegerField(WritableField):
 
 class FloatField(WritableField):
     type_name = 'FloatField'
+    form_field_class = forms.FloatField
 
     default_error_messages = {
         'invalid': _("'%s' value must be a float."),
@@ -901,3 +561,108 @@ class FloatField(WritableField):
         except (TypeError, ValueError):
             msg = self.error_messages['invalid'] % value
             raise ValidationError(msg)
+
+
+class FileField(WritableField):
+    _use_files = True
+    type_name = 'FileField'
+    form_field_class = forms.FileField
+    widget = widgets.FileInput
+
+    default_error_messages = {
+        'invalid': _("No file was submitted. Check the encoding type on the form."),
+        'missing': _("No file was submitted."),
+        'empty': _("The submitted file is empty."),
+        'max_length': _('Ensure this filename has at most %(max)d characters (it has %(length)d).'),
+        'contradiction': _('Please either submit a file or check the clear checkbox, not both.')
+    }
+
+    def __init__(self, *args, **kwargs):
+        self.max_length = kwargs.pop('max_length', None)
+        self.allow_empty_file = kwargs.pop('allow_empty_file', False)
+        super(FileField, self).__init__(*args, **kwargs)
+
+    def from_native(self, data):
+        if data in validators.EMPTY_VALUES:
+            return None
+
+        # UploadedFile objects should have name and size attributes.
+        try:
+            file_name = data.name
+            file_size = data.size
+        except AttributeError:
+            raise ValidationError(self.error_messages['invalid'])
+
+        if self.max_length is not None and len(file_name) > self.max_length:
+            error_values = {'max': self.max_length, 'length': len(file_name)}
+            raise ValidationError(self.error_messages['max_length'] % error_values)
+        if not file_name:
+            raise ValidationError(self.error_messages['invalid'])
+        if not self.allow_empty_file and not file_size:
+            raise ValidationError(self.error_messages['empty'])
+
+        return data
+
+    def to_native(self, value):
+        return value.name
+
+
+class ImageField(FileField):
+    _use_files = True
+    form_field_class = forms.ImageField
+
+    default_error_messages = {
+        'invalid_image': _("Upload a valid image. The file you uploaded was either not an image or a corrupted image."),
+    }
+
+    def from_native(self, data):
+        """
+        Checks that the file-upload field data contains a valid image (GIF, JPG,
+        PNG, possibly others -- whatever the Python Imaging Library supports).
+        """
+        f = super(ImageField, self).from_native(data)
+        if f is None:
+            return None
+
+        from compat import Image
+        assert Image is not None, 'PIL must be installed for ImageField support'
+
+        # We need to get a file object for PIL. We might have a path or we might
+        # have to read the data into memory.
+        if hasattr(data, 'temporary_file_path'):
+            file = data.temporary_file_path()
+        else:
+            if hasattr(data, 'read'):
+                file = BytesIO(data.read())
+            else:
+                file = BytesIO(data['content'])
+
+        try:
+            # load() could spot a truncated JPEG, but it loads the entire
+            # image in memory, which is a DoS vector. See #3848 and #18520.
+            # verify() must be called immediately after the constructor.
+            Image.open(file).verify()
+        except ImportError:
+            # Under PyPy, it is possible to import PIL. However, the underlying
+            # _imaging C module isn't available, so an ImportError will be
+            # raised. Catch and re-raise.
+            raise
+        except Exception:  # Python Imaging Library doesn't recognize it as an image
+            raise ValidationError(self.error_messages['invalid_image'])
+        if hasattr(f, 'seek') and callable(f.seek):
+            f.seek(0)
+        return f
+
+
+class SerializerMethodField(Field):
+    """
+    A field that gets its value by calling a method on the serializer it's attached to.
+    """
+
+    def __init__(self, method_name):
+        self.method_name = method_name
+        super(SerializerMethodField, self).__init__()
+
+    def field_to_native(self, obj, field_name):
+        value = getattr(self.parent, self.method_name)(obj)
+        return self.to_native(value)
diff --git a/rest_framework/filters.py b/rest_framework/filters.py
index ccae4825..bcc87660 100644
--- a/rest_framework/filters.py
+++ b/rest_framework/filters.py
@@ -45,7 +45,7 @@ class DjangoFilterBackend(BaseFilterBackend):
             class AutoFilterSet(self.default_filter_set):
                 class Meta:
                     model = view_model
-                fields = filter_fields
+                    fields = filter_fields
             return AutoFilterSet
 
         return None
diff --git a/rest_framework/generics.py b/rest_framework/generics.py
index ebd06e45..19f2b704 100644
--- a/rest_framework/generics.py
+++ b/rest_framework/generics.py
@@ -14,6 +14,8 @@ class GenericAPIView(views.APIView):
     """
     Base class for all other generic views.
     """
+
+    model = None
     serializer_class = None
     model_serializer_class = api_settings.DEFAULT_MODEL_SERIALIZER_CLASS
 
@@ -30,8 +32,10 @@ class GenericAPIView(views.APIView):
     def get_serializer_class(self):
         """
         Return the class to use for the serializer.
-        Use `self.serializer_class`, falling back to constructing a
-        model serializer class from `self.model_serializer_class`
+
+        Defaults to using `self.serializer_class`, falls back to constructing a
+        model serializer class using `self.model_serializer_class`, with
+        `self.model` as the model.
         """
         serializer_class = self.serializer_class
 
@@ -43,12 +47,16 @@ class GenericAPIView(views.APIView):
 
         return serializer_class
 
-    def get_serializer(self, instance=None, data=None, files=None):
-        # TODO: add support for files
-        # TODO: add support for seperate serializer/deserializer
+    def get_serializer(self, instance=None, data=None,
+                       files=None, partial=False):
+        """
+        Return the serializer instance that should be used for validating and
+        deserializing input, and for serializing output.
+        """
         serializer_class = self.get_serializer_class()
         context = self.get_serializer_context()
-        return serializer_class(instance, data=data, context=context)
+        return serializer_class(instance, data=data, files=files,
+                                partial=partial, context=context)
 
 
 class MultipleObjectAPIView(MultipleObjectMixin, GenericAPIView):
@@ -56,47 +64,59 @@ class MultipleObjectAPIView(MultipleObjectMixin, GenericAPIView):
     Base class for generic views onto a queryset.
     """
 
-    pagination_serializer_class = api_settings.DEFAULT_PAGINATION_SERIALIZER_CLASS
     paginate_by = api_settings.PAGINATE_BY
+    paginate_by_param = api_settings.PAGINATE_BY_PARAM
+    pagination_serializer_class = api_settings.DEFAULT_PAGINATION_SERIALIZER_CLASS
     filter_backend = api_settings.FILTER_BACKEND
 
     def filter_queryset(self, queryset):
+        """
+        Given a queryset, filter it with whichever filter backend is in use.
+        """
         if not self.filter_backend:
             return queryset
         backend = self.filter_backend()
         return backend.filter_queryset(self.request, queryset, self)
 
-    def get_filtered_queryset(self):
-        return self.filter_queryset(self.get_queryset())
-
-    def get_pagination_serializer_class(self):
+    def get_pagination_serializer(self, page=None):
         """
-        Return the class to use for the pagination serializer.
+        Return a serializer instance to use with paginated data.
         """
         class SerializerClass(self.pagination_serializer_class):
             class Meta:
                 object_serializer_class = self.get_serializer_class()
 
-        return SerializerClass
-
-    def get_pagination_serializer(self, page=None):
-        pagination_serializer_class = self.get_pagination_serializer_class()
+        pagination_serializer_class = SerializerClass
         context = self.get_serializer_context()
         return pagination_serializer_class(instance=page, context=context)
 
+    def get_paginate_by(self, queryset):
+        """
+        Return the size of pages to use with pagination.
+        """
+        if self.paginate_by_param:
+            query_params = self.request.QUERY_PARAMS
+            try:
+                return int(query_params[self.paginate_by_param])
+            except (KeyError, ValueError):
+                pass
+        return self.paginate_by
+
 
 class SingleObjectAPIView(SingleObjectMixin, GenericAPIView):
     """
     Base class for generic views onto a model instance.
     """
+
     pk_url_kwarg = 'pk'  # Not provided in Django 1.3
     slug_url_kwarg = 'slug'  # Not provided in Django 1.3
+    slug_field = 'slug'
 
-    def get_object(self):
+    def get_object(self, queryset=None):
         """
         Override default to add support for object-level permissions.
         """
-        obj = super(SingleObjectAPIView, self).get_object()
+        obj = super(SingleObjectAPIView, self).get_object(queryset)
         if not self.has_permission(self.request, obj):
             self.permission_denied(self.request)
         return obj
@@ -153,6 +173,10 @@ class UpdateAPIView(mixins.UpdateModelMixin,
     def put(self, request, *args, **kwargs):
         return self.update(request, *args, **kwargs)
 
+    def patch(self, request, *args, **kwargs):
+        kwargs['partial'] = True
+        return self.update(request, *args, **kwargs)
+
 
 class ListCreateAPIView(mixins.ListModelMixin,
                         mixins.CreateModelMixin,
@@ -167,6 +191,23 @@ class ListCreateAPIView(mixins.ListModelMixin,
         return self.create(request, *args, **kwargs)
 
 
+class RetrieveUpdateAPIView(mixins.RetrieveModelMixin,
+                            mixins.UpdateModelMixin,
+                            SingleObjectAPIView):
+    """
+    Concrete view for retrieving, updating a model instance.
+    """
+    def get(self, request, *args, **kwargs):
+        return self.retrieve(request, *args, **kwargs)
+
+    def put(self, request, *args, **kwargs):
+        return self.update(request, *args, **kwargs)
+
+    def patch(self, request, *args, **kwargs):
+        kwargs['partial'] = True
+        return self.update(request, *args, **kwargs)
+
+
 class RetrieveDestroyAPIView(mixins.RetrieveModelMixin,
                              mixins.DestroyModelMixin,
                              SingleObjectAPIView):
@@ -193,5 +234,9 @@ class RetrieveUpdateDestroyAPIView(mixins.RetrieveModelMixin,
     def put(self, request, *args, **kwargs):
         return self.update(request, *args, **kwargs)
 
+    def patch(self, request, *args, **kwargs):
+        kwargs['partial'] = True
+        return self.update(request, *args, **kwargs)
+
     def delete(self, request, *args, **kwargs):
         return self.destroy(request, *args, **kwargs)
diff --git a/rest_framework/mixins.py b/rest_framework/mixins.py
index c3625a88..43581ae9 100644
--- a/rest_framework/mixins.py
+++ b/rest_framework/mixins.py
@@ -15,13 +15,23 @@ class CreateModelMixin(object):
     Should be mixed in with any `BaseView`.
     """
     def create(self, request, *args, **kwargs):
-        serializer = self.get_serializer(data=request.DATA)
+        serializer = self.get_serializer(data=request.DATA, files=request.FILES)
+
         if serializer.is_valid():
             self.pre_save(serializer.object)
             self.object = serializer.save()
-            return Response(serializer.data, status=status.HTTP_201_CREATED)
+            headers = self.get_success_headers(serializer.data)
+            return Response(serializer.data, status=status.HTTP_201_CREATED,
+                            headers=headers)
+
         return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
 
+    def get_success_headers(self, data):
+        try:
+            return {'Location': data['url']}
+        except (TypeError, KeyError):
+            return {}
+
     def pre_save(self, obj):
         pass
 
@@ -34,14 +44,16 @@ class ListModelMixin(object):
     empty_error = u"Empty list and '%(class_name)s.allow_empty' is False."
 
     def list(self, request, *args, **kwargs):
-        self.object_list = self.get_filtered_queryset()
+        queryset = self.get_queryset()
+        self.object_list = self.filter_queryset(queryset)
 
         # Default is to allow empty querysets.  This can be altered by setting
         # `.allow_empty = False`, to raise 404 errors on empty querysets.
         allow_empty = self.get_allow_empty()
-        if not allow_empty and len(self.object_list) == 0:
-            error_args = {'class_name': self.__class__.__name__}
-            raise Http404(self.empty_error % error_args)
+        if not allow_empty and not self.object_list:
+            class_name = self.__class__.__name__
+            error_msg = self.empty_error % {'class_name': class_name}
+            raise Http404(error_msg)
 
         # Pagination size is set by the `.paginate_by` attribute,
         # which may be `None` to disable pagination.
@@ -73,19 +85,21 @@ class UpdateModelMixin(object):
     Should be mixed in with `SingleObjectBaseView`.
     """
     def update(self, request, *args, **kwargs):
+        partial = kwargs.pop('partial', False)
         try:
             self.object = self.get_object()
-            success_status = status.HTTP_200_OK
+            success_status_code = status.HTTP_200_OK
         except Http404:
             self.object = None
-            success_status = status.HTTP_201_CREATED
+            success_status_code = status.HTTP_201_CREATED
 
-        serializer = self.get_serializer(self.object, data=request.DATA)
+        serializer = self.get_serializer(self.object, data=request.DATA,
+                                         files=request.FILES, partial=partial)
 
         if serializer.is_valid():
             self.pre_save(serializer.object)
             self.object = serializer.save()
-            return Response(serializer.data, status=success_status)
+            return Response(serializer.data, status=success_status_code)
 
         return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
 
@@ -103,6 +117,11 @@ class UpdateModelMixin(object):
             slug_field = self.get_slug_field()
             setattr(obj, slug_field, slug)
 
+        # Ensure we clean the attributes so that we don't eg return integer
+        # pk using a string representation, as provided by the url conf kwarg.
+        if hasattr(obj, 'full_clean'):
+            obj.full_clean()
+
 
 class DestroyModelMixin(object):
     """
@@ -110,6 +129,6 @@ class DestroyModelMixin(object):
     Should be mixed in with `SingleObjectBaseView`.
     """
     def destroy(self, request, *args, **kwargs):
-        self.object = self.get_object()
-        self.object.delete()
+        obj = self.get_object()
+        obj.delete()
         return Response(status=status.HTTP_204_NO_CONTENT)
diff --git a/rest_framework/negotiation.py b/rest_framework/negotiation.py
index dae38477..ee2800a6 100644
--- a/rest_framework/negotiation.py
+++ b/rest_framework/negotiation.py
@@ -2,6 +2,7 @@ from django.http import Http404
 from rest_framework import exceptions
 from rest_framework.settings import api_settings
 from rest_framework.utils.mediatypes import order_by_precedence, media_type_matches
+from rest_framework.utils.mediatypes import _MediaType
 
 
 class BaseContentNegotiation(object):
@@ -48,7 +49,8 @@ class DefaultContentNegotiation(BaseContentNegotiation):
                 for media_type in media_type_set:
                     if media_type_matches(renderer.media_type, media_type):
                         # Return the most specific media type as accepted.
-                        if len(renderer.media_type) > len(media_type):
+                        if (_MediaType(renderer.media_type).precedence >
+                            _MediaType(media_type).precedence):
                             # Eg client requests '*/*'
                             # Accepted media type is 'application/json'
                             return renderer, renderer.media_type
diff --git a/rest_framework/parsers.py b/rest_framework/parsers.py
index 4841676c..149d6431 100644
--- a/rest_framework/parsers.py
+++ b/rest_framework/parsers.py
@@ -8,11 +8,11 @@ on the request, such as form content or json encoded data.
 from django.http import QueryDict
 from django.http.multipartparser import MultiPartParser as DjangoMultiPartParser
 from django.http.multipartparser import MultiPartParserError
-from django.utils import simplejson as json
 from rest_framework.compat import yaml, ETParseError
 from rest_framework.exceptions import ParseError
 from xml.etree import ElementTree as ET
 from xml.parsers.expat import ExpatError
+import json
 import datetime
 import decimal
 
