Move AutoSchema serializer instantiation to common method

rest_framework/schemas/openapi.py

@@ -419,23 +419,26 @@ class AutoSchema(ViewInspector):
                     schema['maximum'] = int(digits * '9') + 1
                     schema['minimum'] = -schema['maximum']
 
-    def _get_request_body(self, path, method):
+    def _get_serializer(self, method, path):
         view = self.view
 
-        if method not in ('PUT', 'PATCH', 'POST'):
-            return {}
-
         if not hasattr(view, 'get_serializer'):
-            return {}
+            return None
 
         try:
-            serializer = view.get_serializer()
+            return view.get_serializer()
         except exceptions.APIException:
-            serializer = None
             warnings.warn('{}.get_serializer() raised an exception during '
                           'schema generation. Serializer fields will not be '
                           'generated for {} {}.'
                           .format(view.__class__.__name__, method, path))
+            return None
+
+    def _get_request_body(self, path, method):
+        if method not in ('PUT', 'PATCH', 'POST'):
+            return {}
+
+        serializer = self._get_serializer(path, method)
 
         if not isinstance(serializer, serializers.Serializer):
             return {}
@@ -459,16 +462,7 @@ class AutoSchema(ViewInspector):
     def _get_responses(self, path, method):
         # TODO: Handle multiple codes.
         content = {}
-        view = self.view
-        if hasattr(view, 'get_serializer'):
-            try:
-                serializer = view.get_serializer()
-            except exceptions.APIException:
-                serializer = None
-                warnings.warn('{}.get_serializer() raised an exception during '
-                              'schema generation. Serializer fields will not be '
-                              'generated for {} {}.'
-                              .format(view.__class__.__name__, method, path))
+        serializer = self._get_serializer(path, method)
 
         if isinstance(serializer, serializers.Serializer):
             content = self._map_serializer(serializer)