implement DjangoFilterBackend.get_schema_operation_parameters

example/tests/unit/test_openapi.py

@@ -0,0 +1,57 @@
+from rest_framework import filters as drf_filters
+
+from rest_framework_json_api import filters as dja_filters
+from rest_framework_json_api.django_filters import backends
+
+from example.views import EntryViewSet
+
+
+class DummyEntryViewSet(EntryViewSet):
+    filter_backends = (dja_filters.QueryParameterValidationFilter, dja_filters.OrderingFilter,
+                       backends.DjangoFilterBackend, drf_filters.SearchFilter)
+    filterset_fields = {
+        'id': ('exact',),
+        'headline': ('exact',),
+    }
+
+
+def test_filters_get_schema_params():
+    """
+    test all my filters for `get_schema_operation_parameters()`
+    """
+    # list of tuples: (filter, expected result)
+    filters = [
+        (dja_filters.QueryParameterValidationFilter, []),
+        (backends.DjangoFilterBackend, [
+            {
+                'name': 'filter[id]', 'required': False, 'in': 'query',
+                'description': 'id', 'schema': {'type': 'string'}
+            },
+            {
+                'name': 'filter[headline]', 'required': False, 'in': 'query',
+                'description': 'headline', 'schema': {'type': 'string'}
+            }
+        ]),
+        (dja_filters.OrderingFilter, [
+            {
+                'name': 'sort', 'required': False, 'in': 'query',
+                'description': 'Which field to use when ordering the results.',
+                'schema': {'type': 'string'}
+            }
+        ]),
+        (drf_filters.SearchFilter, [
+            {
+                'name': 'filter[search]', 'required': False, 'in': 'query',
+                'description': 'A search term.',
+                'schema': {'type': 'string'}
+            }
+        ]),
+    ]
+    view = DummyEntryViewSet()
+
+    for c, expected in filters:
+        f = c()
+        #  get_schema_operation_parameters is only available in DRF >= 3.10
+        if hasattr(f, 'get_schema_operation_parameters'):
+            result = f.get_schema_operation_parameters(view)
+            assert result == expected

rest_framework_json_api/django_filters/backends.py

@@ -1,4 +1,5 @@
 import re
+import warnings
 
 from django_filters import VERSION
 from django_filters.rest_framework import DjangoFilterBackend
@@ -142,3 +143,29 @@ def filter_queryset(self, request, queryset, view):
             return filter_class(kwargs['data'], queryset=queryset, request=request).qs
 
         return queryset
+
+    def get_schema_operation_parameters(self, view):
+        """
+        Return Open API query parameter schema.
+        """
+        try:
+            # queryset = view.get_queryset()
+            queryset = view.queryset
+        except Exception:
+            queryset = None
+            warnings.warn(
+                "{} is not compatible with schema generation".format(view.__class__)
+            )
+
+        filterset_class = self.get_filterset_class(view, queryset)
+        return [] if not filterset_class else [
+            ({
+                'name': 'filter[{}]'.format(field_name.replace('__', '.')),
+                'required': field.extra['required'],
+                'in': 'query',
+                'description': field.label if field.label is not None else field_name,
+                'schema': {
+                    'type': 'string',
+                },
+            }) for field_name, field in filterset_class.base_filters.items()
+        ]