diff --git a/rest_framework/relations.py b/rest_framework/relations.py
new file mode 100644
index 00000000..0d93f448
--- /dev/null
+++ b/rest_framework/relations.py
@@ -0,0 +1,503 @@
+from django.core.exceptions import ObjectDoesNotExist, ValidationError
+from django.core.urlresolvers import resolve, get_script_prefix
+from django import forms
+from django.forms import widgets
+from django.forms.models import ModelChoiceIterator
+from django.utils.encoding import smart_unicode
+from django.utils.translation import ugettext_lazy as _
+from rest_framework.fields import Field, WritableField
+from rest_framework.reverse import reverse
+from urlparse import urlparse
+
+##### Relational fields #####
+
+
+# Not actually Writable, but subclasses may need to be.
+class RelatedField(WritableField):
+    """
+    Base class for related model fields.
+
+    If not overridden, this represents a to-one relationship, using the unicode
+    representation of the target.
+    """
+    widget = widgets.Select
+    cache_choices = False
+    empty_label = None
+    default_read_only = True  # TODO: Remove this
+
+    def __init__(self, *args, **kwargs):
+        self.queryset = kwargs.pop('queryset', None)
+        self.null = kwargs.pop('null', False)
+        super(RelatedField, self).__init__(*args, **kwargs)
+        self.read_only = kwargs.pop('read_only', self.default_read_only)
+
+    def initialize(self, parent, field_name):
+        super(RelatedField, self).initialize(parent, field_name)
+        if self.queryset is None and not self.read_only:
+            try:
+                manager = getattr(self.parent.opts.model, self.source or field_name)
+                if hasattr(manager, 'related'):  # Forward
+                    self.queryset = manager.related.model._default_manager.all()
+                else:  # Reverse
+                    self.queryset = manager.field.rel.to._default_manager.all()
+            except:
+                raise
+                msg = ('Serializer related fields must include a `queryset`' +
+                       ' argument or set `read_only=True')
+                raise Exception(msg)
+
+    ### We need this stuff to make form choices work...
+
+    # def __deepcopy__(self, memo):
+    #     result = super(RelatedField, self).__deepcopy__(memo)
+    #     result.queryset = result.queryset
+    #     return result
+
+    def prepare_value(self, obj):
+        return self.to_native(obj)
+
+    def label_from_instance(self, obj):
+        """
+        Return a readable representation for use with eg. select widgets.
+        """
+        desc = smart_unicode(obj)
+        ident = smart_unicode(self.to_native(obj))
+        if desc == ident:
+            return desc
+        return "%s - %s" % (desc, ident)
+
+    def _get_queryset(self):
+        return self._queryset
+
+    def _set_queryset(self, queryset):
+        self._queryset = queryset
+        self.widget.choices = self.choices
+
+    queryset = property(_get_queryset, _set_queryset)
+
+    def _get_choices(self):
+        # If self._choices is set, then somebody must have manually set
+        # the property self.choices. In this case, just return self._choices.
+        if hasattr(self, '_choices'):
+            return self._choices
+
+        # Otherwise, execute the QuerySet in self.queryset to determine the
+        # choices dynamically. Return a fresh ModelChoiceIterator that has not been
+        # consumed. Note that we're instantiating a new ModelChoiceIterator *each*
+        # time _get_choices() is called (and, thus, each time self.choices is
+        # accessed) so that we can ensure the QuerySet has not been consumed. This
+        # construct might look complicated but it allows for lazy evaluation of
+        # the queryset.
+        return ModelChoiceIterator(self)
+
+    def _set_choices(self, value):
+        # Setting choices also sets the choices on the widget.
+        # choices can be any iterable, but we call list() on it because
+        # it will be consumed more than once.
+        self._choices = self.widget.choices = list(value)
+
+    choices = property(_get_choices, _set_choices)
+
+    ### Regular serializer stuff...
+
+    def field_to_native(self, obj, field_name):
+        value = getattr(obj, self.source or field_name)
+        return self.to_native(value)
+
+    def field_from_native(self, data, files, field_name, into):
+        if self.read_only:
+            return
+
+        try:
+            value = data[field_name]
+        except KeyError:
+            if self.required:
+                raise ValidationError(self.error_messages['required'])
+            return
+
+        if value in (None, '') and not self.null:
+            raise ValidationError('Value may not be null')
+        elif value in (None, '') and self.null:
+            into[(self.source or field_name)] = None
+        else:
+            into[(self.source or field_name)] = self.from_native(value)
+
+
+class ManyRelatedMixin(object):
+    """
+    Mixin to convert a related field to a many related field.
+    """
+    widget = widgets.SelectMultiple
+
+    def field_to_native(self, obj, field_name):
+        value = getattr(obj, self.source or field_name)
+        return [self.to_native(item) for item in value.all()]
+
+    def field_from_native(self, data, files, field_name, into):
+        if self.read_only:
+            return
+
+        try:
+            # Form data
+            value = data.getlist(self.source or field_name)
+        except:
+            # Non-form data
+            value = data.get(self.source or field_name)
+        else:
+            if value == ['']:
+                value = []
+
+        into[field_name] = [self.from_native(item) for item in value]
+
+
+class ManyRelatedField(ManyRelatedMixin, RelatedField):
+    """
+    Base class for related model managers.
+
+    If not overridden, this represents a to-many relationship, using the unicode
+    representations of the target, and is read-only.
+    """
+    pass
+
+
+### PrimaryKey relationships
+
+class PrimaryKeyRelatedField(RelatedField):
+    """
+    Represents a to-one relationship as a pk value.
+    """
+    default_read_only = False
+    form_field_class = forms.ChoiceField
+
+    default_error_messages = {
+        'does_not_exist': _("Invalid pk '%s' - object does not exist."),
+        'invalid': _('Invalid value.'),
+    }
+
+    # TODO: Remove these field hacks...
+    def prepare_value(self, obj):
+        return self.to_native(obj.pk)
+
+    def label_from_instance(self, obj):
+        """
+        Return a readable representation for use with eg. select widgets.
+        """
+        desc = smart_unicode(obj)
+        ident = smart_unicode(self.to_native(obj.pk))
+        if desc == ident:
+            return desc
+        return "%s - %s" % (desc, ident)
+
+    # TODO: Possibly change this to just take `obj`, through prob less performant
+    def to_native(self, pk):
+        return pk
+
+    def from_native(self, data):
+        if self.queryset is None:
+            raise Exception('Writable related fields must include a `queryset` argument')
+
+        try:
+            return self.queryset.get(pk=data)
+        except ObjectDoesNotExist:
+            msg = self.error_messages['does_not_exist'] % smart_unicode(data)
+            raise ValidationError(msg)
+        except (TypeError, ValueError):
+            msg = self.error_messages['invalid']
+            raise ValidationError(msg)
+
+    def field_to_native(self, obj, field_name):
+        try:
+            # Prefer obj.serializable_value for performance reasons
+            pk = obj.serializable_value(self.source or field_name)
+        except AttributeError:
+            # RelatedObject (reverse relationship)
+            obj = getattr(obj, self.source or field_name)
+            return self.to_native(obj.pk)
+        # Forward relationship
+        return self.to_native(pk)
+
+
+class ManyPrimaryKeyRelatedField(ManyRelatedField):
+    """
+    Represents a to-many relationship as a pk value.
+    """
+    default_read_only = False
+    form_field_class = forms.MultipleChoiceField
+
+    default_error_messages = {
+        'does_not_exist': _("Invalid pk '%s' - object does not exist."),
+        'invalid': _('Invalid value.'),
+    }
+
+    def prepare_value(self, obj):
+        return self.to_native(obj.pk)
+
+    def label_from_instance(self, obj):
+        """
+        Return a readable representation for use with eg. select widgets.
+        """
+        desc = smart_unicode(obj)
+        ident = smart_unicode(self.to_native(obj.pk))
+        if desc == ident:
+            return desc
+        return "%s - %s" % (desc, ident)
+
+    def to_native(self, pk):
+        return pk
+
+    def field_to_native(self, obj, field_name):
+        try:
+            # Prefer obj.serializable_value for performance reasons
+            queryset = obj.serializable_value(self.source or field_name)
+        except AttributeError:
+            # RelatedManager (reverse relationship)
+            queryset = getattr(obj, self.source or field_name)
+            return [self.to_native(item.pk) for item in queryset.all()]
+        # Forward relationship
+        return [self.to_native(item.pk) for item in queryset.all()]
+
+    def from_native(self, data):
+        if self.queryset is None:
+            raise Exception('Writable related fields must include a `queryset` argument')
+
+        try:
+            return self.queryset.get(pk=data)
+        except ObjectDoesNotExist:
+            msg = self.error_messages['does_not_exist'] % smart_unicode(data)
+            raise ValidationError(msg)
+        except (TypeError, ValueError):
+            msg = self.error_messages['invalid']
+            raise ValidationError(msg)
+
+### Slug relationships
+
+
+class SlugRelatedField(RelatedField):
+    default_read_only = False
+    form_field_class = forms.ChoiceField
+
+    default_error_messages = {
+        'does_not_exist': _("Object with %s=%s does not exist."),
+        'invalid': _('Invalid value.'),
+    }
+
+    def __init__(self, *args, **kwargs):
+        self.slug_field = kwargs.pop('slug_field', None)
+        assert self.slug_field, 'slug_field is required'
+        super(SlugRelatedField, self).__init__(*args, **kwargs)
+
+    def to_native(self, obj):
+        return getattr(obj, self.slug_field)
+
+    def from_native(self, data):
+        if self.queryset is None:
+            raise Exception('Writable related fields must include a `queryset` argument')
+
+        try:
+            return self.queryset.get(**{self.slug_field: data})
+        except ObjectDoesNotExist:
+            raise ValidationError(self.error_messages['does_not_exist'] %
+                                  (self.slug_field, unicode(data)))
+        except (TypeError, ValueError):
+            msg = self.error_messages['invalid']
+            raise ValidationError(msg)
+
+
+class ManySlugRelatedField(ManyRelatedMixin, SlugRelatedField):
+    form_field_class = forms.MultipleChoiceField
+
+
+### Hyperlinked relationships
+
+class HyperlinkedRelatedField(RelatedField):
+    """
+    Represents a to-one relationship, using hyperlinking.
+    """
+    pk_url_kwarg = 'pk'
+    slug_field = 'slug'
+    slug_url_kwarg = None  # Defaults to same as `slug_field` unless overridden
+    default_read_only = False
+    form_field_class = forms.ChoiceField
+
+    default_error_messages = {
+        'no_match': _('Invalid hyperlink - No URL match'),
+        'incorrect_match': _('Invalid hyperlink - Incorrect URL match'),
+        'configuration_error': _('Invalid hyperlink due to configuration error'),
+        'does_not_exist': _("Invalid hyperlink - object does not exist."),
+        'invalid': _('Invalid value.'),
+    }
+
+    def __init__(self, *args, **kwargs):
+        try:
+            self.view_name = kwargs.pop('view_name')
+        except:
+            raise ValueError("Hyperlinked field requires 'view_name' kwarg")
+
+        self.slug_field = kwargs.pop('slug_field', self.slug_field)
+        default_slug_kwarg = self.slug_url_kwarg or self.slug_field
+        self.pk_url_kwarg = kwargs.pop('pk_url_kwarg', self.pk_url_kwarg)
+        self.slug_url_kwarg = kwargs.pop('slug_url_kwarg', default_slug_kwarg)
+
+        self.format = kwargs.pop('format', None)
+        super(HyperlinkedRelatedField, self).__init__(*args, **kwargs)
+
+    def get_slug_field(self):
+        """
+        Get the name of a slug field to be used to look up by slug.
+        """
+        return self.slug_field
+
+    def to_native(self, obj):
+        view_name = self.view_name
+        request = self.context.get('request', None)
+        format = self.format or self.context.get('format', None)
+        pk = getattr(obj, 'pk', None)
+        if pk is None:
+            return
+        kwargs = {self.pk_url_kwarg: pk}
+        try:
+            return reverse(view_name, kwargs=kwargs, request=request, format=format)
+        except:
+            pass
+
+        slug = getattr(obj, self.slug_field, None)
+
+        if not slug:
+            raise Exception('Could not resolve URL for field using view name "%s"' % view_name)
+
+        kwargs = {self.slug_url_kwarg: slug}
+        try:
+            return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
+        except:
+            pass
+
+        kwargs = {self.pk_url_kwarg: obj.pk, self.slug_url_kwarg: slug}
+        try:
+            return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
+        except:
+            pass
+
+        raise Exception('Could not resolve URL for field using view name "%s"' % view_name)
+
+    def from_native(self, value):
+        # Convert URL -> model instance pk
+        # TODO: Use values_list
+        if self.queryset is None:
+            raise Exception('Writable related fields must include a `queryset` argument')
+
+        try:
+            http_prefix = value.startswith('http:') or value.startswith('https:')
+        except AttributeError:
+            msg = self.error_messages['invalid']
+            raise ValidationError(msg)
+
+        if http_prefix:
+            # If needed convert absolute URLs to relative path
+            value = urlparse(value).path
+            prefix = get_script_prefix()
+            if value.startswith(prefix):
+                value = '/' + value[len(prefix):]
+
+        try:
+            match = resolve(value)
+        except:
+            raise ValidationError(self.error_messages['no_match'])
+
+        if match.view_name != self.view_name:
+            raise ValidationError(self.error_messages['incorrect_match'])
+
+        pk = match.kwargs.get(self.pk_url_kwarg, None)
+        slug = match.kwargs.get(self.slug_url_kwarg, None)
+
+        # Try explicit primary key.
+        if pk is not None:
+            queryset = self.queryset.filter(pk=pk)
+        # Next, try looking up by slug.
+        elif slug is not None:
+            slug_field = self.get_slug_field()
+            queryset = self.queryset.filter(**{slug_field: slug})
+        # If none of those are defined, it's probably a configuation error.
+        else:
+            raise ValidationError(self.error_messages['configuration_error'])
+
+        try:
+            obj = queryset.get()
+        except ObjectDoesNotExist:
+            raise ValidationError(self.error_messages['does_not_exist'])
+        except (TypeError, ValueError):
+            msg = self.error_messages['invalid']
+            raise ValidationError(msg)
+
+        return obj
+
+
+class ManyHyperlinkedRelatedField(ManyRelatedMixin, HyperlinkedRelatedField):
+    """
+    Represents a to-many relationship, using hyperlinking.
+    """
+    form_field_class = forms.MultipleChoiceField
+
+
+class HyperlinkedIdentityField(Field):
+    """
+    Represents the instance, or a property on the instance, using hyperlinking.
+    """
+    pk_url_kwarg = 'pk'
+    slug_field = 'slug'
+    slug_url_kwarg = None  # Defaults to same as `slug_field` unless overridden
+
+    def __init__(self, *args, **kwargs):
+        # TODO: Make view_name mandatory, and have the
+        # HyperlinkedModelSerializer set it on-the-fly
+        self.view_name = kwargs.pop('view_name', None)
+        # Optionally the format of the target hyperlink may be specified
+        self.format = kwargs.pop('format', None)
+
+        self.slug_field = kwargs.pop('slug_field', self.slug_field)
+        default_slug_kwarg = self.slug_url_kwarg or self.slug_field
+        self.pk_url_kwarg = kwargs.pop('pk_url_kwarg', self.pk_url_kwarg)
+        self.slug_url_kwarg = kwargs.pop('slug_url_kwarg', default_slug_kwarg)
+
+        super(HyperlinkedIdentityField, self).__init__(*args, **kwargs)
+
+    def field_to_native(self, obj, field_name):
+        request = self.context.get('request', None)
+        format = self.context.get('format', None)
+        view_name = self.view_name or self.parent.opts.view_name
+        kwargs = {self.pk_url_kwarg: obj.pk}
+
+        # By default use whatever format is given for the current context
+        # unless the target is a different type to the source.
+        #
+        # Eg. Consider a HyperlinkedIdentityField pointing from a json
+        # representation to an html property of that representation...
+        #
+        # '/snippets/1/' should link to '/snippets/1/highlight/'
+        # ...but...
+        # '/snippets/1/.json' should link to '/snippets/1/highlight/.html'
+        if format and self.format and self.format != format:
+            format = self.format
+
+        try:
+            return reverse(view_name, kwargs=kwargs, request=request, format=format)
+        except:
+            pass
+
+        slug = getattr(obj, self.slug_field, None)
+
+        if not slug:
+            raise Exception('Could not resolve URL for field using view name "%s"' % view_name)
+
+        kwargs = {self.slug_url_kwarg: slug}
+        try:
+            return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
+        except:
+            pass
+
+        kwargs = {self.pk_url_kwarg: obj.pk, self.slug_url_kwarg: slug}
+        try:
+            return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
+        except:
+            pass
+
+        raise Exception('Could not resolve URL for field using view name "%s"' % view_name)
diff --git a/rest_framework/renderers.py b/rest_framework/renderers.py
index 22fd6e74..0a34abaa 100644
--- a/rest_framework/renderers.py
+++ b/rest_framework/renderers.py
@@ -4,14 +4,14 @@ Renderers are used to serialize a response into specific media types.
 They give us a generic way of being able to handle various media types
 on the response, such as JSON encoded data or HTML output.
 
-REST framework also provides an HTML renderer the renders the browseable API.
+REST framework also provides an HTML renderer the renders the browsable API.
 """
 import copy
 import string
+import json
 from django import forms
 from django.http.multipartparser import parse_header
 from django.template import RequestContext, loader, Template
-from django.utils import simplejson as json
 from rest_framework.compat import yaml
 from rest_framework.exceptions import ConfigurationError
 from rest_framework.settings import api_settings
@@ -19,8 +19,8 @@ from rest_framework.request import clone_request
 from rest_framework.utils import dict2xml
 from rest_framework.utils import encoders
 from rest_framework.utils.breadcrumbs import get_breadcrumbs
-from rest_framework import VERSION
-from rest_framework import serializers, parsers
+from rest_framework import VERSION, status
+from rest_framework import parsers
 
 
 class BaseRenderer(object):
@@ -306,25 +306,8 @@ class BrowsableAPIRenderer(BaseRenderer):
         return True
 
     def serializer_to_form_fields(self, serializer):
-        field_mapping = {
-            serializers.FloatField: forms.FloatField,
-            serializers.IntegerField: forms.IntegerField,
-            serializers.DateTimeField: forms.DateTimeField,
-            serializers.DateField: forms.DateField,
-            serializers.EmailField: forms.EmailField,
-            serializers.CharField: forms.CharField,
-            serializers.ChoiceField: forms.ChoiceField,
-            serializers.BooleanField: forms.BooleanField,
-            serializers.PrimaryKeyRelatedField: forms.ChoiceField,
-            serializers.ManyPrimaryKeyRelatedField: forms.MultipleChoiceField,
-            serializers.SlugRelatedField: forms.ChoiceField,
-            serializers.ManySlugRelatedField: forms.MultipleChoiceField,
-            serializers.HyperlinkedRelatedField: forms.ChoiceField,
-            serializers.ManyHyperlinkedRelatedField: forms.MultipleChoiceField
-        }
-
         fields = {}
-        for k, v in serializer.get_fields(True).items():
+        for k, v in serializer.get_fields().items():
             if getattr(v, 'read_only', True):
                 continue
 
@@ -337,6 +320,9 @@ class BrowsableAPIRenderer(BaseRenderer):
             if getattr(v, 'choices', None) is not None:
                 kwargs['choices'] = v.choices
 
+            if getattr(v, 'regex', None) is not None:
+                kwargs['regex'] = v.regex
+
             if getattr(v, 'widget', None):
                 widget = copy.deepcopy(v.widget)
                 kwargs['widget'] = widget
@@ -346,13 +332,7 @@ class BrowsableAPIRenderer(BaseRenderer):
 
             kwargs['label'] = k
 
-            try:
-                fields[k] = field_mapping[v.__class__](**kwargs)
-            except KeyError:
-                if getattr(v, 'choices', None) is not None:
-                    fields[k] = forms.ChoiceField(**kwargs)
-                else:
-                    fields[k] = forms.CharField(**kwargs)
+            fields[k] = v.form_field_class(**kwargs)
         return fields
 
     def get_form(self, view, method, request):
@@ -479,7 +459,7 @@ class BrowsableAPIRenderer(BaseRenderer):
         # Munge DELETE Response code to allow us to return content
         # (Do this *after* we've rendered the template so that we include
         # the normal deletion response code in the output)
-        if response.status_code == 204:
-            response.status_code = 200
+        if response.status_code == status.HTTP_204_NO_CONTENT:
+            response.status_code = status.HTTP_200_OK
 
         return ret
diff --git a/rest_framework/request.py b/rest_framework/request.py
index 38ee36dd..1c28cd17 100644
--- a/rest_framework/request.py
+++ b/rest_framework/request.py
@@ -170,6 +170,15 @@ class Request(object):
             self._authenticator, self._user, self._auth = self._authenticate()
         return self._user
 
+    @user.setter
+    def user(self, value):
+         """
+         Sets the user on the current request. This is necessary to maintain
+         compatilbility with django.contrib.auth where the user proprety is
+         set in the login and logout functions.
+         """
+         self._user = value
+
     @property
     def auth(self):
         """
@@ -180,6 +189,14 @@ class Request(object):
             self._authenticator, self._user, self._auth = self._authenticate()
         return self._auth
 
+    @auth.setter
+    def auth(self, value):
+        """
+        Sets any non-user authentication information associated with the
+        request, such as an authentication token.
+        """
+        self._auth = value
+
     @property
     def successful_authenticator(self):
         """
diff --git a/rest_framework/response.py b/rest_framework/response.py
index 0de01204..be78c43a 100644
--- a/rest_framework/response.py
+++ b/rest_framework/response.py
@@ -15,14 +15,17 @@ class Response(SimpleTemplateResponse):
         Alters the init arguments slightly.
         For example, drop 'template_name', and instead use 'data'.
 
-        Setting 'renderer' and 'media_type' will typically be defered,
+        Setting 'renderer' and 'media_type' will typically be deferred,
         For example being set automatically by the `APIView`.
         """
         super(Response, self).__init__(None, status=status)
         self.data = data
-        self.headers = headers and headers[:] or []
         self.template_name = template_name
         self.exception = exception
+        
+        if headers:
+            for name,value in headers.iteritems():
+                self[name] = value
 
     @property
     def rendered_content(self):
diff --git a/rest_framework/runtests/runcoverage.py b/rest_framework/runtests/runcoverage.py
index 0ce379eb..bcab1d14 100755
--- a/rest_framework/runtests/runcoverage.py
+++ b/rest_framework/runtests/runcoverage.py
@@ -8,6 +8,9 @@ Useful tool to run the test suite for rest_framework and generate a coverage rep
 # http://code.djangoproject.com/svn/django/trunk/tests/runtests.py
 import os
 import sys
+
+# fix sys path so we don't need to setup PYTHONPATH
+sys.path.append(os.path.join(os.path.dirname(__file__), "../.."))
 os.environ['DJANGO_SETTINGS_MODULE'] = 'rest_framework.runtests.settings'
 
 from coverage import coverage
@@ -55,6 +58,12 @@ def main():
         if 'compat.py' in files:
             files.remove('compat.py')
 
+        # Same applies to template tags module.
+        # This module has to include branching on Django versions,
+        # so it's never possible for it to have full coverage.
+        if 'rest_framework.py' in files:
+            files.remove('rest_framework.py')
+
         cov_files.extend([os.path.join(path, file) for file in files if file.endswith('.py')])
 
     cov.report(cov_files)
diff --git a/rest_framework/runtests/runtests.py b/rest_framework/runtests/runtests.py
index 1bd0a5fc..505994e2 100755
--- a/rest_framework/runtests/runtests.py
+++ b/rest_framework/runtests/runtests.py
@@ -5,6 +5,9 @@
 # http://code.djangoproject.com/svn/django/trunk/tests/runtests.py
 import os
 import sys
+
+# fix sys path so we don't need to setup PYTHONPATH
+sys.path.append(os.path.join(os.path.dirname(__file__), "../.."))
 os.environ['DJANGO_SETTINGS_MODULE'] = 'rest_framework.runtests.settings'
 
 from django.conf import settings
diff --git a/rest_framework/runtests/urls.py b/rest_framework/runtests/urls.py
index 4b7da787..ed5baeae 100644
--- a/rest_framework/runtests/urls.py
+++ b/rest_framework/runtests/urls.py
@@ -1,7 +1,7 @@
 """
 Blank URLConf just to keep runtests.py happy.
 """
-from django.conf.urls.defaults import *
+from rest_framework.compat import patterns
 
 urlpatterns = patterns('',
 )
diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index 95145d58..fa92838b 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -14,7 +14,7 @@ from rest_framework.compat import get_concrete_model
 # This helps keep the seperation between model fields, form fields, and
 # serializer fields more explicit.
 
-
+from rest_framework.relations import *
 from rest_framework.fields import *
 
 
@@ -22,7 +22,16 @@ class DictWithMetadata(dict):
     """
     A dict-like object, that can have additional properties attached.
     """
-    pass
+    def __getstate__(self):
+        """
+        Used by pickle (e.g., caching).
+        Overriden to remove metadata from the dict, since it shouldn't be pickled
+        and may in some instances be unpickleable.
+        """
+        # return an instance of the first dict in MRO that isn't a DictWithMetadata
+        for base in self.__class__.__mro__:
+            if not isinstance(base, DictWithMetadata) and isinstance(base, dict):
+                return base(self)
 
 
 class SortedDictWithMetadata(SortedDict, DictWithMetadata):
@@ -60,7 +69,7 @@ def _get_declared_fields(bases, attrs):
 
     # If this class is subclassing another Serializer, add that Serializer's
     # fields.  Note that we loop over the bases in *reverse*. This is necessary
-    # in order to the correct order of fields.
+    # in order to maintain the correct order of fields.
     for base in bases[::-1]:
         if hasattr(base, 'base_fields'):
             fields = base.base_fields.items() + fields
@@ -89,50 +98,53 @@ class BaseSerializer(Field):
         pass
 
     _options_class = SerializerOptions
-    _dict_class = SortedDictWithMetadata  # Set to unsorted dict for backwards compatability with unsorted implementations.
+    _dict_class = SortedDictWithMetadata  # Set to unsorted dict for backwards compatibility with unsorted implementations.
 
