Adds the following features:

- support for post and patch request on polymorphic model endpoints.
- makes polymorphic serializers give child fields instead of its own.

Author: ograycode

example/migrations/0002_auto_20160513_0857.py

@@ -0,0 +1,71 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.6 on 2016-05-13 08:57
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('contenttypes', '0002_remove_content_type_name'),
+        ('example', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Company',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Project',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('topic', models.CharField(max_length=30)),
+            ],
+            options={
+                'abstract': False,
+            },
+        ),
+        migrations.CreateModel(
+            name='ArtProject',
+            fields=[
+                ('project_ptr', models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='example.Project')),
+                ('artist', models.CharField(max_length=30)),
+            ],
+            options={
+                'abstract': False,
+            },
+            bases=('example.project',),
+        ),
+        migrations.CreateModel(
+            name='ResearchProject',
+            fields=[
+                ('project_ptr', models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='example.Project')),
+                ('supervisor', models.CharField(max_length=30)),
+            ],
+            options={
+                'abstract': False,
+            },
+            bases=('example.project',),
+        ),
+        migrations.AddField(
+            model_name='project',
+            name='polymorphic_ctype',
+            field=models.ForeignKey(editable=False, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='polymorphic_example.project_set+', to='contenttypes.ContentType'),
+        ),
+        migrations.AddField(
+            model_name='company',
+            name='current_project',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='companies', to='example.Project'),
+        ),
+        migrations.AddField(
+            model_name='company',
+            name='future_projects',
+            field=models.ManyToManyField(to='example.Project'),
+        ),
+    ]

example/serializers.py

@@ -1,5 +1,7 @@
 from datetime import datetime
-from rest_framework_json_api import serializers, relations
+from django.db.models.query import QuerySet
+from rest_framework.utils.serializer_helpers import BindingDict
+from rest_framework_json_api import serializers, relations, utils
 from example import models
 
 
@@ -43,13 +45,13 @@ def __init__(self, *args, **kwargs):
             source='comment_set', many=True, read_only=True)
     # many related from serializer
     suggested = relations.SerializerMethodResourceRelatedField(
-            source='get_suggested', model=Entry, many=True, read_only=True)
+            source='get_suggested', model=models.Entry, many=True, read_only=True)
     # single related from serializer
     featured = relations.SerializerMethodResourceRelatedField(
-            source='get_featured', model=Entry, read_only=True)
+            source='get_featured', model=models.Entry, read_only=True)
 
     def get_suggested(self, obj):
-        return models.Entry.objects.exclude(pk=obj.pk).first()
+        return models.Entry.objects.exclude(pk=obj.pk)
 
     def get_featured(self, obj):
         return models.Entry.objects.exclude(pk=obj.pk).first()
@@ -107,19 +109,48 @@ class Meta:
 
 class ProjectSerializer(serializers.ModelSerializer):
 
+    polymorphic_serializers = [
+        {'model': models.ArtProject, 'serializer': ArtProjectSerializer},
+        {'model': models.ResearchProject, 'serializer': ResearchProjectSerializer},
+    ]
+
     class Meta:
         model = models.Project
         exclude = ('polymorphic_ctype',)
 
+    def _get_actual_serializer_from_instance(self, instance):
+        for info in self.polymorphic_serializers:
+            if isinstance(instance, info.get('model')):
+                actual_serializer = info.get('serializer')
+                return actual_serializer(instance, context=self.context)
+
+    @property
+    def fields(self):
+        _fields = BindingDict(self)
+        for key, value in self.get_fields().items():
+            _fields[key] = value
+        return _fields
+
+    def get_fields(self):
+        if self.instance is not None:
+            if not isinstance(self.instance, QuerySet):
+                return self._get_actual_serializer_from_instance(self.instance).get_fields()
+            else:
+                raise Exception("Cannot get fields from a polymorphic serializer given a queryset")
+        return super(ProjectSerializer, self).get_fields()
+
     def to_representation(self, instance):
         # Handle polymorphism
-        if isinstance(instance, models.ArtProject):
-            return ArtProjectSerializer(
-                instance, context=self.context).to_representation(instance)
-        elif isinstance(instance, models.ResearchProject):
-            return ResearchProjectSerializer(
-                instance, context=self.context).to_representation(instance)
-        return super(ProjectSerializer, self).to_representation(instance)
+        return self._get_actual_serializer_from_instance(instance).to_representation(instance)
+
+    def to_internal_value(self, data):
+        data_type = data.get('type')
+        for info in self.polymorphic_serializers:
+            actual_serializer = info['serializer']
+            if data_type == utils.get_resource_type_from_serializer(actual_serializer):
+                self.__class__ = actual_serializer
+                return actual_serializer(data, context=self.context).to_internal_value(data)
+        raise Exception("Could not deserialize")
 
 
 class CompanySerializer(serializers.ModelSerializer):

example/tests/integration/test_polymorphism.py

@@ -1,4 +1,6 @@
 import pytest
+import random
+import json
 from django.core.urlresolvers import reverse
 
