Port get_schema_fields from DRF

django_filters/compat.py

@@ -1,4 +1,6 @@
 
+from __future__ import absolute_import
+
 import django
 from django.conf import settings
 
@@ -12,6 +14,13 @@
 is_crispy = 'crispy_forms' in settings.INSTALLED_APPS and crispy_forms
 
 
+# coreapi only compatible with DRF 3.4+
+try:
+    from rest_framework.compat import coreapi
+except ImportError:
+    coreapi = None
+
+
 def remote_field(field):
     """
     https://docs.djangoproject.com/en/1.9/releases/1.9/#field-rel-changes

django_filters/rest_framework/backends.py

@@ -89,3 +89,15 @@ def to_html(self, request, queryset, view):
         return template_render(template, context={
             'filter': filter_instance
         })
+
+    def get_schema_fields(self, view):
+        # This is not compatible with widgets where the query param differs from the
+        # filter's attribute name. Notably, this includes `MultiWidget`, where query
+        # params will be of the format `<name>_0`, `<name>_1`, etc...
+        assert compat.coreapi is not None, 'coreapi must be installed to use `get_schema_fields()`'
+        filter_class = self.get_filter_class(view, view.get_queryset())
+
+        return [] if not filter_class else [
+            compat.coreapi.Field(name=field_name, required=False, location='query')
+            for field_name in filter_class().filters.keys()
+        ]

requirements/test-ci.txt

@@ -1,3 +1,5 @@
+coreapi
+
 coverage
 mock
 pytz

requirements/test.txt

@@ -1,3 +1,3 @@
--r travis-ci.txt
+-r test-ci.txt
 django
 djangorestframework

tests/rest_framework/test_backends.py

@@ -2,6 +2,7 @@
 
 import datetime
 from decimal import Decimal
+from unittest import skipIf
 
 from django.conf.urls import url
 from django.test import TestCase
@@ -17,7 +18,7 @@
 from rest_framework import generics, serializers, status
 from rest_framework.test import APIRequestFactory
 
-from django_filters import filters
+from django_filters import compat, filters
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from django_filters.rest_framework import backends
 
@@ -121,6 +122,35 @@ def get_queryset(self):
 ]
 
 
+@skipIf(compat.coreapi is None, 'coreapi must be installed')
+class GetSchemaFieldsTests(TestCase):
+    def test_fields_with_filter_fields_list(self):
+        backend = DjangoFilterBackend()
+        fields = backend.get_schema_fields(FilterFieldsRootView())
+        fields = [f.name for f in fields]
+
+        self.assertEqual(fields, ['decimal', 'date'])
+
+    def test_fields_with_filter_fields_dict(self):
+        class DictFilterFieldsRootView(FilterFieldsRootView):
+            filter_fields = {
+                'decimal': ['exact', 'lt', 'gt'],
+            }
+
+        backend = DjangoFilterBackend()
+        fields = backend.get_schema_fields(DictFilterFieldsRootView())
+        fields = [f.name for f in fields]
+
+        self.assertEqual(fields, ['decimal', 'decimal__lt', 'decimal__gt'])
+
+    def test_fields_with_filter_class(self):
+        backend = DjangoFilterBackend()
+        fields = backend.get_schema_fields(FilterClassRootView())
+        fields = [f.name for f in fields]
+
+        self.assertEqual(fields, ['text', 'decimal', 'date'])
+
+
 class CommonFilteringTestCase(TestCase):
     def _serialize_object(self, obj):
         return {'id': obj.id, 'text': obj.text, 'decimal': str(obj.decimal), 'date': obj.date.isoformat()}