-    def __init__(self, instance=None, data=None, context=None, **kwargs):
+    def __init__(self, instance=None, data=None, files=None,
+                 context=None, partial=False, **kwargs):
         super(BaseSerializer, self).__init__(**kwargs)
         self.opts = self._options_class(self.Meta)
-        self.fields = copy.deepcopy(self.base_fields)
         self.parent = None
         self.root = None
+        self.partial = partial
 
         self.context = context or {}
 
         self.init_data = data
+        self.init_files = files
         self.object = instance
+        self.fields = self.get_fields()
 
         self._data = None
+        self._files = None
         self._errors = None
 
     #####
     # Methods to determine which fields to use when (de)serializing objects.
 
-    def default_fields(self, nested=False):
+    def get_default_fields(self):
         """
         Return the complete set of default fields for the object, as a dict.
         """
         return {}
 
-    def get_fields(self, nested=False):
+    def get_fields(self):
         """
         Returns the complete set of fields for the object as a dict.
 
         This will be the set of any explicitly declared fields,
-        plus the set of fields returned by default_fields().
+        plus the set of fields returned by get_default_fields().
         """
         ret = SortedDict()
 
         # Get the explicitly declared fields
-        for key, field in self.fields.items():
+        base_fields = copy.deepcopy(self.base_fields)
+        for key, field in base_fields.items():
             ret[key] = field
-            # Set up the field
-            field.initialize(parent=self, field_name=key)
 
         # Add in the default fields
-        fields = self.default_fields(nested)
-        for key, val in fields.items():
+        default_fields = self.get_default_fields()
+        for key, val in default_fields.items():
             if key not in ret:
                 ret[key] = val
 
@@ -148,6 +160,9 @@ class BaseSerializer(Field):
             for key in self.opts.exclude:
                 ret.pop(key, None)
 
+        for key, field in ret.items():
+            field.initialize(parent=self, field_name=key)
+
         return ret
 
     #####
@@ -163,7 +178,7 @@ class BaseSerializer(Field):
             self.opts.depth = parent.opts.depth - 1
 
     #####
-    # Methods to convert or revert from objects <--> primative representations.
+    # Methods to convert or revert from objects <--> primitive representations.
 
     def get_field_key(self, field_name):
         """
@@ -179,24 +194,29 @@ class BaseSerializer(Field):
         ret = self._dict_class()
         ret.fields = {}
 
-        fields = self.get_fields(nested=bool(self.opts.depth))
-        for field_name, field in fields.items():
+        for field_name, field in self.fields.items():
+            field.initialize(parent=self, field_name=field_name)
             key = self.get_field_key(field_name)
             value = field.field_to_native(obj, field_name)
             ret[key] = value
             ret.fields[key] = field
         return ret
 
-    def restore_fields(self, data):
+    def restore_fields(self, data, files):
         """
         Core of deserialization, together with `restore_object`.
         Converts a dictionary of data into a dictionary of deserialized fields.
         """
-        fields = self.get_fields(nested=bool(self.opts.depth))
         reverted_data = {}
-        for field_name, field in fields.items():
+
+        if data is not None and not isinstance(data, dict):
+            self._errors['non_field_errors'] = [u'Invalid data']
+            return None
+
+        for field_name, field in self.fields.items():
+            field.initialize(parent=self, field_name=field_name)
             try:
-                field.field_from_native(data, field_name, reverted_data)
+                field.field_from_native(data, files, field_name, reverted_data)
             except ValidationError as err:
                 self._errors[field_name] = list(err.messages)
 
@@ -206,10 +226,7 @@ class BaseSerializer(Field):
         """
         Run `validate_<fieldname>()` and `validate()` methods on the serializer
         """
-        # TODO: refactor this so we're not determining the fields again
-        fields = self.get_fields(nested=bool(self.opts.depth))
-
-        for field_name, field in fields.items():
+        for field_name, field in self.fields.items():
             try:
                 validate_method = getattr(self, 'validate_%s' % field_name, None)
                 if validate_method:
@@ -218,10 +235,18 @@ class BaseSerializer(Field):
             except ValidationError as err:
                 self._errors[field_name] = self._errors.get(field_name, []) + list(err.messages)
 
-        try:
-            attrs = self.validate(attrs)
-        except ValidationError as err:
-            self._errors['non_field_errors'] = err.messages
+        # If there are already errors, we don't run .validate() because
+        # field-validation failed and thus `attrs` may not be complete.
+        # which in turn can cause inconsistent validation errors.
+        if not self._errors:
+            try:
+                attrs = self.validate(attrs)
+            except ValidationError as err:
+                if hasattr(err, 'message_dict'):
+                    for field_name, error_messages in err.message_dict.items():
+                        self._errors[field_name] = self._errors.get(field_name, []) + list(error_messages)
+                elif hasattr(err, 'messages'):
+                    self._errors['non_field_errors'] = err.messages
 
         return attrs
 
@@ -244,23 +269,23 @@ class BaseSerializer(Field):
 
     def to_native(self, obj):
         """
-        Serialize objects -> primatives.
+        Serialize objects -> primitives.
         """
         if hasattr(obj, '__iter__'):
             return [self.convert_object(item) for item in obj]
         return self.convert_object(obj)
 
-    def from_native(self, data):
+    def from_native(self, data, files):
         """
-        Deserialize primatives -> objects.
+        Deserialize primitives -> objects.
         """
         if hasattr(data, '__iter__') and not isinstance(data, dict):
             # TODO: error data when deserializing lists
-            return (self.from_native(item) for item in data)
+            return [self.from_native(item, None) for item in data]
 
         self._errors = {}
-        if data is not None:
-            attrs = self.restore_fields(data)
+        if data is not None or files is not None:
+            attrs = self.restore_fields(data, files)
             attrs = self.perform_validation(attrs)
         else:
             self._errors['non_field_errors'] = ['No input provided']
@@ -273,12 +298,23 @@ class BaseSerializer(Field):
         Override default so that we can apply ModelSerializer as a nested
         field to relationships.
         """
-        obj = getattr(obj, self.source or field_name)
+        if self.source:
+            for component in self.source.split('.'):
+                obj = getattr(obj, component)
+                if is_simple_callable(obj):
+                    obj = obj()
+        else:
+            obj = getattr(obj, field_name)
+            if is_simple_callable(obj):
+                obj = value()
 
         # If the object has an "all" method, assume it's a relationship
         if is_simple_callable(getattr(obj, 'all', None)):
             return [self.to_native(item) for item in obj.all()]
 
+        if obj is None:
+            return None
+
         return self.to_native(obj)
 
     @property
@@ -288,7 +324,7 @@ class BaseSerializer(Field):
         setting self.object if no errors occurred.
         """
         if self._errors is None:
-            obj = self.from_native(self.init_data)
+            obj = self.from_native(self.init_data, self.init_files)
             if not self._errors:
                 self.object = obj
         return self._errors
@@ -321,6 +357,7 @@ class ModelSerializerOptions(SerializerOptions):
     def __init__(self, meta):
         super(ModelSerializerOptions, self).__init__(meta)
         self.model = getattr(meta, 'model', None)
+        self.read_only_fields = getattr(meta, 'read_only_fields', ())
 
 
 class ModelSerializer(Serializer):
@@ -329,16 +366,10 @@ class ModelSerializer(Serializer):
     """
     _options_class = ModelSerializerOptions
 
-    def default_fields(self, nested=False):
+    def get_default_fields(self):
         """
         Return all the fields that should be serialized for the model.
         """
-        # TODO: Modfiy this so that it's called on init, and drop
-        #       serialize/obj/data arguments.
-        #
-        #       We *could* provide a hook for dynamic fields, but
-        #       it'd be nice if the default was to generate fields statically
-        #       at the point of __init__
 
         cls = self.opts.model
         opts = get_concrete_model(cls)._meta
@@ -350,6 +381,7 @@ class ModelSerializer(Serializer):
         fields += [field for field in opts.many_to_many if field.serialize]
 
         ret = SortedDict()
+        nested = bool(self.opts.depth)
         is_pk = True  # First field in the list is the pk
 
         for model_field in fields:
@@ -366,9 +398,14 @@ class ModelSerializer(Serializer):
                 field = self.get_field(model_field)
 
             if field:
-                field.initialize(parent=self, field_name=model_field.name)
                 ret[model_field.name] = field
 
+        for field_name in self.opts.read_only_fields:
+            assert field_name in ret, \
+                "read_only_fields on '%s' included invalid item '%s'" % \
+                (self.__class__.__name__, field_name)
+            ret[field_name].read_only = True
+
         return ret
 
     def get_pk_field(self, model_field):
@@ -381,7 +418,10 @@ class ModelSerializer(Serializer):
         """
         Creates a default instance of a nested relational field.
         """
-        return ModelSerializer()
+        class NestedModelSerializer(ModelSerializer):
+            class Meta:
+                model = model_field.rel.to
+        return NestedModelSerializer()
 
     def get_related_field(self, model_field, to_many=False):
         """
@@ -389,10 +429,14 @@ class ModelSerializer(Serializer):
         """
         # TODO: filter queryset using:
         # .using(db).complex_filter(self.rel.limit_choices_to)
-        queryset = model_field.rel.to._default_manager
+        kwargs = {
+            'null': model_field.null,
+            'queryset': model_field.rel.to._default_manager
+        }
+
         if to_many:
-            return ManyPrimaryKeyRelatedField(queryset=queryset)
-        return PrimaryKeyRelatedField(queryset=queryset)
+            return ManyPrimaryKeyRelatedField(**kwargs)
+        return PrimaryKeyRelatedField(**kwargs)
 
     def get_field(self, model_field):
         """
@@ -402,7 +446,7 @@ class ModelSerializer(Serializer):
 
         kwargs['blank'] = model_field.blank
 
-        if model_field.null:
+        if model_field.null or model_field.blank:
             kwargs['required'] = False
 
         if model_field.has_default():
@@ -427,49 +471,86 @@ class ModelSerializer(Serializer):
             models.DateField: DateField,
             models.EmailField: EmailField,
             models.CharField: CharField,
+            models.URLField: URLField,
+            models.SlugField: SlugField,
             models.TextField: CharField,
             models.CommaSeparatedIntegerField: CharField,
             models.BooleanField: BooleanField,
+            models.FileField: FileField,
+            models.ImageField: ImageField,
         }
         try:
             return field_mapping[model_field.__class__](**kwargs)
         except KeyError:
             return ModelField(model_field=model_field, **kwargs)
 
+    def get_validation_exclusions(self):
+        """
+        Return a list of field names to exclude from model validation.
+        """
+        cls = self.opts.model
+        opts = get_concrete_model(cls)._meta
+        exclusions = [field.name for field in opts.fields + opts.many_to_many]
+        for field_name, field in self.fields.items():
+            if field_name in exclusions and not field.read_only:
+                exclusions.remove(field_name)
+        return exclusions
+
     def restore_object(self, attrs, instance=None):
         """
         Restore the model instance.
         """
         self.m2m_data = {}
+        self.related_data = {}
 
-        if instance:
-            for key, val in attrs.items():
-                setattr(instance, key, val)
-            return instance
+        # Reverse fk relations
+        for (obj, model) in self.opts.model._meta.get_all_related_objects_with_model():
+            field_name = obj.field.related_query_name()
+            if field_name in attrs:
+                self.related_data[field_name] = attrs.pop(field_name)
 
-        # Reverse relations
+        # Reverse m2m relations
         for (obj, model) in self.opts.model._meta.get_all_related_m2m_objects_with_model():
             field_name = obj.field.related_query_name()
             if field_name in attrs:
                 self.m2m_data[field_name] = attrs.pop(field_name)
 
-        # Forward relations
+        # Forward m2m relations
         for field in self.opts.model._meta.many_to_many:
             if field.name in attrs:
                 self.m2m_data[field.name] = attrs.pop(field.name)
-        return self.opts.model(**attrs)
 
-    def save(self, save_m2m=True):
+        if instance is not None:
+            for key, val in attrs.items():
+                setattr(instance, key, val)
+
+        else:
+            instance = self.opts.model(**attrs)
+
+        try:
+            instance.full_clean(exclude=self.get_validation_exclusions())
+        except ValidationError, err:
+            self._errors = err.message_dict
+            return None
+
+        return instance
+
+    def save(self):
         """
         Save the deserialized object and return it.
         """
         self.object.save()
 
-        if getattr(self, 'm2m_data', None) and save_m2m:
+        if getattr(self, 'm2m_data', None):
             for accessor_name, object_list in self.m2m_data.items():
                 setattr(self.object, accessor_name, object_list)
             self.m2m_data = {}
 
+        if getattr(self, 'related_data', None):
+            for accessor_name, object_list in self.related_data.items():
+                setattr(self.object, accessor_name, object_list)
+            self.related_data = {}
+
         return self.object
 
 
@@ -516,9 +597,9 @@ class HyperlinkedModelSerializer(ModelSerializer):
         # TODO: filter queryset using:
         # .using(db).complex_filter(self.rel.limit_choices_to)
         rel = model_field.rel.to
-        queryset = rel._default_manager
         kwargs = {
-            'queryset': queryset,
+            'null': model_field.null,
+            'queryset': rel._default_manager,
             'view_name': self._get_default_view_name(rel)
         }
         if to_many:
diff --git a/rest_framework/settings.py b/rest_framework/settings.py
index 906a7cf6..5c77c55c 100644
--- a/rest_framework/settings.py
+++ b/rest_framework/settings.py
@@ -54,19 +54,26 @@ DEFAULTS = {
         'user': None,
         'anon': None,
     },
+
+    # Pagination
     'PAGINATE_BY': None,
+    'PAGINATE_BY_PARAM': None,
+
+    # Filtering
     'FILTER_BACKEND': None,
 
+    # Authentication
     'UNAUTHENTICATED_USER': 'django.contrib.auth.models.AnonymousUser',
     'UNAUTHENTICATED_TOKEN': None,
 
+    # Browser enhancements
     'FORM_METHOD_OVERRIDE': '_method',
     'FORM_CONTENT_OVERRIDE': '_content',
     'FORM_CONTENTTYPE_OVERRIDE': '_content_type',
     'URL_ACCEPT_OVERRIDE': 'accept',
     'URL_FORMAT_OVERRIDE': 'format',
 
-    'FORMAT_SUFFIX_KWARG': 'format'
+    'FORMAT_SUFFIX_KWARG': 'format',
 }
 
 
@@ -108,8 +115,8 @@ def import_from_string(val, setting_name):
         module_path, class_name = '.'.join(parts[:-1]), parts[-1]
         module = importlib.import_module(module_path)
         return getattr(module, class_name)
-    except:
-        msg = "Could not import '%s' for API setting '%s'" % (val, setting_name)
+    except ImportError as e:
+        msg = "Could not import '%s' for API setting '%s'. %s: %s." % (val, setting_name, e.__class__.__name__, e)
         raise ImportError(msg)
 
 
@@ -152,7 +159,7 @@ class APISettings(object):
 
     def validate_setting(self, attr, val):
         if attr == 'FILTER_BACKEND' and val is not None:
-            # Make sure we can initilize the class
+            # Make sure we can initialize the class
             val()
 
 api_settings = APISettings(USER_SETTINGS, DEFAULTS, IMPORT_STRINGS)
diff --git a/rest_framework/templates/rest_framework/base.html b/rest_framework/templates/rest_framework/base.html
index fb0e19f0..42e49cb9 100644
--- a/rest_framework/templates/rest_framework/base.html
+++ b/rest_framework/templates/rest_framework/base.html
@@ -1,6 +1,5 @@
 {% load url from future %}
 {% load rest_framework %}
-{% load static %}
 <!DOCTYPE html>
 <html>
     <head>
@@ -14,10 +13,10 @@
         <title>{% block title %}Django REST framework{% endblock %}</title>
 
         {% block style %}
-        <link rel="stylesheet" type="text/css" href="{% get_static_prefix %}rest_framework/css/bootstrap.min.css"/>
-        <link rel="stylesheet" type="text/css" href="{% get_static_prefix %}rest_framework/css/bootstrap-tweaks.css"/>
-        <link rel="stylesheet" type="text/css" href='{% get_static_prefix %}rest_framework/css/prettify.css'/>
-        <link rel="stylesheet" type="text/css" href='{% get_static_prefix %}rest_framework/css/default.css'/>
+        <link rel="stylesheet" type="text/css" href="{% static "rest_framework/css/bootstrap.min.css" %}"/>
+        <link rel="stylesheet" type="text/css" href="{% static "rest_framework/css/bootstrap-tweaks.css" %}"/>
+        <link rel="stylesheet" type="text/css" href="{% static "rest_framework/css/prettify.css" %}"/>
+        <link rel="stylesheet" type="text/css" href="{% static "rest_framework/css/default.css" %}"/>
         {% endblock %}
 
     {% endblock %}
@@ -195,10 +194,10 @@
     {% endblock %}
 
     {% block script %}
-    <script src="{% get_static_prefix %}rest_framework/js/jquery-1.8.1-min.js"></script>
-    <script src="{% get_static_prefix %}rest_framework/js/bootstrap.min.js"></script>
-    <script src="{% get_static_prefix %}rest_framework/js/prettify-min.js"></script>
-    <script src="{% get_static_prefix %}rest_framework/js/default.js"></script>
+    <script src="{% static "rest_framework/js/jquery-1.8.1-min.js" %}"></script>
+    <script src="{% static "rest_framework/js/bootstrap.min.js" %}"></script>
+    <script src="{% static "rest_framework/js/prettify-min.js" %}"></script>
+    <script src="{% static "rest_framework/js/default.js" %}"></script>
     {% endblock %}
   </body>
 </html>
diff --git a/rest_framework/templates/rest_framework/login.html b/rest_framework/templates/rest_framework/login.html
index c1271399..6e2bd8d4 100644
--- a/rest_framework/templates/rest_framework/login.html
+++ b/rest_framework/templates/rest_framework/login.html
@@ -1,11 +1,11 @@
 {% load url from future %}
-{% load static %}
+{% load rest_framework %}
 <html>
 
     <head>
-        <link rel="stylesheet" type="text/css" href="{% get_static_prefix %}rest_framework/css/bootstrap.min.css"/>
-        <link rel="stylesheet" type="text/css" href="{% get_static_prefix %}rest_framework/css/bootstrap-tweaks.css"/>
-        <link rel="stylesheet" type="text/css" href='{% get_static_prefix %}rest_framework/css/default.css'/>
+        <link rel="stylesheet" type="text/css" href="{% static "rest_framework/css/bootstrap.min.css" %}"/>
+        <link rel="stylesheet" type="text/css" href="{% static "rest_framework/css/bootstrap-tweaks.css" %}"/>
+        <link rel="stylesheet" type="text/css" href="{% static "rest_framework/css/default.css" %}"/>
     </head>
 
     <body class="container">
diff --git a/rest_framework/templatetags/rest_framework.py b/rest_framework/templatetags/rest_framework.py
index 4e0181ee..82fcdfe7 100644
--- a/rest_framework/templatetags/rest_framework.py
+++ b/rest_framework/templatetags/rest_framework.py
@@ -11,6 +11,89 @@ import string
 register = template.Library()
 
