Pagination support

7 files changed, 151 insertions, 14 deletions

diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index eab90617..74675ee9 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -139,7 +139,13 @@ class Field(object):
         if hasattr(self, 'model_field'):
             return self.to_native(self.model_field._get_val_from_obj(obj))
 
-        return self.to_native(getattr(obj, self.source or field_name))
+        if self.source:
+            value = obj
+            for component in self.source.split('.'):
+                value = getattr(value, component)
+        else:
+            value = getattr(obj, field_name)
+        return self.to_native(value)
 
     def to_native(self, value):
         """
@@ -175,7 +181,7 @@ class RelatedField(Field):
     """
 
     def field_to_native(self, obj, field_name):
-        obj = getattr(obj, field_name)
+        obj = getattr(obj, self.source or field_name)
         if obj.__class__.__name__ in ('RelatedManager', 'ManyRelatedManager'):
             return [self.to_native(item) for item in obj.all()]
         return self.to_native(obj)
@@ -215,10 +221,10 @@ class PrimaryKeyRelatedField(RelatedField):
 
     def field_to_native(self, obj, field_name):
         try:
-            obj = obj.serializable_value(field_name)
+            obj = obj.serializable_value(self.source or field_name)
         except AttributeError:
             field = obj._meta.get_field_by_name(field_name)[0]
-            obj = getattr(obj, field_name)
+            obj = getattr(obj, self.source or field_name)
             if obj.__class__.__name__ == 'RelatedManager':
                 return [self.to_native(item.pk) for item in obj.all()]
             elif isinstance(field, RelatedObject):
diff --git a/rest_framework/generics.py b/rest_framework/generics.py
index 4240e33e..1e547b32 100644
--- a/rest_framework/generics.py
+++ b/rest_framework/generics.py
@@ -2,7 +2,8 @@
 Generic views that provide commmonly needed behaviour.
 """
 
-from rest_framework import views, mixins, serializers
+from rest_framework import views, mixins
+from rest_framework.settings import api_settings
 from django.views.generic.detail import SingleObjectMixin
 from django.views.generic.list import MultipleObjectMixin
 
@@ -14,23 +15,37 @@ class BaseView(views.APIView):
     Base class for all other generic views.
     """
     serializer_class = None
+    model_serializer_class = api_settings.MODEL_SERIALIZER
+    pagination_serializer_class = api_settings.PAGINATION_SERIALIZER
+    paginate_by = api_settings.PAGINATE_BY
 
-    def get_serializer(self, data=None, files=None, instance=None):
+    def get_serializer_context(self):
+        return {
+            'request': self.request,
+            'format': self.kwargs.get('format', None)
+        }
+
+    def get_serializer(self, data=None, files=None, instance=None, kwargs=None):
         # TODO: add support for files
         # TODO: add support for seperate serializer/deserializer
         serializer_class = self.serializer_class
+        kwargs = kwargs or {}
 
         if serializer_class is None:
-            class DefaultSerializer(serializers.ModelSerializer):
+            class DefaultSerializer(self.model_serializer_class):
                 class Meta:
                     model = self.model
             serializer_class = DefaultSerializer
 
-        context = {
-            'request': self.request,
-            'format': self.kwargs.get('format', None)
-        }
-        return serializer_class(data, instance=instance, context=context)
+        context = self.get_serializer_context()
+        return serializer_class(data, instance=instance, context=context, **kwargs)
+
+    def get_pagination_serializer(self, page=None):
+        serializer_class = self.pagination_serializer_class
+        context = self.get_serializer_context()
+        ret = serializer_class(instance=page, context=context)
+        ret.fields['results'] = self.get_serializer(kwargs={'source': 'object_list'})
+        return ret
 
 
 class MultipleObjectBaseView(MultipleObjectMixin, BaseView):
diff --git a/rest_framework/mixins.py b/rest_framework/mixins.py
index fe12dc8f..167cd89a 100644
--- a/rest_framework/mixins.py
+++ b/rest_framework/mixins.py
@@ -7,6 +7,7 @@ which allows mixin classes to be composed in interesting ways.
 Eg. Use mixins to build a Resource class, and have a Router class
     perform the binding of http methods to actions for us.
 """
+from django.http import Http404
 from rest_framework import status
 from rest_framework.response import Response
 