 from example.tests.utils import load_json
@@ -29,3 +31,41 @@ def test_polymorphism_on_included_relations(single_company, client):
         "researchProjects", "artProjects"]
     assert [x.get('type') for x in content.get('included')] == ['artProjects', 'artProjects', 'researchProjects'], \
         'Detail included types are incorrect'
+    # Ensure that the child fields are present.
+    assert content.get('included')[0].get('attributes').get('artist') is not None
+    assert content.get('included')[1].get('attributes').get('artist') is not None
+    assert content.get('included')[2].get('attributes').get('supervisor') is not None
+
+def test_polymorphism_on_polymorphic_model_detail_patch(single_art_project, client):
+    url = reverse("project-detail", kwargs={'pk': single_art_project.pk})
+    response = client.get(url)
+    content = load_json(response.content)
+    test_topic = 'test-{}'.format(random.randint(0, 999999))
+    test_artist = 'test-{}'.format(random.randint(0, 999999))
+    content['data']['attributes']['topic'] = test_topic
+    content['data']['attributes']['artist'] = test_artist
+    response = client.patch(url, data=json.dumps(content), content_type='application/vnd.api+json')
+    new_content = load_json(response.content)
+    assert new_content["data"]["type"] == "artProjects"
+    assert new_content['data']['attributes']['topic'] == test_topic
+    assert new_content['data']['attributes']['artist'] == test_artist
+
+def test_polymorphism_on_polymorphic_model_list_post(client):
+    test_topic = 'New test topic {}'.format(random.randint(0, 999999))
+    test_artist = 'test-{}'.format(random.randint(0, 999999))
+    url = reverse('project-list')
+    data = {
+        'data': {
+            'type': 'artProjects',
+            'attributes': {
+                'topic': test_topic,
+                'artist': test_artist
+            }
+        }
+    }
+    response = client.post(url, data=json.dumps(data), content_type='application/vnd.api+json')
+    content = load_json(response.content)
+    assert content['data']['id'] is not None
+    assert content["data"]["type"] == "artProjects"
+    assert content['data']['attributes']['topic'] == test_topic
+    assert content['data']['attributes']['artist'] == test_artist

rest_framework_json_api/parsers.py

@@ -1,6 +1,7 @@
 """
 Parsers
 """
+import six
 from rest_framework import parsers
 from rest_framework.exceptions import ParseError
 
@@ -72,7 +73,11 @@ def parse(self, stream, media_type=None, parser_context=None):
 
             # Check for inconsistencies
             resource_name = utils.get_resource_name(parser_context)
-            if data.get('type') != resource_name and request.method in ('PUT', 'POST', 'PATCH'):
+            if isinstance(resource_name, six.string_types):
+                doesnt_match = data.get('type') != resource_name
+            else:
+                doesnt_match = data.get('type') not in resource_name
+            if doesnt_match and request.method in ('PUT', 'POST', 'PATCH'):
                 raise exceptions.Conflict(
                     "The resource object's type ({data_type}) is not the type "
                     "that constitute the collection represented by the endpoint ({resource_type}).".format(
@@ -82,7 +87,7 @@ def parse(self, stream, media_type=None, parser_context=None):
                 )
 
             # Construct the return data
-            parsed_data = {'id': data.get('id')}
+            parsed_data = {'id': data.get('id'), 'type': data.get('type')}
             parsed_data.update(self.parse_attributes(data))
             parsed_data.update(self.parse_relationships(data))
             return parsed_data

rest_framework_json_api/renderers.py

@@ -289,8 +289,6 @@ def extract_included(fields, resource, resource_instance, included_resources):
                 relation_type = utils.get_resource_type_from_serializer(serializer)
                 relation_queryset = list(relation_instance_or_manager.all())
 
-                # Get the serializer fields
-                serializer_fields = utils.get_serializer_fields(serializer)
                 if serializer_data:
                     for position in range(len(serializer_data)):
                         serializer_resource = serializer_data[position]
@@ -299,6 +297,7 @@ def extract_included(fields, resource, resource_instance, included_resources):
                             relation_type or
                             utils.get_resource_type_from_instance(nested_resource_instance)
                         )
+                        serializer_fields = utils.get_serializer_fields(serializer.__class__(nested_resource_instance, context=serializer.context))
                         included_data.append(
                             JSONRenderer.build_json_resource_obj(
                                 serializer_fields, serializer_resource, nested_resource_instance, resource_type

rest_framework_json_api/utils.py

@@ -231,7 +231,9 @@ def get_resource_type_from_manager(manager):
 
 
 def get_resource_type_from_serializer(serializer):
-    if hasattr(serializer.Meta, 'resource_name'):
+    if hasattr(serializer, 'polymorphic_serializers'):
+        return [get_resource_type_from_serializer(s['serializer']) for s in serializer.polymorphic_serializers]
+    elif hasattr(serializer.Meta, 'resource_name'):
         return serializer.Meta.resource_name
     else:
         return get_resource_type_from_model(serializer.Meta.model)