 
+# Note we don't use 'load staticfiles', because we need a 1.3 compatible
+# version, so instead we include the `static` template tag ourselves.
+
+# When 1.3 becomes unsupported by REST framework, we can instead start to
+# use the {% load staticfiles %} tag, remove the following code,
+# and add a dependancy that `django.contrib.staticfiles` must be installed.
+
+# Note: We can't put this into the `compat` module because the compat import
+# from rest_framework.compat import ...
+# conflicts with this rest_framework template tag module.
+
+try:  # Django 1.5+
+    from django.contrib.staticfiles.templatetags.staticfiles import StaticFilesNode
+
+    @register.tag('static')
+    def do_static(parser, token):
+        return StaticFilesNode.handle_token(parser, token)
+
+except:
+    try:  # Django 1.4
+        from django.contrib.staticfiles.storage import staticfiles_storage
+
+        @register.simple_tag
+        def static(path):
+            """
+            A template tag that returns the URL to a file
+            using staticfiles' storage backend
+            """
+            return staticfiles_storage.url(path)
+
+    except:  # Django 1.3
+        from urlparse import urljoin
+        from django import template
+        from django.templatetags.static import PrefixNode
+
+        class StaticNode(template.Node):
+            def __init__(self, varname=None, path=None):
+                if path is None:
+                    raise template.TemplateSyntaxError(
+                        "Static template nodes must be given a path to return.")
+                self.path = path
+                self.varname = varname
+
+            def url(self, context):
+                path = self.path.resolve(context)
+                return self.handle_simple(path)
+
+            def render(self, context):
+                url = self.url(context)
+                if self.varname is None:
+                    return url
+                context[self.varname] = url
+                return ''
+
+            @classmethod
+            def handle_simple(cls, path):
+                return urljoin(PrefixNode.handle_simple("STATIC_URL"), path)
+
+            @classmethod
+            def handle_token(cls, parser, token):
+                """
+                Class method to parse prefix node and return a Node.
+                """
+                bits = token.split_contents()
+
+                if len(bits) < 2:
+                    raise template.TemplateSyntaxError(
+                        "'%s' takes at least one argument (path to file)" % bits[0])
+
+                path = parser.compile_filter(bits[1])
+
+                if len(bits) >= 2 and bits[-2] == 'as':
+                    varname = bits[3]
+                else:
+                    varname = None
+
+                return cls(varname, path)
+
+        @register.tag('static')
+        def do_static_13(parser, token):
+            return StaticNode.handle_token(parser, token)
+
+
 def replace_query_param(url, key, val):
     """
     Given a URL and a key/val pair, set or replace an item in the query
diff --git a/rest_framework/tests/authentication.py b/rest_framework/tests/authentication.py
index 8ab4c4e4..e86041bc 100644
--- a/rest_framework/tests/authentication.py
+++ b/rest_framework/tests/authentication.py
@@ -1,16 +1,14 @@
-from django.conf.urls.defaults import patterns
 from django.contrib.auth.models import User
-from django.test import Client, TestCase
-
-from django.utils import simplejson as json
 from django.http import HttpResponse
+from django.test import Client, TestCase
 
-from rest_framework.views import APIView
 from rest_framework import permissions
-
 from rest_framework.authtoken.models import Token
 from rest_framework.authentication import TokenAuthentication
+from rest_framework.compat import patterns
+from rest_framework.views import APIView
 
+import json
 import base64
 
 
@@ -27,6 +25,7 @@ MockView.authentication_classes += (TokenAuthentication,)
 
 urlpatterns = patterns('',
     (r'^$', MockView.as_view()),
+    (r'^auth-token/$', 'rest_framework.authtoken.views.obtain_auth_token'),
 )
 
 
@@ -152,3 +151,33 @@ class TokenAuthTests(TestCase):
         self.token.delete()
         token = Token.objects.create(user=self.user)
         self.assertTrue(bool(token.key))
+
+    def test_token_login_json(self):
+        """Ensure token login view using JSON POST works."""
+        client = Client(enforce_csrf_checks=True)
+        response = client.post('/auth-token/',
+                               json.dumps({'username': self.username, 'password': self.password}), 'application/json')
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(json.loads(response.content)['token'], self.key)
+
+    def test_token_login_json_bad_creds(self):
+        """Ensure token login view using JSON POST fails if bad credentials are used."""
+        client = Client(enforce_csrf_checks=True)
+        response = client.post('/auth-token/',
+                               json.dumps({'username': self.username, 'password': "badpass"}), 'application/json')
+        self.assertEqual(response.status_code, 400)
+
+    def test_token_login_json_missing_fields(self):
+        """Ensure token login view using JSON POST fails if missing fields."""
+        client = Client(enforce_csrf_checks=True)
+        response = client.post('/auth-token/',
+                               json.dumps({'username': self.username}), 'application/json')
+        self.assertEqual(response.status_code, 400)
+
+    def test_token_login_form(self):
+        """Ensure token login view using form POST works."""
+        client = Client(enforce_csrf_checks=True)
+        response = client.post('/auth-token/',
+                               {'username': self.username, 'password': self.password})
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(json.loads(response.content)['token'], self.key)
diff --git a/rest_framework/tests/breadcrumbs.py b/rest_framework/tests/breadcrumbs.py
index 647ab96d..df891683 100644
--- a/rest_framework/tests/breadcrumbs.py
+++ b/rest_framework/tests/breadcrumbs.py
@@ -1,5 +1,5 @@
-from django.conf.urls.defaults import patterns, url
 from django.test import TestCase
+from rest_framework.compat import patterns, url
 from rest_framework.utils.breadcrumbs import get_breadcrumbs
 from rest_framework.views import APIView
 
diff --git a/rest_framework/tests/decorators.py b/rest_framework/tests/decorators.py
index 41864d71..bc44a45b 100644
--- a/rest_framework/tests/decorators.py
+++ b/rest_framework/tests/decorators.py
@@ -1,7 +1,7 @@
 from django.test import TestCase
+from django.test.client import RequestFactory
 from rest_framework import status
 from rest_framework.response import Response
-from django.test.client import RequestFactory
 from rest_framework.renderers import JSONRenderer
 from rest_framework.parsers import JSONParser
 from rest_framework.authentication import BasicAuthentication
@@ -17,6 +17,8 @@ from rest_framework.decorators import (
     permission_classes,
 )
 
+from rest_framework.tests.utils import RequestFactory
+
 
 class DecoratorTestCase(TestCase):
 
@@ -63,6 +65,20 @@ class DecoratorTestCase(TestCase):
         response = view(request)
         self.assertEqual(response.status_code, 405)
 
+    def test_calling_patch_method(self):
+
+        @api_view(['GET', 'PATCH'])
+        def view(request):
+            return Response({})
+
+        request = self.factory.patch('/')
+        response = view(request)
+        self.assertEqual(response.status_code, 200)
+
+        request = self.factory.post('/')
+        response = view(request)
+        self.assertEqual(response.status_code, 405)
+
     def test_renderer_classes(self):
 
         @api_view(['GET'])
diff --git a/rest_framework/tests/extras/__init__.py b/rest_framework/tests/extras/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/rest_framework/tests/extras/__init__.py
diff --git a/rest_framework/tests/extras/bad_import.py b/rest_framework/tests/extras/bad_import.py
new file mode 100644
index 00000000..68263d94
--- /dev/null
+++ b/rest_framework/tests/extras/bad_import.py
@@ -0,0 +1 @@
+raise ValueError
diff --git a/rest_framework/tests/files.py b/rest_framework/tests/files.py
index 61d7f7b1..446e23c0 100644
--- a/rest_framework/tests/files.py
+++ b/rest_framework/tests/files.py
@@ -1,34 +1,51 @@
-# from django.test import TestCase
-# from django import forms
+import StringIO
+import datetime
 
-# from django.test.client import RequestFactory
-# from rest_framework.views import View
-# from rest_framework.response import Response
+from django.test import TestCase
 
-# import StringIO
+from rest_framework import serializers
 
 
-# class UploadFilesTests(TestCase):
-#     """Check uploading of files"""
-#     def setUp(self):
-#         self.factory = RequestFactory()
+class UploadedFile(object):
+    def __init__(self, file, created=None):
+        self.file = file
+        self.created = created or datetime.datetime.now()
 
-#     def test_upload_file(self):
 
-#         class FileForm(forms.Form):
-#             file = forms.FileField()
+class UploadedFileSerializer(serializers.Serializer):
+    file = serializers.FileField()
+    created = serializers.DateTimeField()
 
-#         class MockView(View):
-#             permissions = ()
-#             form = FileForm
+    def restore_object(self, attrs, instance=None):
+        if instance:
+            instance.file = attrs['file']
+            instance.created = attrs['created']
+            return instance
+        return UploadedFile(**attrs)
 
-#             def post(self, request, *args, **kwargs):
-#                 return Response({'FILE_NAME': self.CONTENT['file'].name,
-#                         'FILE_CONTENT': self.CONTENT['file'].read()})
 
-#         file = StringIO.StringIO('stuff')
-#         file.name = 'stuff.txt'
-#         request = self.factory.post('/', {'file': file})
-#         view = MockView.as_view()
-#         response = view(request)
-#         self.assertEquals(response.raw_content, {"FILE_CONTENT": "stuff", "FILE_NAME": "stuff.txt"})
+class FileSerializerTests(TestCase):
+    def test_create(self):
+        now = datetime.datetime.now()
+        file = StringIO.StringIO('stuff')
+        file.name = 'stuff.txt'
+        file.size = file.len
+        serializer = UploadedFileSerializer(data={'created': now}, files={'file': file})
+        uploaded_file = UploadedFile(file=file, created=now)
+        self.assertTrue(serializer.is_valid())
+        self.assertEquals(serializer.object.created, uploaded_file.created)
+        self.assertEquals(serializer.object.file, uploaded_file.file)
+        self.assertFalse(serializer.object is uploaded_file)
+
+    def test_creation_failure(self):
+        """
+        Passing files=None should result in an ValidationError
+
+        Regression test for:
+        https://github.com/tomchristie/django-rest-framework/issues/542
+        """
+        now = datetime.datetime.now()
+
+        serializer = UploadedFileSerializer(data={'created': now})
+        self.assertFalse(serializer.is_valid())
+        self.assertIn('file', serializer.errors)
diff --git a/rest_framework/tests/generics.py b/rest_framework/tests/generics.py
index a8279ef2..4799a04b 100644
--- a/rest_framework/tests/generics.py
+++ b/rest_framework/tests/generics.py
@@ -1,7 +1,8 @@
+import json
+from django.db import models
 from django.test import TestCase
-from django.test.client import RequestFactory
-from django.utils import simplejson as json
 from rest_framework import generics, serializers, status
+from rest_framework.tests.utils import RequestFactory
 from rest_framework.tests.models import BasicModel, Comment, SlugBasedModel
 
 
@@ -174,6 +175,20 @@ class TestInstanceView(TestCase):
         content = {'text': 'foobar'}
         request = factory.put('/1', json.dumps(content),
                               content_type='application/json')
+        response = self.view(request, pk='1').render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        self.assertEquals(response.data, {'id': 1, 'text': 'foobar'})
+        updated = self.objects.get(id=1)
+        self.assertEquals(updated.text, 'foobar')
+
+    def test_patch_instance_view(self):
+        """
+        PATCH requests to RetrieveUpdateDestroyAPIView should update an object.
+        """
+        content = {'text': 'foobar'}
+        request = factory.patch('/1', json.dumps(content),
+                              content_type='application/json')
+
         response = self.view(request, pk=1).render()
         self.assertEquals(response.status_code, status.HTTP_200_OK)
         self.assertEquals(response.data, {'id': 1, 'text': 'foobar'})
@@ -301,3 +316,36 @@ class TestCreateModelWithAutoNowAddField(TestCase):
         self.assertEquals(response.status_code, status.HTTP_201_CREATED)
         created = self.objects.get(id=1)
         self.assertEquals(created.content, 'foobar')
+
+
+# Test for particularly ugly reression with m2m in browseable API
+class ClassB(models.Model):
+    name = models.CharField(max_length=255)
+
+
+class ClassA(models.Model):
+    name = models.CharField(max_length=255)
+    childs = models.ManyToManyField(ClassB, blank=True, null=True)
+
+
+class ClassASerializer(serializers.ModelSerializer):
+    childs = serializers.ManyPrimaryKeyRelatedField(source='childs')
+
+    class Meta:
+        model = ClassA
+
+
+class ExampleView(generics.ListCreateAPIView):
+    serializer_class = ClassASerializer
+    model = ClassA
+
+
+class TestM2MBrowseableAPI(TestCase):
+    def test_m2m_in_browseable_api(self):
+        """
+        Test for particularly ugly reression with m2m in browseable API
+        """
+        request = factory.get('/', HTTP_ACCEPT='text/html')
+        view = ExampleView().as_view()
+        response = view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
diff --git a/rest_framework/tests/htmlrenderer.py b/rest_framework/tests/htmlrenderer.py
index 4caed59e..54096206 100644
--- a/rest_framework/tests/htmlrenderer.py
+++ b/rest_framework/tests/htmlrenderer.py
@@ -1,9 +1,9 @@
 from django.core.exceptions import PermissionDenied
-from django.conf.urls.defaults import patterns, url
 from django.http import Http404
 from django.test import TestCase
 from django.template import TemplateDoesNotExist, Template
 import django.template.loader
+from rest_framework.compat import patterns, url
 from rest_framework.decorators import api_view, renderer_classes
 from rest_framework.renderers import TemplateHTMLRenderer
 from rest_framework.response import Response
diff --git a/rest_framework/tests/hyperlinkedserializers.py b/rest_framework/tests/hyperlinkedserializers.py
index f71e2e28..c6a8224b 100644
--- a/rest_framework/tests/hyperlinkedserializers.py
+++ b/rest_framework/tests/hyperlinkedserializers.py
@@ -1,19 +1,21 @@
-from django.conf.urls.defaults import patterns, url
+import json
 from django.test import TestCase
 from django.test.client import RequestFactory
 from rest_framework import generics, status, serializers
-from rest_framework.tests.models import Anchor, BasicModel, ManyToManyModel, BlogPost, BlogPostComment, Album, Photo
+from rest_framework.compat import patterns, url
+from rest_framework.tests.models import Anchor, BasicModel, ManyToManyModel, BlogPost, BlogPostComment, Album, Photo, OptionalRelationModel
 
 factory = RequestFactory()
 
 
 class BlogPostCommentSerializer(serializers.ModelSerializer):
+    url = serializers.HyperlinkedIdentityField(view_name='blogpostcomment-detail')
     text = serializers.CharField()
     blog_post_url = serializers.HyperlinkedRelatedField(source='blog_post', view_name='blogpost-detail')
 
     class Meta:
         model = BlogPostComment
-        fields = ('text', 'blog_post_url')
+        fields = ('text', 'blog_post_url', 'url')
 
 
 class PhotoSerializer(serializers.Serializer):
@@ -54,6 +56,11 @@ class BlogPostCommentListCreate(generics.ListCreateAPIView):
     serializer_class = BlogPostCommentSerializer
 
 
+class BlogPostCommentDetail(generics.RetrieveAPIView):
+    model = BlogPostComment
+    serializer_class = BlogPostCommentSerializer
+
+
 class BlogPostDetail(generics.RetrieveAPIView):
     model = BlogPost
 
@@ -67,6 +74,11 @@ class AlbumDetail(generics.RetrieveAPIView):
     model = Album
 
 
+class OptionalRelationDetail(generics.RetrieveUpdateDestroyAPIView):
+    model = OptionalRelationModel
+    model_serializer_class = serializers.HyperlinkedModelSerializer
+
+
 urlpatterns = patterns('',
     url(r'^basic/$', BasicList.as_view(), name='basicmodel-list'),
     url(r'^basic/(?P<pk>\d+)/$', BasicDetail.as_view(), name='basicmodel-detail'),
@@ -75,8 +87,10 @@ urlpatterns = patterns('',
     url(r'^manytomany/(?P<pk>\d+)/$', ManyToManyDetail.as_view(), name='manytomanymodel-detail'),
     url(r'^posts/(?P<pk>\d+)/$', BlogPostDetail.as_view(), name='blogpost-detail'),
     url(r'^comments/$', BlogPostCommentListCreate.as_view(), name='blogpostcomment-list'),
+    url(r'^comments/(?P<pk>\d+)/$', BlogPostCommentDetail.as_view(), name='blogpostcomment-detail'),
     url(r'^albums/(?P<title>\w[\w-]*)/$', AlbumDetail.as_view(), name='album-detail'),
-    url(r'^photos/$', PhotoListCreate.as_view(), name='photo-list')
+    url(r'^photos/$', PhotoListCreate.as_view(), name='photo-list'),
+    url(r'^optionalrelation/(?P<pk>\d+)/$', OptionalRelationDetail.as_view(), name='optionalrelationmodel-detail'),
 )
 
 
@@ -151,7 +165,7 @@ class TestManyToManyHyperlinkedView(TestCase):
         GET requests to ListCreateAPIView should return list of objects.
         """
         request = factory.get('/manytomany/')
-        response = self.list_view(request).render()
+        response = self.list_view(request)
         self.assertEquals(response.status_code, status.HTTP_200_OK)
         self.assertEquals(response.data, self.data)
 
@@ -160,7 +174,7 @@ class TestManyToManyHyperlinkedView(TestCase):
         GET requests to ListCreateAPIView should return list of objects.
         """
         request = factory.get('/manytomany/1/')
-        response = self.detail_view(request, pk=1).render()
+        response = self.detail_view(request, pk=1)
         self.assertEquals(response.status_code, status.HTTP_200_OK)
         self.assertEquals(response.data, self.data[0])
 
@@ -183,8 +197,9 @@ class TestCreateWithForeignKeys(TestCase):
         }
 
         request = factory.post('/comments/', data=data)
-        response = self.create_view(request).render()
+        response = self.create_view(request)
         self.assertEqual(response.status_code, status.HTTP_201_CREATED)
+        self.assertEqual(response['Location'], 'http://testserver/comments/1/')
         self.assertEqual(self.post.blogpostcomment_set.count(), 1)
         self.assertEqual(self.post.blogpostcomment_set.all()[0].text, 'A test comment')
 
@@ -207,7 +222,41 @@ class TestCreateWithForeignKeysAndCustomSlug(TestCase):
         }
 
         request = factory.post('/photos/', data=data)
-        response = self.list_create_view(request).render()
+        response = self.list_create_view(request)
         self.assertEqual(response.status_code, status.HTTP_201_CREATED)
+        self.assertNotIn('Location', response, msg='Location should only be included if there is a "url" field on the serializer')
         self.assertEqual(self.post.photo_set.count(), 1)
         self.assertEqual(self.post.photo_set.all()[0].description, 'A test photo')
+
+
+class TestOptionalRelationHyperlinkedView(TestCase):
+    urls = 'rest_framework.tests.hyperlinkedserializers'
+
+    def setUp(self):
+        """
+        Create 1 OptionalRelationModel intances.
+        """
+        OptionalRelationModel().save()
+        self.objects = OptionalRelationModel.objects
+        self.detail_view = OptionalRelationDetail.as_view()
+        self.data = {"url": "http://testserver/optionalrelation/1/", "other": None}
+
+    def test_get_detail_view(self):
+        """
+        GET requests to RetrieveAPIView with optional relations should return None
+        for non existing relations.
+        """
+        request = factory.get('/optionalrelationmodel-detail/1')
+        response = self.detail_view(request, pk=1)
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        self.assertEquals(response.data, self.data)
+
+    def test_put_detail_view(self):
+        """
+        PUT requests to RetrieveUpdateDestroyAPIView with optional relations
+        should accept None for non existing relations.
+        """
+        response = self.client.put('/optionalrelation/1/',
+                                   data=json.dumps(self.data),
+                                   content_type='application/json')
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
diff --git a/rest_framework/tests/models.py b/rest_framework/tests/models.py
index a2aba5be..59c35074 100644
--- a/rest_framework/tests/models.py
+++ b/rest_framework/tests/models.py
@@ -35,6 +35,13 @@ def foobar():
     return 'foobar'
 
 
+class CustomField(models.CharField):
+
+    def __init__(self, *args, **kwargs):
+        kwargs['max_length'] = 12
+        super(CustomField, self).__init__(*args, **kwargs)
+
+
 class RESTFrameworkModel(models.Model):
     """
     Base for test models that sets app_label, so they play nicely.
@@ -44,6 +51,11 @@ class RESTFrameworkModel(models.Model):
         abstract = True
 
 
+class HasPositiveIntegerAsChoice(RESTFrameworkModel):
+    some_choices = ((1, 'A'), (2, 'B'), (3, 'C'))
+    some_integer = models.PositiveIntegerField(choices=some_choices)
+
+
 class Anchor(RESTFrameworkModel):
     text = models.CharField(max_length=100, default='anchor')
 
@@ -59,6 +71,7 @@ class SlugBasedModel(RESTFrameworkModel):
 
 class DefaultValueModel(RESTFrameworkModel):
     text = models.CharField(default='foobar', max_length=100)
+    extra = models.CharField(blank=True, null=True, max_length=100)
 
 
 class CallableDefaultValueModel(RESTFrameworkModel):
@@ -113,11 +126,28 @@ class Comment(RESTFrameworkModel):
 class ActionItem(RESTFrameworkModel):
     title = models.CharField(max_length=200)
     done = models.BooleanField(default=False)
+    info = CustomField(default='---', max_length=12)
 
 
 # Models for reverse relations
+class Person(RESTFrameworkModel):
+    name = models.CharField(max_length=10)
+    age = models.IntegerField(null=True, blank=True)
+
+    @property
+    def info(self):
+        return {
+            'name': self.name,
+            'age': self.age,
+        }
+
+
 class BlogPost(RESTFrameworkModel):
     title = models.CharField(max_length=100)
+    writer = models.ForeignKey(Person, null=True, blank=True)
+
+    def get_first_comment(self):
+        return self.blogpostcomment_set.all()[0]
 
 
 class BlogPostComment(RESTFrameworkModel):
@@ -134,18 +164,44 @@ class Photo(RESTFrameworkModel):
     album = models.ForeignKey(Album)
 