@@ -30,9 +31,27 @@ class ListModelMixin(object):
     List a queryset.
     Should be mixed in with `MultipleObjectBaseView`.
     """
+    empty_error = u"Empty list and '%(class_name)s.allow_empty' is False."
+
     def list(self, request, *args, **kwargs):
         self.object_list = self.get_queryset()
-        serializer = self.get_serializer(instance=self.object_list)
+
+        # 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)
+
+        # Pagination size is set by the `.paginate_by` attribute,
+        # which may be `None` to disable pagination.
+        page_size = self.get_paginate_by(self.object_list)
+        if page_size:
+            paginator, page, queryset, is_paginated = self.paginate_queryset(self.object_list, page_size)
+            serializer = self.get_pagination_serializer(page)
+        else:
+            serializer = self.get_serializer(instance=self.object_list)
+
         return Response(serializer.data)
 
 
diff --git a/rest_framework/pagination.py b/rest_framework/pagination.py
new file mode 100644
index 00000000..398e6f3d
--- /dev/null
+++ b/rest_framework/pagination.py
@@ -0,0 +1,34 @@
+from rest_framework import serializers
+
+# TODO: Support URLconf kwarg-style paging
+
+
+class NextPageField(serializers.Field):
+    def to_native(self, value):
+        if not value.has_next():
+            return None
+        page = value.next_page_number()
+        request = self.context['request']
+        return request.build_absolute_uri('?page=%d' % page)
+
+
+class PreviousPageField(serializers.Field):
+    def to_native(self, value):
+        if not value.has_previous():
+            return None
+        page = value.previous_page_number()
+        request = self.context['request']
+        return request.build_absolute_uri('?page=%d' % page)
+
+
+class PaginationSerializer(serializers.Serializer):
+    count = serializers.Field(source='paginator.count')
+    next = NextPageField(source='*')
+    previous = PreviousPageField(source='*')
+
+    def to_native(self, obj):
+        """
+        Prevent default behaviour of iterating over elements, and serializing
+        each in turn.
+        """
+        return self.convert_object(obj)
diff --git a/rest_framework/settings.py b/rest_framework/settings.py
index cfc89fe1..8387fd29 100644
--- a/rest_framework/settings.py
+++ b/rest_framework/settings.py
@@ -44,6 +44,10 @@ DEFAULTS = {
         'anon': None,
     },
 
+    'MODEL_SERIALIZER': 'rest_framework.serializers.ModelSerializer',
+    'PAGINATION_SERIALIZER': 'rest_framework.pagination.PaginationSerializer',
+    'PAGINATE_BY': 20,
+
     'UNAUTHENTICATED_USER': 'django.contrib.auth.models.AnonymousUser',
     'UNAUTHENTICATED_TOKEN': None,
 
@@ -65,6 +69,8 @@ IMPORT_STRINGS = (
     'DEFAULT_PERMISSIONS',
     'DEFAULT_THROTTLES',
     'DEFAULT_CONTENT_NEGOTIATION',
+    'MODEL_SERIALIZER',
+    'PAGINATION_SERIALIZER',
     'UNAUTHENTICATED_USER',
     'UNAUTHENTICATED_TOKEN',
 )
diff --git a/rest_framework/templatetags/rest_framework.py b/rest_framework/templatetags/rest_framework.py
index 377fd489..c9b6eb10 100644
--- a/rest_framework/templatetags/rest_framework.py
+++ b/rest_framework/templatetags/rest_framework.py
@@ -1,5 +1,5 @@
 from django import template
-from django.core.urlresolvers import reverse, NoReverseMatch
+from django.core.urlresolvers import reverse
 from django.http import QueryDict
 from django.utils.encoding import force_unicode
 from django.utils.html import escape
diff --git a/rest_framework/tests/pagination.py b/rest_framework/tests/pagination.py
new file mode 100644
index 00000000..4ddfc915
--- /dev/null
+++ b/rest_framework/tests/pagination.py
@@ -0,0 +1,57 @@
+from django.test import TestCase
+from django.test.client import RequestFactory
+from rest_framework import generics, status
+from rest_framework.tests.models import BasicModel
+
+factory = RequestFactory()
+
+
+class RootView(generics.RootAPIView):
+    """
+    Example description for OPTIONS.
+    """
+    model = BasicModel
+    paginate_by = 10
+
+
+class TestPaginatedView(TestCase):
+    def setUp(self):
+        """
+        Create 26 BasicModel intances.
+        """
+        for char in 'abcdefghijklmnopqrstuvwxyz':
+            BasicModel(text=char * 3).save()
+        self.objects = BasicModel.objects
+        self.data = [
+            {'id': obj.id, 'text': obj.text}
+            for obj in self.objects.all()
+        ]
+        self.view = RootView.as_view()
+
+    def test_get_paginated_root_view(self):
+        """
+        GET requests to paginated RootAPIView should return paginated results.
+        """
+        request = factory.get('/')
+        response = self.view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        self.assertEquals(response.data['count'], 26)
+        self.assertEquals(response.data['results'], self.data[:10])
+        self.assertNotEquals(response.data['next'], None)
+        self.assertEquals(response.data['previous'], None)
+
+        request = factory.get(response.data['next'])
+        response = self.view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        self.assertEquals(response.data['count'], 26)
+        self.assertEquals(response.data['results'], self.data[10:20])
+        self.assertNotEquals(response.data['next'], None)
+        self.assertNotEquals(response.data['previous'], None)
+
+        request = factory.get(response.data['next'])
+        response = self.view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        self.assertEquals(response.data['count'], 26)
+        self.assertEquals(response.data['results'], self.data[20:])
+        self.assertEquals(response.data['next'], None)
+        self.assertNotEquals(response.data['previous'], None)