Merge pull request #280 from tomchristie/hyperlinked-relationships

Hyperlinked relationships

1 files changed, 99 insertions, 9 deletions

diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index 32f2d122..b9ac3776 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -4,9 +4,9 @@ import inspect
 import warnings
 
 from django.core import validators
-from django.core.exceptions import ValidationError
+from django.core.exceptions import ObjectDoesNotExist, ValidationError
+from django.core.urlresolvers import resolve
 from django.conf import settings
-from django.db import DEFAULT_DB_ALIAS
 from django.utils.encoding import is_protected_type, smart_unicode
 from django.utils.translation import ugettext_lazy as _
 from rest_framework.reverse import reverse
@@ -27,6 +27,7 @@ def is_simple_callable(obj):
 class Field(object):
     creation_counter = 0
     empty = ''
+    type_name = None
 
     def __init__(self, source=None):
         self.parent = None
@@ -82,6 +83,10 @@ class Field(object):
 
         if is_protected_type(value):
             return value
+
+        all_callable = getattr(value, 'all', None)
+        if is_simple_callable(all_callable):
+            return [self.to_native(item) for item in value.all()]
         elif hasattr(value, '__iter__') and not isinstance(value, (dict, basestring)):
             return [self.to_native(item) for item in value]
         return smart_unicode(value)
@@ -90,7 +95,7 @@ class Field(object):
         """
         Returns a dictionary of attributes to be used when serializing to xml.
         """
-        if getattr(self, 'type_name', None):
+        if self.type_name:
             return {'type': self.type_name}
         return {}
 
@@ -196,7 +201,7 @@ class ModelField(WritableField):
         value = self.model_field._get_val_from_obj(obj)
         if is_protected_type(value):
             return value
-        return self.model_field.value_to_string(self.obj)
+        return self.model_field.value_to_string(obj)
 
     def attributes(self):
         return {
@@ -223,9 +228,9 @@ class RelatedField(WritableField):
         into[(self.source or field_name) + '_id'] = self.from_native(value)
 
 
-class ManyRelatedField(RelatedField):
+class ManyRelatedMixin(object):
     """
-    Base class for related model managers.
+    Mixin to convert a related field to a many related field.
     """
     def field_to_native(self, obj, field_name):
         value = getattr(obj, self.source or field_name)
@@ -233,8 +238,10 @@ class ManyRelatedField(RelatedField):
 
     def field_from_native(self, data, field_name, into):
         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 == ['']:
@@ -242,6 +249,15 @@ class ManyRelatedField(RelatedField):
         into[field_name] = [self.from_native(item) for item in value]
 
 
+class ManyRelatedField(ManyRelatedMixin, RelatedField):
+    """
+    Base class for related model managers.
+    """
+    pass
+
+
+### PrimaryKey relationships
+
 class PrimaryKeyRelatedField(RelatedField):
     """
     Serializes a related field or related object to a pk value.
@@ -281,13 +297,87 @@ class ManyPrimaryKeyRelatedField(ManyRelatedField):
         return [self.to_native(item.pk) for item in queryset.all()]
 
 
+### Hyperlinked relationships
+
+class HyperlinkedRelatedField(RelatedField):
+    pk_url_kwarg = 'pk'
+    slug_url_kwarg = 'slug'
+    slug_field = 'slug'
+
+    def __init__(self, *args, **kwargs):
+        try:
+            self.view_name = kwargs.pop('view_name')
+        except:
+            raise ValueError("Hyperlinked field requires 'view_name' kwarg")
+        super(HyperlinkedRelatedField, self).__init__(*args, **kwargs)
+
+    def to_native(self, obj):
+        view_name = self.view_name
+        request = self.context.get('request', None)
+        kwargs = {self.pk_url_kwarg: obj.pk}
+        try:
+            return reverse(view_name, kwargs=kwargs, request=request)
+        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)
+        except:
+            pass
+
+        kwargs = {self.pk_url_kwarg: obj.pk, self.slug_url_kwarg: slug}
+        try:
+            return reverse(self.view_name, kwargs=kwargs, request=request)
+        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
+        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:
+            return 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.pk
+
+
+class ManyHyperlinkedRelatedField(ManyRelatedMixin, HyperlinkedRelatedField):
+    pass
+
+
 class HyperlinkedIdentityField(Field):
     """
     A field that represents the model's identity using a hyperlink.
     """
-    def __init__(self, *args, **kwargs):
-        pass
-
     def field_to_native(self, obj, field_name):
         request = self.context.get('request', None)
         view_name = self.parent.opts.view_name