 
-class Person(RESTFrameworkModel):
-    name = models.CharField(max_length=10)
-    age = models.IntegerField(null=True, blank=True)
+# Model for issue #324
+class BlankFieldModel(RESTFrameworkModel):
+    title = models.CharField(max_length=100, blank=True, null=False)
 
-    @property
-    def info(self):
-        return {
-            'name': self.name,
-            'age': self.age,
-        }
 
+# Model for issue #380
+class OptionalRelationModel(RESTFrameworkModel):
+    other = models.ForeignKey('OptionalRelationModel', blank=True, null=True)
 
-# Model for issue #324
-class BlankFieldModel(RESTFrameworkModel):
-    title = models.CharField(max_length=100, blank=True)
+
+# Model for RegexField
+class Book(RESTFrameworkModel):
+    isbn = models.CharField(max_length=13)
+
+
+# Models for relations tests
+# ManyToMany
+class ManyToManyTarget(RESTFrameworkModel):
+    name = models.CharField(max_length=100)
+
+
+class ManyToManySource(RESTFrameworkModel):
+    name = models.CharField(max_length=100)
+    targets = models.ManyToManyField(ManyToManyTarget, related_name='sources')
+
+
+# ForeignKey
+class ForeignKeyTarget(RESTFrameworkModel):
+    name = models.CharField(max_length=100)
+
+
+class ForeignKeySource(RESTFrameworkModel):
+    name = models.CharField(max_length=100)
+    target = models.ForeignKey(ForeignKeyTarget, related_name='sources')
+
+
+# Nullable ForeignKey
+class NullableForeignKeySource(RESTFrameworkModel):
+    name = models.CharField(max_length=100)
+    target = models.ForeignKey(ForeignKeyTarget, null=True, blank=True,
+                               related_name='nullable_sources')
diff --git a/rest_framework/tests/modelviews.py b/rest_framework/tests/modelviews.py
index 1f8468e8..f12e3b97 100644
--- a/rest_framework/tests/modelviews.py
+++ b/rest_framework/tests/modelviews.py
@@ -1,4 +1,4 @@
-# from django.conf.urls.defaults import patterns, url
+# from rest_framework.compat import patterns, url
 # from django.forms import ModelForm
 # from django.contrib.auth.models import Group, User
 # from rest_framework.resources import ModelResource
diff --git a/rest_framework/tests/pagination.py b/rest_framework/tests/pagination.py
index 713a7255..81d297a1 100644
--- a/rest_framework/tests/pagination.py
+++ b/rest_framework/tests/pagination.py
@@ -4,7 +4,7 @@ from django.core.paginator import Paginator
 from django.test import TestCase
 from django.test.client import RequestFactory
 from django.utils import unittest
-from rest_framework import generics, status, pagination, filters
+from rest_framework import generics, status, pagination, filters, serializers
 from rest_framework.compat import django_filters
 from rest_framework.tests.models import BasicModel, FilterableItem
 
@@ -34,6 +34,21 @@ if django_filters:
         filter_backend = filters.DjangoFilterBackend
 
 
+class DefaultPageSizeKwargView(generics.ListAPIView):
+    """
+    View for testing default paginate_by_param usage
+    """
+    model = BasicModel
+
+
+class PaginateByParamView(generics.ListAPIView):
+    """
+    View for testing custom paginate_by_param usage
+    """
+    model = BasicModel
+    paginate_by_param = 'page_size'
+
+
 class IntegrationTestPagination(TestCase):
     """
     Integration tests for paginated list views.
@@ -133,9 +148,14 @@ class IntegrationTestPaginationAndFiltering(TestCase):
         self.assertEquals(response.data['previous'], None)
 
 
+class PassOnContextPaginationSerializer(pagination.PaginationSerializer):
+    class Meta:
+        object_serializer_class = serializers.Serializer
+
+
 class UnitTestPagination(TestCase):
     """
-    Unit tests for pagination of primative objects.
+    Unit tests for pagination of primitive objects.
     """
 
     def setUp(self):
@@ -156,3 +176,106 @@ class UnitTestPagination(TestCase):
         self.assertEquals(serializer.data['next'], None)
         self.assertEquals(serializer.data['previous'], '?page=2')
         self.assertEquals(serializer.data['results'], self.objects[20:])
+
+    def test_context_available_in_result(self):
+        """
+        Ensure context gets passed through to the object serializer.
+        """
+        serializer = PassOnContextPaginationSerializer(self.first_page)
+        serializer.data
+        results = serializer.fields[serializer.results_field]
+        self.assertTrue(serializer.context is results.context)
+
+
+class TestUnpaginated(TestCase):
+    """
+    Tests for list views without pagination.
+    """
+
+    def setUp(self):
+        """
+        Create 13 BasicModel instances.
+        """
+        for i in range(13):
+            BasicModel(text=i).save()
+        self.objects = BasicModel.objects
+        self.data = [
+        {'id': obj.id, 'text': obj.text}
+        for obj in self.objects.all()
+        ]
+        self.view = DefaultPageSizeKwargView.as_view()
+
+    def test_unpaginated(self):
+        """
+        Tests the default page size for this view.
+        no page size --> no limit --> no meta data
+        """
+        request = factory.get('/')
+        response = self.view(request)
+        self.assertEquals(response.data, self.data)
+
+
+class TestCustomPaginateByParam(TestCase):
+    """
+    Tests for list views with default page size kwarg
+    """
+
+    def setUp(self):
+        """
+        Create 13 BasicModel instances.
+        """
+        for i in range(13):
+            BasicModel(text=i).save()
+        self.objects = BasicModel.objects
+        self.data = [
+        {'id': obj.id, 'text': obj.text}
+        for obj in self.objects.all()
+        ]
+        self.view = PaginateByParamView.as_view()
+
+    def test_default_page_size(self):
+        """
+        Tests the default page size for this view.
+        no page size --> no limit --> no meta data
+        """
+        request = factory.get('/')
+        response = self.view(request).render()
+        self.assertEquals(response.data, self.data)
+
+    def test_paginate_by_param(self):
+        """
+        If paginate_by_param is set, the new kwarg should limit per view requests.
+        """
+        request = factory.get('/?page_size=5')
+        response = self.view(request).render()
+        self.assertEquals(response.data['count'], 13)
+        self.assertEquals(response.data['results'], self.data[:5])
+
+
+class CustomField(serializers.Field):
+    def to_native(self, value):
+        if not 'view' in self.context:
+            raise RuntimeError("context isn't getting passed into custom field")
+        return "value"
+
+
+class BasicModelSerializer(serializers.Serializer):
+    text = CustomField()
+
+
+class TestContextPassedToCustomField(TestCase):
+    def setUp(self):
+        BasicModel.objects.create(text='ala ma kota')
+
+    def test_with_pagination(self):
+        class ListView(generics.ListCreateAPIView):
+            model = BasicModel
+            serializer_class = BasicModelSerializer
+            paginate_by = 1
+
+        self.view = ListView.as_view()
+        request = factory.get('/')
+        response = self.view(request).render()
+
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+
diff --git a/rest_framework/tests/pk_relations.py b/rest_framework/tests/pk_relations.py
deleted file mode 100644
index 44ae4040..00000000
--- a/rest_framework/tests/pk_relations.py
+++ /dev/null
@@ -1,205 +0,0 @@
-from django.db import models
-from django.test import TestCase
-from rest_framework import serializers
-
-
-# ManyToMany
-
-class ManyToManyTarget(models.Model):
-    name = models.CharField(max_length=100)
-
-
-class ManyToManySource(models.Model):
-    name = models.CharField(max_length=100)
-    targets = models.ManyToManyField(ManyToManyTarget, related_name='sources')
-
-
-class ManyToManyTargetSerializer(serializers.ModelSerializer):
-    sources = serializers.ManyPrimaryKeyRelatedField()
-
-    class Meta:
-        model = ManyToManyTarget
-
-
-class ManyToManySourceSerializer(serializers.ModelSerializer):
-    class Meta:
-        model = ManyToManySource
-
-
-# ForeignKey
-
-class ForeignKeyTarget(models.Model):
-    name = models.CharField(max_length=100)
-
-
-class ForeignKeySource(models.Model):
-    name = models.CharField(max_length=100)
-    target = models.ForeignKey(ForeignKeyTarget, related_name='sources')
-
-
-class ForeignKeyTargetSerializer(serializers.ModelSerializer):
-    sources = serializers.ManyPrimaryKeyRelatedField(read_only=True)
-
-    class Meta:
-        model = ForeignKeyTarget
-
-
-class ForeignKeySourceSerializer(serializers.ModelSerializer):
-    class Meta:
-        model = ForeignKeySource
-
-
-# TODO: Add test that .data cannot be accessed prior to .is_valid
-
-class PrimaryKeyManyToManyTests(TestCase):
-    def setUp(self):
-        for idx in range(1, 4):
-            target = ManyToManyTarget(name='target-%d' % idx)
-            target.save()
-            source = ManyToManySource(name='source-%d' % idx)
-            source.save()
-            for target in ManyToManyTarget.objects.all():
-                source.targets.add(target)
-
-    def test_many_to_many_retrieve(self):
-        queryset = ManyToManySource.objects.all()
-        serializer = ManyToManySourceSerializer(queryset)
-        expected = [
-                {'id': 1, 'name': u'source-1', 'targets': [1]},
-                {'id': 2, 'name': u'source-2', 'targets': [1, 2]},
-                {'id': 3, 'name': u'source-3', 'targets': [1, 2, 3]}
-        ]
-        self.assertEquals(serializer.data, expected)
-
-    def test_reverse_many_to_many_retrieve(self):
-        queryset = ManyToManyTarget.objects.all()
-        serializer = ManyToManyTargetSerializer(queryset)
-        expected = [
-            {'id': 1, 'name': u'target-1', 'sources': [1, 2, 3]},
-            {'id': 2, 'name': u'target-2', 'sources': [2, 3]},
-            {'id': 3, 'name': u'target-3', 'sources': [3]}
-        ]
-        self.assertEquals(serializer.data, expected)
-
-    def test_many_to_many_update(self):
-        data = {'id': 1, 'name': u'source-1', 'targets': [1, 2, 3]}
-        instance = ManyToManySource.objects.get(pk=1)
-        serializer = ManyToManySourceSerializer(instance, data=data)
-        self.assertTrue(serializer.is_valid())
-        self.assertEquals(serializer.data, data)
-        serializer.save()
-
-        # Ensure source 1 is updated, and everything else is as expected
-        queryset = ManyToManySource.objects.all()
-        serializer = ManyToManySourceSerializer(queryset)
-        expected = [
-                {'id': 1, 'name': u'source-1', 'targets': [1, 2, 3]},
-                {'id': 2, 'name': u'source-2', 'targets': [1, 2]},
-                {'id': 3, 'name': u'source-3', 'targets': [1, 2, 3]}
-        ]
-        self.assertEquals(serializer.data, expected)
-
-    def test_reverse_many_to_many_update(self):
-        data = {'id': 1, 'name': u'target-1', 'sources': [1]}
-        instance = ManyToManyTarget.objects.get(pk=1)
-        serializer = ManyToManyTargetSerializer(instance, data=data)
-        self.assertTrue(serializer.is_valid())
-        self.assertEquals(serializer.data, data)
-        serializer.save()
-
-        # Ensure target 1 is updated, and everything else is as expected
-        queryset = ManyToManyTarget.objects.all()
-        serializer = ManyToManyTargetSerializer(queryset)
-        expected = [
-            {'id': 1, 'name': u'target-1', 'sources': [1]},
-            {'id': 2, 'name': u'target-2', 'sources': [2, 3]},
-            {'id': 3, 'name': u'target-3', 'sources': [3]}
-        ]
-        self.assertEquals(serializer.data, expected)
-
-    def test_reverse_many_to_many_create(self):
-        data = {'id': 4, 'name': u'target-4', 'sources': [1, 3]}
-        serializer = ManyToManyTargetSerializer(data=data)
-        self.assertTrue(serializer.is_valid())
-        obj = serializer.save()
-        self.assertEquals(serializer.data, data)
-        self.assertEqual(obj.name, u'target-4')
-
-        # Ensure target 4 is added, and everything else is as expected
-        queryset = ManyToManyTarget.objects.all()
-        serializer = ManyToManyTargetSerializer(queryset)
-        expected = [
-            {'id': 1, 'name': u'target-1', 'sources': [1, 2, 3]},
-            {'id': 2, 'name': u'target-2', 'sources': [2, 3]},
-            {'id': 3, 'name': u'target-3', 'sources': [3]},
-            {'id': 4, 'name': u'target-4', 'sources': [1, 3]}
-        ]
-        self.assertEquals(serializer.data, expected)
-
-class PrimaryKeyForeignKeyTests(TestCase):
-    def setUp(self):
-        target = ForeignKeyTarget(name='target-1')
-        target.save()
-        new_target = ForeignKeyTarget(name='target-2')
-        new_target.save()
-        for idx in range(1, 4):
-            source = ForeignKeySource(name='source-%d' % idx, target=target)
-            source.save()
-
-    def test_foreign_key_retrieve(self):
-        queryset = ForeignKeySource.objects.all()
-        serializer = ForeignKeySourceSerializer(queryset)
-        expected = [
-            {'id': 1, 'name': u'source-1', 'target': 1},
-            {'id': 2, 'name': u'source-2', 'target': 1},
-            {'id': 3, 'name': u'source-3', 'target': 1}
-        ]
-        self.assertEquals(serializer.data, expected)
-
-    def test_reverse_foreign_key_retrieve(self):
-        queryset = ForeignKeyTarget.objects.all()
-        serializer = ForeignKeyTargetSerializer(queryset)
-        expected = [
-            {'id': 1, 'name': u'target-1', 'sources': [1, 2, 3]},
-            {'id': 2, 'name': u'target-2', 'sources': []},
-        ]
-        self.assertEquals(serializer.data, expected)
-
-    def test_foreign_key_update(self):
-        data = {'id': 1, 'name': u'source-1', 'target': 2}
-        instance = ForeignKeySource.objects.get(pk=1)
-        serializer = ForeignKeySourceSerializer(instance, data=data)
-        self.assertTrue(serializer.is_valid())
-        self.assertEquals(serializer.data, data)
-        serializer.save()
-
-        # # Ensure source 1 is updated, and everything else is as expected
-        queryset = ForeignKeySource.objects.all()
-        serializer = ForeignKeySourceSerializer(queryset)
-        expected = [
-            {'id': 1, 'name': u'source-1', 'target': 2},
-            {'id': 2, 'name': u'source-2', 'target': 1},
-            {'id': 3, 'name': u'source-3', 'target': 1}
-        ]
-        self.assertEquals(serializer.data, expected)
-
-    # reverse foreign keys MUST be read_only
-    # In the general case they do not provide .remove() or .clear()
-    # and cannot be arbitrarily set.
-
-    # def test_reverse_foreign_key_update(self):
-    #     data = {'id': 1, 'name': u'target-1', 'sources': [1]}
-    #     instance = ForeignKeyTarget.objects.get(pk=1)
-    #     serializer = ForeignKeyTargetSerializer(instance, data=data)
-    #     self.assertTrue(serializer.is_valid())
-    #     self.assertEquals(serializer.data, data)
-    #     serializer.save()
-
-    #     # Ensure target 1 is updated, and everything else is as expected
-    #     queryset = ForeignKeyTarget.objects.all()
-    #     serializer = ForeignKeyTargetSerializer(queryset)
-    #     expected = [
-    #         {'id': 1, 'name': u'target-1', 'sources': [1]},
-    #         {'id': 2, 'name': u'target-2', 'sources': []},
-    #     ]
-    #     self.assertEquals(serializer.data, expected)
diff --git a/rest_framework/tests/relations.py b/rest_framework/tests/relations.py
new file mode 100644
index 00000000..91daea8a
--- /dev/null
+++ b/rest_framework/tests/relations.py
@@ -0,0 +1,33 @@
+"""
+General tests for relational fields.
+"""
+
+from django.db import models
+from django.test import TestCase
+from rest_framework import serializers
+
+
+class NullModel(models.Model):
+    pass
+
+
+class FieldTests(TestCase):
+    def test_pk_related_field_with_empty_string(self):
+        """
+        Regression test for #446
+
+        https://github.com/tomchristie/django-rest-framework/issues/446
+        """
+        field = serializers.PrimaryKeyRelatedField(queryset=NullModel.objects.all())
+        self.assertRaises(serializers.ValidationError, field.from_native, '')
+        self.assertRaises(serializers.ValidationError, field.from_native, [])
+
+    def test_hyperlinked_related_field_with_empty_string(self):
+        field = serializers.HyperlinkedRelatedField(queryset=NullModel.objects.all(), view_name='')
+        self.assertRaises(serializers.ValidationError, field.from_native, '')
+        self.assertRaises(serializers.ValidationError, field.from_native, [])
+
+    def test_slug_related_field_with_empty_string(self):
+        field = serializers.SlugRelatedField(queryset=NullModel.objects.all(), slug_field='pk')
+        self.assertRaises(serializers.ValidationError, field.from_native, '')
+        self.assertRaises(serializers.ValidationError, field.from_native, [])
diff --git a/rest_framework/tests/relations_hyperlink.py b/rest_framework/tests/relations_hyperlink.py
new file mode 100644
index 00000000..a7f8a035
--- /dev/null
+++ b/rest_framework/tests/relations_hyperlink.py
@@ -0,0 +1,411 @@
+from django.db import models
+from django.test import TestCase
+from rest_framework import serializers
+from rest_framework.compat import patterns, url
+from rest_framework.tests.models import ManyToManyTarget, ManyToManySource, ForeignKeyTarget, ForeignKeySource
+
+def dummy_view(request, pk):
+    pass
+
+urlpatterns = patterns('',
+    url(r'^manytomanysource/(?P<pk>[0-9]+)/$', dummy_view, name='manytomanysource-detail'),
+    url(r'^manytomanytarget/(?P<pk>[0-9]+)/$', dummy_view, name='manytomanytarget-detail'),
+    url(r'^foreignkeysource/(?P<pk>[0-9]+)/$', dummy_view, name='foreignkeysource-detail'),
+    url(r'^foreignkeytarget/(?P<pk>[0-9]+)/$', dummy_view, name='foreignkeytarget-detail'),
+    url(r'^nullableforeignkeysource/(?P<pk>[0-9]+)/$', dummy_view, name='nullableforeignkeysource-detail'),
+)
+
+class ManyToManyTargetSerializer(serializers.HyperlinkedModelSerializer):
+    sources = serializers.ManyHyperlinkedRelatedField(view_name='manytomanysource-detail')
+
+    class Meta:
+        model = ManyToManyTarget
+
+
+class ManyToManySourceSerializer(serializers.HyperlinkedModelSerializer):
+    class Meta:
+        model = ManyToManySource
+
+
+class ForeignKeyTargetSerializer(serializers.HyperlinkedModelSerializer):
+    sources = serializers.ManyHyperlinkedRelatedField(view_name='foreignkeysource-detail')
+
+    class Meta:
+        model = ForeignKeyTarget
+
+
+class ForeignKeySourceSerializer(serializers.HyperlinkedModelSerializer):
+    class Meta:
+        model = ForeignKeySource
+
+
+# Nullable ForeignKey
+
+class NullableForeignKeySource(models.Model):
+    name = models.CharField(max_length=100)
+    target = models.ForeignKey(ForeignKeyTarget, null=True, blank=True,
+                               related_name='nullable_sources')
+
+
+class NullableForeignKeySourceSerializer(serializers.HyperlinkedModelSerializer):
+    class Meta:
+        model = NullableForeignKeySource
+
+
+# TODO: Add test that .data cannot be accessed prior to .is_valid
+
+class HyperlinkedManyToManyTests(TestCase):
+    urls = 'rest_framework.tests.relations_hyperlink'
+
+    def setUp(self):
+        for idx in range(1, 4):
+            target = ManyToManyTarget(name='target-%d' % idx)
+            target.save()
+            source = ManyToManySource(name='source-%d' % idx)
+            source.save()
+            for target in ManyToManyTarget.objects.all():
+                source.targets.add(target)
+
+    def test_many_to_many_retrieve(self):
+        queryset = ManyToManySource.objects.all()
+        serializer = ManyToManySourceSerializer(queryset)
+        expected = [
+                {'url': '/manytomanysource/1/', 'name': u'source-1', 'targets': ['/manytomanytarget/1/']},
+                {'url': '/manytomanysource/2/', 'name': u'source-2', 'targets': ['/manytomanytarget/1/', '/manytomanytarget/2/']},
+                {'url': '/manytomanysource/3/', 'name': u'source-3', 'targets': ['/manytomanytarget/1/', '/manytomanytarget/2/', '/manytomanytarget/3/']}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_many_to_many_retrieve(self):
+        queryset = ManyToManyTarget.objects.all()
+        serializer = ManyToManyTargetSerializer(queryset)
+        expected = [
+            {'url': '/manytomanytarget/1/', 'name': u'target-1', 'sources': ['/manytomanysource/1/', '/manytomanysource/2/', '/manytomanysource/3/']},
+            {'url': '/manytomanytarget/2/', 'name': u'target-2', 'sources': ['/manytomanysource/2/', '/manytomanysource/3/']},
+            {'url': '/manytomanytarget/3/', 'name': u'target-3', 'sources': ['/manytomanysource/3/']}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_many_to_many_update(self):
+        data = {'url': '/manytomanysource/1/', 'name': u'source-1', 'targets': ['/manytomanytarget/1/', '/manytomanytarget/2/', '/manytomanytarget/3/']}
+        instance = ManyToManySource.objects.get(pk=1)
+        serializer = ManyToManySourceSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        serializer.save()
+        self.assertEquals(serializer.data, data)
+
+        # Ensure source 1 is updated, and everything else is as expected
+        queryset = ManyToManySource.objects.all()
+        serializer = ManyToManySourceSerializer(queryset)
+        expected = [
+                {'url': '/manytomanysource/1/', 'name': u'source-1', 'targets': ['/manytomanytarget/1/', '/manytomanytarget/2/', '/manytomanytarget/3/']},
+                {'url': '/manytomanysource/2/', 'name': u'source-2', 'targets': ['/manytomanytarget/1/', '/manytomanytarget/2/']},
+                {'url': '/manytomanysource/3/', 'name': u'source-3', 'targets': ['/manytomanytarget/1/', '/manytomanytarget/2/', '/manytomanytarget/3/']}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_many_to_many_update(self):
+        data = {'url': '/manytomanytarget/1/', 'name': u'target-1', 'sources': ['/manytomanysource/1/']}
+        instance = ManyToManyTarget.objects.get(pk=1)
+        serializer = ManyToManyTargetSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        serializer.save()
+        self.assertEquals(serializer.data, data)
+
+        # Ensure target 1 is updated, and everything else is as expected
+        queryset = ManyToManyTarget.objects.all()
+        serializer = ManyToManyTargetSerializer(queryset)
+        expected = [
+            {'url': '/manytomanytarget/1/', 'name': u'target-1', 'sources': ['/manytomanysource/1/']},
+            {'url': '/manytomanytarget/2/', 'name': u'target-2', 'sources': ['/manytomanysource/2/', '/manytomanysource/3/']},
+            {'url': '/manytomanytarget/3/', 'name': u'target-3', 'sources': ['/manytomanysource/3/']}
+
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_many_to_many_create(self):
+        data = {'url': '/manytomanysource/4/', 'name': u'source-4', 'targets': ['/manytomanytarget/1/', '/manytomanytarget/3/']}
+        serializer = ManyToManySourceSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, data)
+        self.assertEqual(obj.name, u'source-4')
+
+        # Ensure source 4 is added, and everything else is as expected
+        queryset = ManyToManySource.objects.all()
+        serializer = ManyToManySourceSerializer(queryset)
+        expected = [
+            {'url': '/manytomanysource/1/', 'name': u'source-1', 'targets': ['/manytomanytarget/1/']},
+            {'url': '/manytomanysource/2/', 'name': u'source-2', 'targets': ['/manytomanytarget/1/', '/manytomanytarget/2/']},
+            {'url': '/manytomanysource/3/', 'name': u'source-3', 'targets': ['/manytomanytarget/1/', '/manytomanytarget/2/', '/manytomanytarget/3/']},
+            {'url': '/manytomanysource/4/', 'name': u'source-4', 'targets': ['/manytomanytarget/1/', '/manytomanytarget/3/']}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_many_to_many_create(self):
+        data = {'url': '/manytomanytarget/4/', 'name': u'target-4', 'sources': ['/manytomanysource/1/', '/manytomanysource/3/']}
+        serializer = ManyToManyTargetSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, data)
+        self.assertEqual(obj.name, u'target-4')
+
+        # Ensure target 4 is added, and everything else is as expected
+        queryset = ManyToManyTarget.objects.all()
+        serializer = ManyToManyTargetSerializer(queryset)
+        expected = [
+            {'url': '/manytomanytarget/1/', 'name': u'target-1', 'sources': ['/manytomanysource/1/', '/manytomanysource/2/', '/manytomanysource/3/']},
+            {'url': '/manytomanytarget/2/', 'name': u'target-2', 'sources': ['/manytomanysource/2/', '/manytomanysource/3/']},
+            {'url': '/manytomanytarget/3/', 'name': u'target-3', 'sources': ['/manytomanysource/3/']},
+            {'url': '/manytomanytarget/4/', 'name': u'target-4', 'sources': ['/manytomanysource/1/', '/manytomanysource/3/']}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+
+class HyperlinkedForeignKeyTests(TestCase):
+    urls = 'rest_framework.tests.relations_hyperlink'
+
+    def setUp(self):
+        target = ForeignKeyTarget(name='target-1')
+        target.save()
+        new_target = ForeignKeyTarget(name='target-2')
+        new_target.save()
+        for idx in range(1, 4):
+            source = ForeignKeySource(name='source-%d' % idx, target=target)
+            source.save()
+
+    def test_foreign_key_retrieve(self):
+        queryset = ForeignKeySource.objects.all()
+        serializer = ForeignKeySourceSerializer(queryset)
+        expected = [
+            {'url': '/foreignkeysource/1/', 'name': u'source-1', 'target': '/foreignkeytarget/1/'},
+            {'url': '/foreignkeysource/2/', 'name': u'source-2', 'target': '/foreignkeytarget/1/'},
+            {'url': '/foreignkeysource/3/', 'name': u'source-3', 'target': '/foreignkeytarget/1/'}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_foreign_key_retrieve(self):
+        queryset = ForeignKeyTarget.objects.all()
+        serializer = ForeignKeyTargetSerializer(queryset)
+        expected = [
+            {'url': '/foreignkeytarget/1/', 'name': u'target-1', 'sources': ['/foreignkeysource/1/', '/foreignkeysource/2/', '/foreignkeysource/3/']},
+            {'url': '/foreignkeytarget/2/', 'name': u'target-2', 'sources': []},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_update(self):
+        data = {'url': '/foreignkeysource/1/', 'name': u'source-1', 'target': '/foreignkeytarget/2/'}
+        instance = ForeignKeySource.objects.get(pk=1)
+        serializer = ForeignKeySourceSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        self.assertEquals(serializer.data, data)
+        serializer.save()
+
+        # Ensure source 1 is updated, and everything else is as expected
+        queryset = ForeignKeySource.objects.all()
+        serializer = ForeignKeySourceSerializer(queryset)
+        expected = [
+            {'url': '/foreignkeysource/1/', 'name': u'source-1', 'target': '/foreignkeytarget/2/'},
+            {'url': '/foreignkeysource/2/', 'name': u'source-2', 'target': '/foreignkeytarget/1/'},
+            {'url': '/foreignkeysource/3/', 'name': u'source-3', 'target': '/foreignkeytarget/1/'}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_foreign_key_update(self):
+        data = {'url': '/foreignkeytarget/2/', 'name': u'target-2', 'sources': ['/foreignkeysource/1/', '/foreignkeysource/3/']}
+        instance = ForeignKeyTarget.objects.get(pk=2)
+        serializer = ForeignKeyTargetSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        # We shouldn't have saved anything to the db yet since save
+        # hasn't been called.
+        queryset = ForeignKeyTarget.objects.all()
+        new_serializer = ForeignKeyTargetSerializer(queryset)
+        expected = [
+            {'url': '/foreignkeytarget/1/', 'name': u'target-1', 'sources': ['/foreignkeysource/1/', '/foreignkeysource/2/', '/foreignkeysource/3/']},
+            {'url': '/foreignkeytarget/2/', 'name': u'target-2', 'sources': []},
+        ]        
+        self.assertEquals(new_serializer.data, expected)
+
+        serializer.save()
+        self.assertEquals(serializer.data, data)
+
+        # Ensure target 2 is update, and everything else is as expected
+        queryset = ForeignKeyTarget.objects.all()
+        serializer = ForeignKeyTargetSerializer(queryset)
+        expected = [
+            {'url': '/foreignkeytarget/1/', 'name': u'target-1', 'sources': ['/foreignkeysource/2/']},
+            {'url': '/foreignkeytarget/2/', 'name': u'target-2', 'sources': ['/foreignkeysource/1/', '/foreignkeysource/3/']},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_create(self):
+        data = {'url': '/foreignkeysource/4/', 'name': u'source-4', 'target': '/foreignkeytarget/2/'}
+        serializer = ForeignKeySourceSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, data)
+        self.assertEqual(obj.name, u'source-4')
+
+        # Ensure source 1 is updated, and everything else is as expected
+        queryset = ForeignKeySource.objects.all()
+        serializer = ForeignKeySourceSerializer(queryset)
+        expected = [
+            {'url': '/foreignkeysource/1/', 'name': u'source-1', 'target': '/foreignkeytarget/1/'},
+            {'url': '/foreignkeysource/2/', 'name': u'source-2', 'target': '/foreignkeytarget/1/'},
+            {'url': '/foreignkeysource/3/', 'name': u'source-3', 'target': '/foreignkeytarget/1/'},
+            {'url': '/foreignkeysource/4/', 'name': u'source-4', 'target': '/foreignkeytarget/2/'},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_foreign_key_create(self):
+        data = {'url': '/foreignkeytarget/3/', 'name': u'target-3', 'sources': ['/foreignkeysource/1/', '/foreignkeysource/3/']}
+        serializer = ForeignKeyTargetSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, data)
+        self.assertEqual(obj.name, u'target-3')
+
+        # Ensure target 4 is added, and everything else is as expected
+        queryset = ForeignKeyTarget.objects.all()
+        serializer = ForeignKeyTargetSerializer(queryset)
+        expected = [
+            {'url': '/foreignkeytarget/1/', 'name': u'target-1', 'sources': ['/foreignkeysource/2/']},
+            {'url': '/foreignkeytarget/2/', 'name': u'target-2', 'sources': []},
+            {'url': '/foreignkeytarget/3/', 'name': u'target-3', 'sources': ['/foreignkeysource/1/', '/foreignkeysource/3/']},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_update_with_invalid_null(self):
+        data = {'url': '/foreignkeysource/1/', 'name': u'source-1', 'target': None}
+        instance = ForeignKeySource.objects.get(pk=1)
+        serializer = ForeignKeySourceSerializer(instance, data=data)
+        self.assertFalse(serializer.is_valid())
+        self.assertEquals(serializer.errors, {'target': [u'Value may not be null']})
+
+
+class HyperlinkedNullableForeignKeyTests(TestCase):
+    urls = 'rest_framework.tests.relations_hyperlink'
+
+    def setUp(self):
+        target = ForeignKeyTarget(name='target-1')
+        target.save()
+        for idx in range(1, 4):
+            if idx == 3:
+                target = None
+            source = NullableForeignKeySource(name='source-%d' % idx, target=target)
+            source.save()
+
+    def test_foreign_key_retrieve_with_null(self):
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'url': '/nullableforeignkeysource/1/', 'name': u'source-1', 'target': '/foreignkeytarget/1/'},
+            {'url': '/nullableforeignkeysource/2/', 'name': u'source-2', 'target': '/foreignkeytarget/1/'},
+            {'url': '/nullableforeignkeysource/3/', 'name': u'source-3', 'target': None},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_create_with_valid_null(self):
+        data = {'url': '/nullableforeignkeysource/4/', 'name': u'source-4', 'target': None}
+        serializer = NullableForeignKeySourceSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, data)
+        self.assertEqual(obj.name, u'source-4')
+
+        # Ensure source 4 is created, and everything else is as expected
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'url': '/nullableforeignkeysource/1/', 'name': u'source-1', 'target': '/foreignkeytarget/1/'},
+            {'url': '/nullableforeignkeysource/2/', 'name': u'source-2', 'target': '/foreignkeytarget/1/'},
+            {'url': '/nullableforeignkeysource/3/', 'name': u'source-3', 'target': None},
+            {'url': '/nullableforeignkeysource/4/', 'name': u'source-4', 'target': None}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_create_with_valid_emptystring(self):
+        """
+        The emptystring should be interpreted as null in the context
+        of relationships.
+        """
+        data = {'url': '/nullableforeignkeysource/4/', 'name': u'source-4', 'target': ''}
+        expected_data = {'url': '/nullableforeignkeysource/4/', 'name': u'source-4', 'target': None}
+        serializer = NullableForeignKeySourceSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, expected_data)
+        self.assertEqual(obj.name, u'source-4')
+
+        # Ensure source 4 is created, and everything else is as expected
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'url': '/nullableforeignkeysource/1/', 'name': u'source-1', 'target': '/foreignkeytarget/1/'},
+            {'url': '/nullableforeignkeysource/2/', 'name': u'source-2', 'target': '/foreignkeytarget/1/'},
+            {'url': '/nullableforeignkeysource/3/', 'name': u'source-3', 'target': None},
+            {'url': '/nullableforeignkeysource/4/', 'name': u'source-4', 'target': None}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_update_with_valid_null(self):
+        data = {'url': '/nullableforeignkeysource/1/', 'name': u'source-1', 'target': None}
+        instance = NullableForeignKeySource.objects.get(pk=1)
+        serializer = NullableForeignKeySourceSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        self.assertEquals(serializer.data, data)
+        serializer.save()
+
+        # Ensure source 1 is updated, and everything else is as expected
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'url': '/nullableforeignkeysource/1/', 'name': u'source-1', 'target': None},
+            {'url': '/nullableforeignkeysource/2/', 'name': u'source-2', 'target': '/foreignkeytarget/1/'},
+            {'url': '/nullableforeignkeysource/3/', 'name': u'source-3', 'target': None},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_update_with_valid_emptystring(self):
+        """
+        The emptystring should be interpreted as null in the context
+        of relationships.
+        """
+        data = {'url': '/nullableforeignkeysource/1/', 'name': u'source-1', 'target': ''}
+        expected_data = {'url': '/nullableforeignkeysource/1/', 'name': u'source-1', 'target': None}
+        instance = NullableForeignKeySource.objects.get(pk=1)
+        serializer = NullableForeignKeySourceSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        self.assertEquals(serializer.data, expected_data)
+        serializer.save()
+
+        # Ensure source 1 is updated, and everything else is as expected
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'url': '/nullableforeignkeysource/1/', 'name': u'source-1', 'target': None},
+            {'url': '/nullableforeignkeysource/2/', 'name': u'source-2', 'target': '/foreignkeytarget/1/'},
+            {'url': '/nullableforeignkeysource/3/', 'name': u'source-3', 'target': None},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    # reverse foreign keys MUST be read_only
+    # In the general case they do not provide .remove() or .clear()
+    # and cannot be arbitrarily set.
+
+    # def test_reverse_foreign_key_update(self):
+    #     data = {'id': 1, 'name': u'target-1', 'sources': [1]}
+    #     instance = ForeignKeyTarget.objects.get(pk=1)
+    #     serializer = ForeignKeyTargetSerializer(instance, data=data)
+    #     self.assertTrue(serializer.is_valid())
+    #     self.assertEquals(serializer.data, data)
+    #     serializer.save()
+
+    #     # Ensure target 1 is updated, and everything else is as expected
+    #     queryset = ForeignKeyTarget.objects.all()
+    #     serializer = ForeignKeyTargetSerializer(queryset)
+    #     expected = [
+    #         {'id': 1, 'name': u'target-1', 'sources': [1]},
+    #         {'id': 2, 'name': u'target-2', 'sources': []},
+    #     ]
+    #     self.assertEquals(serializer.data, expected)
diff --git a/rest_framework/tests/relations_nested.py b/rest_framework/tests/relations_nested.py
new file mode 100644
index 00000000..5710c1ef
--- /dev/null
+++ b/rest_framework/tests/relations_nested.py
@@ -0,0 +1,84 @@
+from django.db import models
+from django.test import TestCase
+from rest_framework import serializers
+from rest_framework.tests.models import ForeignKeyTarget, ForeignKeySource, NullableForeignKeySource
+
+
+class ForeignKeySourceSerializer(serializers.ModelSerializer):
+    class Meta:
+        depth = 1
+        model = ForeignKeySource
+
+
+class FlatForeignKeySourceSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ForeignKeySource
+
+
+class ForeignKeyTargetSerializer(serializers.ModelSerializer):
+    sources = FlatForeignKeySourceSerializer()
+
+    class Meta:
+        model = ForeignKeyTarget
+
+
+class NullableForeignKeySourceSerializer(serializers.ModelSerializer):
+    class Meta:
+        depth = 1
+        model = NullableForeignKeySource
+
+
+class ReverseForeignKeyTests(TestCase):
+    def setUp(self):
+        target = ForeignKeyTarget(name='target-1')
+        target.save()
+        new_target = ForeignKeyTarget(name='target-2')
+        new_target.save()
+        for idx in range(1, 4):
+            source = ForeignKeySource(name='source-%d' % idx, target=target)
+            source.save()
+
+    def test_foreign_key_retrieve(self):
+        queryset = ForeignKeySource.objects.all()
+        serializer = ForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': {'id': 1, 'name': u'target-1'}},
+            {'id': 2, 'name': u'source-2', 'target': {'id': 1, 'name': u'target-1'}},
+            {'id': 3, 'name': u'source-3', 'target': {'id': 1, 'name': u'target-1'}},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_foreign_key_retrieve(self):
+        queryset = ForeignKeyTarget.objects.all()
+        serializer = ForeignKeyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'target-1', 'sources': [
+                {'id': 1, 'name': u'source-1', 'target': 1},
+                {'id': 2, 'name': u'source-2', 'target': 1},
+                {'id': 3, 'name': u'source-3', 'target': 1},
+            ]},
+            {'id': 2, 'name': u'target-2', 'sources': [
+            ]}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+
+class NestedNullableForeignKeyTests(TestCase):
+    def setUp(self):
+        target = ForeignKeyTarget(name='target-1')
+        target.save()
+        for idx in range(1, 4):
+            if idx == 3:
+                target = None
+            source = NullableForeignKeySource(name='source-%d' % idx, target=target)
+            source.save()
+
+    def test_foreign_key_retrieve_with_null(self):
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': {'id': 1, 'name': u'target-1'}},
+            {'id': 2, 'name': u'source-2', 'target': {'id': 1, 'name': u'target-1'}},
+            {'id': 3, 'name': u'source-3', 'target': None},
+        ]
+        self.assertEquals(serializer.data, expected)
diff --git a/rest_framework/tests/relations_pk.py b/rest_framework/tests/relations_pk.py
new file mode 100644
index 00000000..af6da2c0
--- /dev/null
+++ b/rest_framework/tests/relations_pk.py
@@ -0,0 +1,385 @@
+from django.db import models
+from django.test import TestCase
+from rest_framework import serializers
+from rest_framework.tests.models import ManyToManyTarget, ManyToManySource, ForeignKeyTarget, ForeignKeySource, NullableForeignKeySource
+
+
+class ManyToManyTargetSerializer(serializers.ModelSerializer):
+    sources = serializers.ManyPrimaryKeyRelatedField()
+
+    class Meta:
+        model = ManyToManyTarget
+
+
+class ManyToManySourceSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ManyToManySource
+
+
+class ForeignKeyTargetSerializer(serializers.ModelSerializer):
+    sources = serializers.ManyPrimaryKeyRelatedField()
+
+    class Meta:
+        model = ForeignKeyTarget
+
+
+class ForeignKeySourceSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ForeignKeySource
+
+
+class NullableForeignKeySourceSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = NullableForeignKeySource
+
+
+# TODO: Add test that .data cannot be accessed prior to .is_valid
+
+class PKManyToManyTests(TestCase):
+    def setUp(self):
+        for idx in range(1, 4):
+            target = ManyToManyTarget(name='target-%d' % idx)
+            target.save()
+            source = ManyToManySource(name='source-%d' % idx)
+            source.save()
+            for target in ManyToManyTarget.objects.all():
+                source.targets.add(target)
+
+    def test_many_to_many_retrieve(self):
+        queryset = ManyToManySource.objects.all()
+        serializer = ManyToManySourceSerializer(queryset)
+        expected = [
+                {'id': 1, 'name': u'source-1', 'targets': [1]},
+                {'id': 2, 'name': u'source-2', 'targets': [1, 2]},
+                {'id': 3, 'name': u'source-3', 'targets': [1, 2, 3]}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_many_to_many_retrieve(self):
+        queryset = ManyToManyTarget.objects.all()
+        serializer = ManyToManyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'target-1', 'sources': [1, 2, 3]},
+            {'id': 2, 'name': u'target-2', 'sources': [2, 3]},
+            {'id': 3, 'name': u'target-3', 'sources': [3]}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_many_to_many_update(self):
+        data = {'id': 1, 'name': u'source-1', 'targets': [1, 2, 3]}
+        instance = ManyToManySource.objects.get(pk=1)
+        serializer = ManyToManySourceSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        serializer.save()
+        self.assertEquals(serializer.data, data)
+
+        # Ensure source 1 is updated, and everything else is as expected
+        queryset = ManyToManySource.objects.all()
+        serializer = ManyToManySourceSerializer(queryset)
+        expected = [
+                {'id': 1, 'name': u'source-1', 'targets': [1, 2, 3]},
+                {'id': 2, 'name': u'source-2', 'targets': [1, 2]},
+                {'id': 3, 'name': u'source-3', 'targets': [1, 2, 3]}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_many_to_many_update(self):
+        data = {'id': 1, 'name': u'target-1', 'sources': [1]}
+        instance = ManyToManyTarget.objects.get(pk=1)
+        serializer = ManyToManyTargetSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        serializer.save()
+        self.assertEquals(serializer.data, data)
+
+        # Ensure target 1 is updated, and everything else is as expected
+        queryset = ManyToManyTarget.objects.all()
+        serializer = ManyToManyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'target-1', 'sources': [1]},
+            {'id': 2, 'name': u'target-2', 'sources': [2, 3]},
+            {'id': 3, 'name': u'target-3', 'sources': [3]}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_many_to_many_create(self):
+        data = {'id': 4, 'name': u'source-4', 'targets': [1, 3]}
+        serializer = ManyToManySourceSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, data)
+        self.assertEqual(obj.name, u'source-4')
+
+        # Ensure source 4 is added, and everything else is as expected
+        queryset = ManyToManySource.objects.all()
+        serializer = ManyToManySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'targets': [1]},
+            {'id': 2, 'name': u'source-2', 'targets': [1, 2]},
+            {'id': 3, 'name': u'source-3', 'targets': [1, 2, 3]},
+            {'id': 4, 'name': u'source-4', 'targets': [1, 3]},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_many_to_many_create(self):
+        data = {'id': 4, 'name': u'target-4', 'sources': [1, 3]}
+        serializer = ManyToManyTargetSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, data)
+        self.assertEqual(obj.name, u'target-4')
+
+        # Ensure target 4 is added, and everything else is as expected
+        queryset = ManyToManyTarget.objects.all()
+        serializer = ManyToManyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'target-1', 'sources': [1, 2, 3]},
+            {'id': 2, 'name': u'target-2', 'sources': [2, 3]},
+            {'id': 3, 'name': u'target-3', 'sources': [3]},
+            {'id': 4, 'name': u'target-4', 'sources': [1, 3]}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+
+class PKForeignKeyTests(TestCase):
+    def setUp(self):
+        target = ForeignKeyTarget(name='target-1')
+        target.save()
+        new_target = ForeignKeyTarget(name='target-2')
+        new_target.save()
+        for idx in range(1, 4):
+            source = ForeignKeySource(name='source-%d' % idx, target=target)
+            source.save()
+
+    def test_foreign_key_retrieve(self):
+        queryset = ForeignKeySource.objects.all()
+        serializer = ForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': 1},
+            {'id': 2, 'name': u'source-2', 'target': 1},
+            {'id': 3, 'name': u'source-3', 'target': 1}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_foreign_key_retrieve(self):
+        queryset = ForeignKeyTarget.objects.all()
+        serializer = ForeignKeyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'target-1', 'sources': [1, 2, 3]},
+            {'id': 2, 'name': u'target-2', 'sources': []},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_update(self):
+        data = {'id': 1, 'name': u'source-1', 'target': 2}
+        instance = ForeignKeySource.objects.get(pk=1)
+        serializer = ForeignKeySourceSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        self.assertEquals(serializer.data, data)
+        serializer.save()
+
+        # Ensure source 1 is updated, and everything else is as expected
+        queryset = ForeignKeySource.objects.all()
+        serializer = ForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': 2},
+            {'id': 2, 'name': u'source-2', 'target': 1},
+            {'id': 3, 'name': u'source-3', 'target': 1}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_foreign_key_update(self):
+        data = {'id': 2, 'name': u'target-2', 'sources': [1, 3]}
+        instance = ForeignKeyTarget.objects.get(pk=2)
+        serializer = ForeignKeyTargetSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        # We shouldn't have saved anything to the db yet since save
+        # hasn't been called.
+        queryset = ForeignKeyTarget.objects.all()
+        new_serializer = ForeignKeyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'target-1', 'sources': [1, 2, 3]},
+            {'id': 2, 'name': u'target-2', 'sources': []},
+        ]        
+        self.assertEquals(new_serializer.data, expected)
+
+        serializer.save()
+        self.assertEquals(serializer.data, data)
+
+        # Ensure target 2 is update, and everything else is as expected
+        queryset = ForeignKeyTarget.objects.all()
+        serializer = ForeignKeyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'target-1', 'sources': [2]},
+            {'id': 2, 'name': u'target-2', 'sources': [1, 3]},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_create(self):
+        data = {'id': 4, 'name': u'source-4', 'target': 2}
+        serializer = ForeignKeySourceSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, data)
+        self.assertEqual(obj.name, u'source-4')
+
+        # Ensure source 4 is added, and everything else is as expected
+        queryset = ForeignKeySource.objects.all()
+        serializer = ForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': 1},
+            {'id': 2, 'name': u'source-2', 'target': 1},
+            {'id': 3, 'name': u'source-3', 'target': 1},
+            {'id': 4, 'name': u'source-4', 'target': 2},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_reverse_foreign_key_create(self):
+        data = {'id': 3, 'name': u'target-3', 'sources': [1, 3]}
+        serializer = ForeignKeyTargetSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, data)
+        self.assertEqual(obj.name, u'target-3')
+
+        # Ensure target 3 is added, and everything else is as expected
+        queryset = ForeignKeyTarget.objects.all()
+        serializer = ForeignKeyTargetSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'target-1', 'sources': [2]},
+            {'id': 2, 'name': u'target-2', 'sources': []},
+            {'id': 3, 'name': u'target-3', 'sources': [1, 3]},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_update_with_invalid_null(self):
+        data = {'id': 1, 'name': u'source-1', 'target': None}
+        instance = ForeignKeySource.objects.get(pk=1)
+        serializer = ForeignKeySourceSerializer(instance, data=data)
+        self.assertFalse(serializer.is_valid())
+        self.assertEquals(serializer.errors, {'target': [u'Value may not be null']})
+
+
+class PKNullableForeignKeyTests(TestCase):
+    def setUp(self):
+        target = ForeignKeyTarget(name='target-1')
+        target.save()
+        for idx in range(1, 4):
+            if idx == 3:
+                target = None
+            source = NullableForeignKeySource(name='source-%d' % idx, target=target)
+            source.save()
+
+    def test_foreign_key_retrieve_with_null(self):
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': 1},
+            {'id': 2, 'name': u'source-2', 'target': 1},
+            {'id': 3, 'name': u'source-3', 'target': None},
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_create_with_valid_null(self):
+        data = {'id': 4, 'name': u'source-4', 'target': None}
+        serializer = NullableForeignKeySourceSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, data)
+        self.assertEqual(obj.name, u'source-4')
+
+        # Ensure source 4 is created, and everything else is as expected
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': 1},
+            {'id': 2, 'name': u'source-2', 'target': 1},
+            {'id': 3, 'name': u'source-3', 'target': None},
+            {'id': 4, 'name': u'source-4', 'target': None}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_create_with_valid_emptystring(self):
+        """
+        The emptystring should be interpreted as null in the context
+        of relationships.
+        """
+        data = {'id': 4, 'name': u'source-4', 'target': ''}
+        expected_data = {'id': 4, 'name': u'source-4', 'target': None}
+        serializer = NullableForeignKeySourceSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        obj = serializer.save()
+        self.assertEquals(serializer.data, expected_data)
+        self.assertEqual(obj.name, u'source-4')
+
+        # Ensure source 4 is created, and everything else is as expected
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': 1},
+            {'id': 2, 'name': u'source-2', 'target': 1},
+            {'id': 3, 'name': u'source-3', 'target': None},
+            {'id': 4, 'name': u'source-4', 'target': None}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_update_with_valid_null(self):
+        data = {'id': 1, 'name': u'source-1', 'target': None}
+        instance = NullableForeignKeySource.objects.get(pk=1)
+        serializer = NullableForeignKeySourceSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        self.assertEquals(serializer.data, data)
+        serializer.save()
+
+        # Ensure source 1 is updated, and everything else is as expected
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': None},
+            {'id': 2, 'name': u'source-2', 'target': 1},
+            {'id': 3, 'name': u'source-3', 'target': None}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    def test_foreign_key_update_with_valid_emptystring(self):
+        """
+        The emptystring should be interpreted as null in the context
+        of relationships.
+        """
+        data = {'id': 1, 'name': u'source-1', 'target': ''}
+        expected_data = {'id': 1, 'name': u'source-1', 'target': None}
+        instance = NullableForeignKeySource.objects.get(pk=1)
+        serializer = NullableForeignKeySourceSerializer(instance, data=data)
+        self.assertTrue(serializer.is_valid())
+        self.assertEquals(serializer.data, expected_data)
+        serializer.save()
+
+        # Ensure source 1 is updated, and everything else is as expected
+        queryset = NullableForeignKeySource.objects.all()
+        serializer = NullableForeignKeySourceSerializer(queryset)
+        expected = [
+            {'id': 1, 'name': u'source-1', 'target': None},
+            {'id': 2, 'name': u'source-2', 'target': 1},
+            {'id': 3, 'name': u'source-3', 'target': None}
+        ]
+        self.assertEquals(serializer.data, expected)
+
+    # reverse foreign keys MUST be read_only
+    # In the general case they do not provide .remove() or .clear()
+    # and cannot be arbitrarily set.
+
+    # def test_reverse_foreign_key_update(self):
+    #     data = {'id': 1, 'name': u'target-1', 'sources': [1]}
+    #     instance = ForeignKeyTarget.objects.get(pk=1)
+    #     serializer = ForeignKeyTargetSerializer(instance, data=data)
+    #     self.assertTrue(serializer.is_valid())
+    #     self.assertEquals(serializer.data, data)
+    #     serializer.save()
+
+    #     # Ensure target 1 is updated, and everything else is as expected
+    #     queryset = ForeignKeyTarget.objects.all()
+    #     serializer = ForeignKeyTargetSerializer(queryset)
+    #     expected = [
+    #         {'id': 1, 'name': u'target-1', 'sources': [1]},
+    #         {'id': 2, 'name': u'target-2', 'sources': []},
+    #     ]
+    #     self.assertEquals(serializer.data, expected)
diff --git a/rest_framework/tests/renderers.py b/rest_framework/tests/renderers.py
index 9be4b114..c1b4e624 100644
--- a/rest_framework/tests/renderers.py
+++ b/rest_framework/tests/renderers.py
@@ -1,13 +1,12 @@
 import pickle
 import re
 
-from django.conf.urls.defaults import patterns, url, include
 from django.core.cache import cache
 from django.test import TestCase
 from django.test.client import RequestFactory
 
 from rest_framework import status, permissions
-from rest_framework.compat import yaml
+from rest_framework.compat import yaml, patterns, url, include
 from rest_framework.response import Response
 from rest_framework.views import APIView
 from rest_framework.renderers import BaseRenderer, JSONRenderer, YAMLRenderer, \
@@ -444,19 +443,19 @@ class CacheRenderTest(TestCase):
             return
         if state == None:
             return
-        if isinstance(state,tuple):
-            if not isinstance(state[0],dict):
-                state=state[1]
+        if isinstance(state, tuple):
+            if not isinstance(state[0], dict):
+                state = state[1]
             else:
-                state=state[0].update(state[1])
+                state = state[0].update(state[1])
         result = {}
         for i in state:
             try:
-                pickle.dumps(state[i],protocol=2)
+                pickle.dumps(state[i], protocol=2)
             except pickle.PicklingError:
                 if not state[i] in seen:
                     seen.append(state[i])
-                    result[i] = cls._get_pickling_errors(state[i],seen)
+                    result[i] = cls._get_pickling_errors(state[i], seen)
         return result
 
     def http_resp(self, http_method, url):
diff --git a/rest_framework/tests/request.py b/rest_framework/tests/request.py
index ff48f3fa..4b032405 100644
--- a/rest_framework/tests/request.py
+++ b/rest_framework/tests/request.py
@@ -1,14 +1,15 @@
 """
 Tests for content parsing, and form-overloaded content parsing.
 """
-from django.conf.urls.defaults import patterns
+import json
 from django.contrib.auth.models import User
+from django.contrib.auth import authenticate, login, logout
+from django.contrib.sessions.middleware import SessionMiddleware
 from django.test import TestCase, Client
-from django.utils import simplejson as json
-
+from django.test.client import RequestFactory
 from rest_framework import status
 from rest_framework.authentication import SessionAuthentication
-from django.test.client import RequestFactory
+from rest_framework.compat import patterns
 from rest_framework.parsers import (
     BaseParser,
     FormParser,
@@ -276,3 +277,37 @@ class TestContentParsingWithAuthentication(TestCase):
 
     #     response = self.csrf_client.post('/', content)
     #     self.assertEqual(status.OK, response.status_code, "POST data is malformed")
+
+
+class TestUserSetter(TestCase):
+
+    def setUp(self):
+        # Pass request object through session middleware so session is
+        # available to login and logout functions
+        self.request = Request(factory.get('/'))
+        SessionMiddleware().process_request(self.request)
+
+        User.objects.create_user('ringo', 'starr@thebeatles.com', 'yellow')
+        self.user = authenticate(username='ringo', password='yellow')
+
+    def test_user_can_be_set(self):
+        self.request.user = self.user
+        self.assertEqual(self.request.user, self.user)
+
+    def test_user_can_login(self):
+        login(self.request, self.user)
+        self.assertEqual(self.request.user, self.user)
+
+    def test_user_can_logout(self):
+        self.request.user = self.user
+        self.assertFalse(self.request.user.is_anonymous())
+        logout(self.request)
+        self.assertTrue(self.request.user.is_anonymous())
+
+
+class TestAuthSetter(TestCase):
+
+    def test_auth_can_be_set(self):
+        request = Request(factory.get('/'))
+        request.auth = 'DUMMY'
+        self.assertEqual(request.auth, 'DUMMY')
diff --git a/rest_framework/tests/response.py b/rest_framework/tests/response.py
index d7b75450..875f4d42 100644
--- a/rest_framework/tests/response.py
+++ b/rest_framework/tests/response.py
@@ -1,8 +1,5 @@
-import unittest
-
-from django.conf.urls.defaults import patterns, url, include
 from django.test import TestCase
-
+from rest_framework.compat import patterns, url, include
 from rest_framework.response import Response
 from rest_framework.views import APIView
 from rest_framework import status
diff --git a/rest_framework/tests/reverse.py b/rest_framework/tests/reverse.py
index fd9a7d64..8c86e1fb 100644
--- a/rest_framework/tests/reverse.py
+++ b/rest_framework/tests/reverse.py
@@ -1,6 +1,6 @@
-from django.conf.urls.defaults import patterns, url
 from django.test import TestCase
 from django.test.client import RequestFactory
+from rest_framework.compat import patterns, url
 from rest_framework.reverse import reverse
 
 factory = RequestFactory()
diff --git a/rest_framework/tests/serializer.py b/rest_framework/tests/serializer.py
index 8d1de429..bd96ba23 100644
--- a/rest_framework/tests/serializer.py
+++ b/rest_framework/tests/serializer.py
@@ -1,9 +1,10 @@
 import datetime
+import pickle
 from django.test import TestCase
 from rest_framework import serializers
-from rest_framework.tests.models import (ActionItem, Anchor, BasicModel,
-    BlankFieldModel, BlogPost, CallableDefaultValueModel, DefaultValueModel,
-    ManyToManyModel, Person, ReadOnlyManyToManyModel)
+from rest_framework.tests.models import (HasPositiveIntegerAsChoice, Album, ActionItem, Anchor, BasicModel,
+    BlankFieldModel, BlogPost, Book, CallableDefaultValueModel, DefaultValueModel,
+    ManyToManyModel, Person, ReadOnlyManyToManyModel, Photo)
 
 
 class SubComment(object):
@@ -40,7 +41,15 @@ class CommentSerializer(serializers.Serializer):
         return instance
 
 
+class BookSerializer(serializers.ModelSerializer):
+    isbn = serializers.RegexField(regex=r'^[0-9]{13}$', error_messages={'invalid': 'isbn has to be exact 13 numbers'})
+
+    class Meta:
+        model = Book
+
+
 class ActionItemSerializer(serializers.ModelSerializer):
+
     class Meta:
         model = ActionItem
 
@@ -51,6 +60,20 @@ class PersonSerializer(serializers.ModelSerializer):
     class Meta:
         model = Person
         fields = ('name', 'age', 'info')
+        read_only_fields = ('age',)
+
+
+class AlbumsSerializer(serializers.ModelSerializer):
+
+    class Meta:
+        model = Album
+        fields = ['title']  # lists are also valid options
+
+
+class PositiveIntegerAsChoiceSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = HasPositiveIntegerAsChoice
+        fields = ['some_integer']
 
 
 class BasicTests(TestCase):
@@ -106,8 +129,21 @@ class BasicTests(TestCase):
         self.assertTrue(serializer.object is expected)
         self.assertEquals(serializer.data['sub_comment'], 'And Merry Christmas!')
 
+    def test_partial_update(self):
+        msg = 'Merry New Year!'
+        partial_data = {'content': msg}
+        serializer = CommentSerializer(self.comment, data=partial_data)
+        self.assertEquals(serializer.is_valid(), False)
+        serializer = CommentSerializer(self.comment, data=partial_data, partial=True)
+        expected = self.comment
+        self.assertEqual(serializer.is_valid(), True)
+        self.assertEquals(serializer.object, expected)
+        self.assertTrue(serializer.object is expected)
+        self.assertEquals(serializer.data['content'], msg)
+
     def test_model_fields_as_expected(self):
-        """ Make sure that the fields returned are the same as defined
+        """
+        Make sure that the fields returned are the same as defined
         in the Meta data
         """
         serializer = PersonSerializer(self.person)
@@ -115,12 +151,25 @@ class BasicTests(TestCase):
                           set(['name', 'age', 'info']))
 
     def test_field_with_dictionary(self):
-        """ Make sure that dictionaries from fields are left intact
+        """
+        Make sure that dictionaries from fields are left intact
         """
         serializer = PersonSerializer(self.person)
         expected = self.person_data
         self.assertEquals(serializer.data['info'], expected)
 
+    def test_read_only_fields(self):
+        """
+        Attempting to update fields set as read_only should have no effect.
+        """
+
+        serializer = PersonSerializer(self.person, data={'name': 'dwight', 'age': 99})
+        self.assertEquals(serializer.is_valid(), True)
+        instance = serializer.save()
+        self.assertEquals(serializer.errors, {})
+        # Assert age is unchanged (35)
+        self.assertEquals(instance.age, self.person_data['age'])
+
 
 class ValidationTests(TestCase):
     def setUp(self):
@@ -134,7 +183,7 @@ class ValidationTests(TestCase):
             'content': 'x' * 1001,
             'created': datetime.datetime(2012, 1, 1)
         }
-        self.actionitem = ActionItem('Some to do item',
+        self.actionitem = ActionItem(title='Some to do item',
         )
 
     def test_create(self):
@@ -192,6 +241,25 @@ class ValidationTests(TestCase):
         self.assertFalse(serializer.is_valid())
         self.assertEquals(serializer.errors, {'content': [u'Test not in value']})
 
+    def test_bad_type_data_is_false(self):
+        """
+        Data of the wrong type is not valid.
+        """
+        data = ['i am', 'a', 'list']
+        serializer = CommentSerializer(self.comment, data=data)
+        self.assertEquals(serializer.is_valid(), False)
+        self.assertEquals(serializer.errors, {'non_field_errors': [u'Invalid data']})
+
+        data = 'and i am a string'
+        serializer = CommentSerializer(self.comment, data=data)
+        self.assertEquals(serializer.is_valid(), False)
+        self.assertEquals(serializer.errors, {'non_field_errors': [u'Invalid data']})
+
+        data = 42
+        serializer = CommentSerializer(self.comment, data=data)
+        self.assertEquals(serializer.is_valid(), False)
+        self.assertEquals(serializer.errors, {'non_field_errors': [u'Invalid data']})
+
     def test_cross_field_validation(self):
 
         class CommentSerializerWithCrossFieldValidator(CommentSerializer):
@@ -224,6 +292,92 @@ class ValidationTests(TestCase):
         self.assertEquals(serializer.is_valid(), True)
         self.assertEquals(serializer.errors, {})
 
+    def test_modelserializer_max_length_exceeded(self):
+        data = {
+            'title': 'x' * 201,
+        }
+        serializer = ActionItemSerializer(data=data)
+        self.assertEquals(serializer.is_valid(), False)
+        self.assertEquals(serializer.errors, {'title': [u'Ensure this value has at most 200 characters (it has 201).']})
+
+    def test_default_modelfield_max_length_exceeded(self):
+        data = {
+            'title': 'Testing "info" field...',
+            'info': 'x' * 13,
+        }
+        serializer = ActionItemSerializer(data=data)
+        self.assertEquals(serializer.is_valid(), False)
+        self.assertEquals(serializer.errors, {'info': [u'Ensure this value has at most 12 characters (it has 13).']})
+
+
+class PositiveIntegerAsChoiceTests(TestCase):
+    def test_positive_integer_in_json_is_correctly_parsed(self):
+        data = {'some_integer':1}
+        serializer = PositiveIntegerAsChoiceSerializer(data=data)
+        self.assertEquals(serializer.is_valid(), True)
+
+class ModelValidationTests(TestCase):
+    def test_validate_unique(self):
+        """
+        Just check if serializers.ModelSerializer handles unique checks via .full_clean()
+        """
+        serializer = AlbumsSerializer(data={'title': 'a'})
+        serializer.is_valid()
+        serializer.save()
+        second_serializer = AlbumsSerializer(data={'title': 'a'})
+        self.assertFalse(second_serializer.is_valid())
+        self.assertEqual(second_serializer.errors,  {'title': [u'Album with this Title already exists.']})
+
+    def test_foreign_key_with_partial(self):
+        """
+        Test ModelSerializer validation with partial=True
+
+        Specifically test foreign key validation.
+        """
+
+        album = Album(title='test')
+        album.save()
+
+        class PhotoSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = Photo
+
+        photo_serializer = PhotoSerializer(data={'description': 'test', 'album': album.pk})
+        self.assertTrue(photo_serializer.is_valid())
+        photo = photo_serializer.save()
+
+        # Updating only the album (foreign key)
+        photo_serializer = PhotoSerializer(instance=photo, data={'album': album.pk}, partial=True)
+        self.assertTrue(photo_serializer.is_valid())
+        self.assertTrue(photo_serializer.save())
+
+        # Updating only the description
+        photo_serializer = PhotoSerializer(instance=photo,
+                                           data={'description': 'new'},
+                                           partial=True)
+
+        self.assertTrue(photo_serializer.is_valid())
+        self.assertTrue(photo_serializer.save())
+
+
+class RegexValidationTest(TestCase):
+    def test_create_failed(self):
+        serializer = BookSerializer(data={'isbn': '1234567890'})
+        self.assertFalse(serializer.is_valid())
+        self.assertEquals(serializer.errors, {'isbn': [u'isbn has to be exact 13 numbers']})
+
+        serializer = BookSerializer(data={'isbn': '12345678901234'})
+        self.assertFalse(serializer.is_valid())
+        self.assertEquals(serializer.errors, {'isbn': [u'isbn has to be exact 13 numbers']})
+
+        serializer = BookSerializer(data={'isbn': 'abcdefghijklm'})
+        self.assertFalse(serializer.is_valid())
+        self.assertEquals(serializer.errors, {'isbn': [u'isbn has to be exact 13 numbers']})
+
+    def test_create_success(self):
+        serializer = BookSerializer(data={'isbn': '1234567890123'})
+        self.assertTrue(serializer.is_valid())
+
 
 class MetadataTests(TestCase):
     def test_empty(self):
@@ -416,6 +570,21 @@ class DefaultValueTests(TestCase):
         self.assertEquals(instance.pk, 1)
         self.assertEquals(instance.text, 'overridden')
 
+    def test_partial_update_default(self):
+        """ Regression test for issue #532 """
+        data = {'text': 'overridden'}
+        serializer = self.serializer_class(data=data, partial=True)
+        self.assertEquals(serializer.is_valid(), True)
+        instance = serializer.save()
+
+        data = {'extra': 'extra_value'}
+        serializer = self.serializer_class(instance=instance, data=data, partial=True)
+        self.assertEquals(serializer.is_valid(), True)
+        instance = serializer.save()
+
+        self.assertEquals(instance.extra, 'extra_value')
+        self.assertEquals(instance.text, 'overridden')
+
 
 class CallableDefaultValueTests(TestCase):
     def setUp(self):
@@ -446,7 +615,10 @@ class CallableDefaultValueTests(TestCase):
 
 
 class ManyRelatedTests(TestCase):
-    def setUp(self):
+    def test_reverse_relations(self):
+        post = BlogPost.objects.create(title="Test blog post")
+        post.blogpostcomment_set.create(text="I hate this blog post")
+        post.blogpostcomment_set.create(text="I love this blog post")
 
         class BlogPostCommentSerializer(serializers.Serializer):
             text = serializers.CharField()
@@ -455,14 +627,7 @@ class ManyRelatedTests(TestCase):
             title = serializers.CharField()
             comments = BlogPostCommentSerializer(source='blogpostcomment_set')
 
-        self.serializer_class = BlogPostSerializer
-
-    def test_reverse_relations(self):
-        post = BlogPost.objects.create(title="Test blog post")
-        post.blogpostcomment_set.create(text="I hate this blog post")
-        post.blogpostcomment_set.create(text="I love this blog post")
-
-        serializer = self.serializer_class(instance=post)
+        serializer = BlogPostSerializer(instance=post)
         expected = {
             'title': 'Test blog post',
             'comments': [
@@ -473,6 +638,100 @@ class ManyRelatedTests(TestCase):
 
         self.assertEqual(serializer.data, expected)
 
+    def test_callable_source(self):
+        post = BlogPost.objects.create(title="Test blog post")
+        post.blogpostcomment_set.create(text="I love this blog post")
+
+        class BlogPostCommentSerializer(serializers.Serializer):
+            text = serializers.CharField()
+
+        class BlogPostSerializer(serializers.Serializer):
+            title = serializers.CharField()
+            first_comment = BlogPostCommentSerializer(source='get_first_comment')
+
+        serializer = BlogPostSerializer(post)
+
+        expected = {
+            'title': 'Test blog post',
+            'first_comment': {'text': 'I love this blog post'}
+        }
+        self.assertEqual(serializer.data, expected)
+
+
+class RelatedTraversalTest(TestCase):
+    def test_nested_traversal(self):
+        user = Person.objects.create(name="django")
+        post = BlogPost.objects.create(title="Test blog post", writer=user)
+        post.blogpostcomment_set.create(text="I love this blog post")
+
+        from rest_framework.tests.models import BlogPostComment
+
+        class PersonSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = Person
+                fields = ("name", "age")
+
+        class BlogPostCommentSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = BlogPostComment
+                fields = ("text", "post_owner")
+
+            text = serializers.CharField()
+            post_owner = PersonSerializer(source='blog_post.writer')
+
+        class BlogPostSerializer(serializers.Serializer):
+            title = serializers.CharField()
+            comments = BlogPostCommentSerializer(source='blogpostcomment_set')
+
+        serializer = BlogPostSerializer(instance=post)
+
+        expected = {
+            'title': u'Test blog post',
+            'comments': [{
+                'text': u'I love this blog post',
+                'post_owner': {
+                    "name": u"django",
+                    "age": None
+                }
+            }]
+        }
+
+        self.assertEqual(serializer.data, expected)
+
+
+class SerializerMethodFieldTests(TestCase):
+    def setUp(self):
+
+        class BoopSerializer(serializers.Serializer):
+            beep = serializers.SerializerMethodField('get_beep')
+            boop = serializers.Field()
+            boop_count = serializers.SerializerMethodField('get_boop_count')
+
+            def get_beep(self, obj):
+                return 'hello!'
+
+            def get_boop_count(self, obj):
+                return len(obj.boop)
+
+        self.serializer_class = BoopSerializer
+
+    def test_serializer_method_field(self):
+
+        class MyModel(object):
+            boop = ['a', 'b', 'c']
+
+        source_data = MyModel()
+
+        serializer = self.serializer_class(source_data)
+
+        expected = {
+            'beep': u'hello!',
+            'boop': [u'a', u'b', u'c'],
+            'boop_count': 3,
+        }
+
+        self.assertEqual(serializer.data, expected)
+
 
 # Test for issue #324
 class BlankFieldTests(TestCase):
@@ -506,6 +765,10 @@ class BlankFieldTests(TestCase):
         serializer = self.model_serializer_class(data=self.data)
         self.assertEquals(serializer.is_valid(), True)
 
+    def test_create_model_null_field(self):
+        serializer = self.model_serializer_class(data={'title': None})
+        self.assertEquals(serializer.is_valid(), True)
+
     def test_create_not_blank_field(self):
         """
         Test to ensure blank data in a field not marked as blank=True
@@ -521,3 +784,120 @@ class BlankFieldTests(TestCase):
         """
         serializer = self.not_blank_model_serializer_class(data=self.data)
         self.assertEquals(serializer.is_valid(), False)
+
+    def test_create_model_null_field(self):
+        serializer = self.model_serializer_class(data={})
+        self.assertEquals(serializer.is_valid(), True)
+
+
+#test for issue #460
+class SerializerPickleTests(TestCase):
+    """
+    Test pickleability of the output of Serializers
+    """
+    def test_pickle_simple_model_serializer_data(self):
+        """
+        Test simple serializer
+        """
+        pickle.dumps(PersonSerializer(Person(name="Methusela", age=969)).data)
+
+    def test_pickle_inner_serializer(self):
+        """
+        Test pickling a serializer whose resulting .data (a SortedDictWithMetadata) will
+        have unpickleable meta data--in order to make sure metadata doesn't get pulled into the pickle.
+        See DictWithMetadata.__getstate__
+        """
+        class InnerPersonSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = Person
+                fields = ('name', 'age')
+        pickle.dumps(InnerPersonSerializer(Person(name="Noah", age=950)).data)
+
+
+class DepthTest(TestCase):
+    def test_implicit_nesting(self):
+        writer = Person.objects.create(name="django", age=1)
+        post = BlogPost.objects.create(title="Test blog post", writer=writer)
+
+        class BlogPostSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = BlogPost
+                depth = 1
+
+        serializer = BlogPostSerializer(instance=post)
+        expected = {'id': 1, 'title': u'Test blog post',
+                    'writer': {'id': 1, 'name': u'django', 'age': 1}}
+
+        self.assertEqual(serializer.data, expected)
+
+    def test_explicit_nesting(self):
+        writer = Person.objects.create(name="django", age=1)
+        post = BlogPost.objects.create(title="Test blog post", writer=writer)
+
+        class PersonSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = Person
+
+        class BlogPostSerializer(serializers.ModelSerializer):
+            writer = PersonSerializer()
+
+            class Meta:
+                model = BlogPost
+
+        serializer = BlogPostSerializer(instance=post)
+        expected = {'id': 1, 'title': u'Test blog post',
+                    'writer': {'id': 1, 'name': u'django', 'age': 1}}
+
+        self.assertEqual(serializer.data, expected)
+
+
+class NestedSerializerContextTests(TestCase):
+
+    def test_nested_serializer_context(self):
+        """
+        Regression for #497
+
+        https://github.com/tomchristie/django-rest-framework/issues/497
+        """
+        class PhotoSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = Photo
+                fields = ("description", "callable")
+
+            callable = serializers.SerializerMethodField('_callable')
+
+            def _callable(self, instance):
+                if not 'context_item' in self.context:
+                    raise RuntimeError("context isn't getting passed into 2nd level nested serializer")
+                return "success"
+
+        class AlbumSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = Album
+                fields = ("photo_set", "callable")
+
+            photo_set = PhotoSerializer(source="photo_set")
+            callable = serializers.SerializerMethodField("_callable")
+
+            def _callable(self, instance):
+                if not 'context_item' in self.context:
+                    raise RuntimeError("context isn't getting passed into 1st level nested serializer")
+                return "success"
+
+        class AlbumCollection(object):
+            albums = None
+
+        class AlbumCollectionSerializer(serializers.Serializer):
+            albums = AlbumSerializer(source="albums")
+
+        album1 = Album.objects.create(title="album 1")
+        album2 = Album.objects.create(title="album 2")
+        Photo.objects.create(description="Bigfoot", album=album1)
+        Photo.objects.create(description="Unicorn", album=album1)
+        Photo.objects.create(description="Yeti", album=album2)
+        Photo.objects.create(description="Sasquatch", album=album2)
+        album_collection = AlbumCollection()
+        album_collection.albums = [album1, album2]
+
+        # This will raise RuntimeError if context doesn't get passed correctly to the nested Serializers
+        AlbumCollectionSerializer(album_collection, context={'context_item': 'album context'}).data
diff --git a/rest_framework/tests/settings.py b/rest_framework/tests/settings.py
new file mode 100644
index 00000000..0293fdc3
--- /dev/null
+++ b/rest_framework/tests/settings.py
@@ -0,0 +1,21 @@
+"""Tests for the settings module"""
+from django.test import TestCase
+
+from rest_framework.settings import APISettings, DEFAULTS, IMPORT_STRINGS
+
+
+class TestSettings(TestCase):
+    """Tests relating to the api settings"""
+
+    def test_non_import_errors(self):
+        """Make sure other errors aren't suppressed."""
+        settings = APISettings({'DEFAULT_MODEL_SERIALIZER_CLASS': 'rest_framework.tests.extras.bad_import.ModelSerializer'}, DEFAULTS, IMPORT_STRINGS)
+        with self.assertRaises(ValueError):
+            settings.DEFAULT_MODEL_SERIALIZER_CLASS
+
+    def test_import_error_message_maintained(self):
+        """Make sure real import errors are captured and raised sensibly."""
+        settings = APISettings({'DEFAULT_MODEL_SERIALIZER_CLASS': 'rest_framework.tests.extras.not_here.ModelSerializer'}, DEFAULTS, IMPORT_STRINGS)
+        with self.assertRaises(ImportError) as cm:
+            settings.DEFAULT_MODEL_SERIALIZER_CLASS
+        self.assertTrue('ImportError' in str(cm.exception))
diff --git a/rest_framework/tests/testcases.py b/rest_framework/tests/testcases.py
index c90224aa..97f492ff 100644
--- a/rest_framework/tests/testcases.py
+++ b/rest_framework/tests/testcases.py
@@ -6,6 +6,7 @@ from django.test import TestCase
 
 NO_SETTING = ('!', None)
 
+
 class TestSettingsManager(object):
     """
     A class which can modify some Django settings temporarily for a
@@ -19,7 +20,7 @@ class TestSettingsManager(object):
         self._original_settings = {}
 
     def set(self, **kwargs):
-        for k,v in kwargs.iteritems():
+        for k, v in kwargs.iteritems():
             self._original_settings.setdefault(k, getattr(settings, k,
                                                           NO_SETTING))
             setattr(settings, k, v)
@@ -31,7 +32,7 @@ class TestSettingsManager(object):
         call_command('syncdb', verbosity=0)
 
     def revert(self):
-        for k,v in self._original_settings.iteritems():
+        for k, v in self._original_settings.iteritems():
             if v == NO_SETTING:
                 delattr(settings, k)
             else:
@@ -57,6 +58,7 @@ class SettingsTestCase(TestCase):
     def tearDown(self):
         self.settings_manager.revert()
 
+
 class TestModelsTestCase(SettingsTestCase):
     def setUp(self, *args, **kwargs):
         installed_apps = tuple(settings.INSTALLED_APPS) + ('rest_framework.tests',)
diff --git a/rest_framework/tests/throttling.py b/rest_framework/tests/throttling.py
index 0b94c25b..4b98b941 100644
--- a/rest_framework/tests/throttling.py
+++ b/rest_framework/tests/throttling.py
@@ -106,7 +106,7 @@ class ThrottlingTests(TestCase):
             if expect is not None:
                 self.assertEquals(response['X-Throttle-Wait-Seconds'], expect)
             else:
-                self.assertFalse('X-Throttle-Wait-Seconds' in response.headers)
+                self.assertFalse('X-Throttle-Wait-Seconds' in response)
 
     def test_seconds_fields(self):
         """
diff --git a/rest_framework/tests/utils.py b/rest_framework/tests/utils.py
new file mode 100644
index 00000000..3906adb9
--- /dev/null
+++ b/rest_framework/tests/utils.py
@@ -0,0 +1,27 @@
+from django.test.client import RequestFactory, FakePayload
+from django.test.client import MULTIPART_CONTENT
+from urlparse import urlparse
+
+
+class RequestFactory(RequestFactory):
+
+    def __init__(self, **defaults):
+        super(RequestFactory, self).__init__(**defaults)
+
+    def patch(self, path, data={}, content_type=MULTIPART_CONTENT,
+            **extra):
+        "Construct a PATCH request."
+
+        patch_data = self._encode_data(data, content_type)
+
+        parsed = urlparse(path)
+        r = {
+            'CONTENT_LENGTH': len(patch_data),
+            'CONTENT_TYPE':   content_type,
+            'PATH_INFO':      self._get_path(parsed),
+            'QUERY_STRING':   parsed[4],
+            'REQUEST_METHOD': 'PATCH',
+            'wsgi.input':     FakePayload(patch_data),
+        }
+        r.update(extra)
+        return self.request(**r)
diff --git a/rest_framework/tests/views.py b/rest_framework/tests/views.py
index 43365e07..7cd82656 100644
--- a/rest_framework/tests/views.py
+++ b/rest_framework/tests/views.py
@@ -18,7 +18,7 @@ class BasicView(APIView):
         return Response({'method': 'POST', 'data': request.DATA})
 
 
-@api_view(['GET', 'POST', 'PUT'])
+@api_view(['GET', 'POST', 'PUT', 'PATCH'])
 def basic_view(request):
     if request.method == 'GET':
         return {'method': 'GET'}
@@ -26,6 +26,8 @@ def basic_view(request):
         return {'method': 'POST', 'data': request.DATA}
     elif request.method == 'PUT':
         return {'method': 'PUT', 'data': request.DATA}
+    elif request.method == 'PATCH':
+        return {'method': 'PATCH', 'data': request.DATA}
 
 
 def sanitise_json_error(error_dict):
diff --git a/rest_framework/urlpatterns.py b/rest_framework/urlpatterns.py
index 316ccd19..143928c9 100644
--- a/rest_framework/urlpatterns.py
+++ b/rest_framework/urlpatterns.py
@@ -1,10 +1,10 @@
-from django.conf.urls.defaults import url
+from rest_framework.compat import url
 from rest_framework.settings import api_settings
 
 
 def format_suffix_patterns(urlpatterns, suffix_required=False, allowed=None):
     """
-    Supplement existing urlpatterns with corrosponding patterns that also
+    Supplement existing urlpatterns with corresponding patterns that also
     include a '.format' suffix.  Retains urlpattern ordering.
 
     urlpatterns:
diff --git a/rest_framework/urls.py b/rest_framework/urls.py
index 1a81101f..fbe4bc07 100644
--- a/rest_framework/urls.py
+++ b/rest_framework/urls.py
@@ -1,7 +1,7 @@
 """
-Login and logout views for the browseable API.
+Login and logout views for the browsable API.
 
-Add these to your root URLconf if you're using the browseable API and
+Add these to your root URLconf if you're using the browsable API and
 your API requires authentication.
 
 The urls must be namespaced as 'rest_framework', and you should make sure
@@ -12,7 +12,7 @@ your authentication settings include `SessionAuthentication`.
         url(r'^auth', include('rest_framework.urls', namespace='rest_framework'))
     )
 """
-from django.conf.urls.defaults import patterns, url
+from rest_framework.compat import patterns, url
 
 
 template_name = {'template_name': 'rest_framework/login.html'}
diff --git a/rest_framework/utils/encoders.py b/rest_framework/utils/encoders.py
index 2d1fb353..c70b24dd 100644
--- a/rest_framework/utils/encoders.py
+++ b/rest_framework/utils/encoders.py
@@ -4,7 +4,7 @@ Helper classes for parsers.
 import datetime
 import decimal
 import types
-from django.utils import simplejson as json
+import json
 from django.utils.datastructures import SortedDict
 from rest_framework.compat import timezone
 from rest_framework.serializers import DictWithMetadata, SortedDictWithMetadata
diff --git a/rest_framework/views.py b/rest_framework/views.py
index c470817a..fdb373da 100644
--- a/rest_framework/views.py
+++ b/rest_framework/views.py
@@ -140,7 +140,7 @@ class APIView(View):
 
     def http_method_not_allowed(self, request, *args, **kwargs):
         """
-        Called if `request.method` does not corrospond to a handler method.
+        Called if `request.method` does not correspond to a handler method.
         """
         raise exceptions.MethodNotAllowed(request.method)