Allow body on HTTP DELETE view methods (#122)

* Allow body in delete requests
* Do not add request body to DELETE by default
* Check manual form parameters against body_methods
* Add tests
* Add changelog

Closes #118

docs/changelog.rst

@@ -12,6 +12,7 @@ Changelog
 - **IMPROVED:** updated ``swagger-ui`` to version 3.14.2
 - **IMPROVED:** updated ``ReDoc`` to version 2.0.0-alpha.20
 - **FIXED:** ignore ``None`` return from ``get_operation`` to avoid empty ``Path`` objects in output
+- **FIXED:** request body is now allowed on ``DELETE`` endpoints (:issue:`118`)
 
 *********
 **1.7.3**

src/drf_yasg/inspectors/base.py

@@ -276,7 +276,10 @@ class SerializerInspector(FieldInspector):
 
 
 class ViewInspector(BaseInspector):
-    body_methods = ('PUT', 'PATCH', 'POST')  #: methods that are allowed to have a request body
+    body_methods = ('PUT', 'PATCH', 'POST', 'DELETE')  #: methods that are allowed to have a request body
+
+    #: methods that are assumed to require a request body determined by the view's ``serializer_class``
+    implicit_body_methods = ('PUT', 'PATCH', 'POST')
 
     # real values set in __init__ to prevent import errors
     field_inspectors = []  #:

src/drf_yasg/inspectors/view.py

@@ -101,7 +101,7 @@ class SwaggerAutoSchema(ViewInspector):
             if isinstance(body_override, openapi.Schema.OR_REF):
                 return body_override
             return force_serializer_instance(body_override)
-        elif self.method in self.body_methods:
+        elif self.method in self.implicit_body_methods:
             return self.get_view_serializer()
 
         return None
@@ -144,8 +144,11 @@ class SwaggerAutoSchema(ViewInspector):
             raise SwaggerGenerationError("specify the body parameter as a Schema or Serializer in request_body")
         if any(param.in_ == openapi.IN_FORM for param in manual_parameters):  # pragma: no cover
             if any(param.in_ == openapi.IN_BODY for param in parameters.values()):
-                raise SwaggerGenerationError("cannot add form parameters when the request has a request schema; "
+                raise SwaggerGenerationError("cannot add form parameters when the request has a request body; "
                                              "did you forget to set an appropriate parser class on the view?")
+            if self.method not in self.body_methods:
+                raise SwaggerGenerationError("form parameters can only be applied to (" + ','.join(self.body_methods) +
+                                             ") HTTP methods")
 
         parameters.update(param_list_to_odict(manual_parameters))
         return list(parameters.values())

testproj/snippets/views.py

@@ -33,6 +33,21 @@ class SnippetList(generics.ListCreateAPIView):
         """post method docstring"""
         return super(SnippetList, self).post(request, *args, **kwargs)
 
+    @swagger_auto_schema(
+        operation_id='snippets_delete_bulk',
+        request_body=openapi.Schema(
+            type=openapi.TYPE_OBJECT,
+            properties={
+                'body': openapi.Schema(
+                    type=openapi.TYPE_STRING,
+                    description='this should not crash (request body on DELETE method)'
+                )
+            }
+        ),
+    )
+    def delete(self, *args, **kwargs):
+        pass
+
 
 class SnippetDetail(generics.RetrieveUpdateDestroyAPIView):
     """
@@ -56,18 +71,26 @@ class SnippetDetail(generics.RetrieveUpdateDestroyAPIView):
         """patch method docstring"""
         return super(SnippetDetail, self).patch(request, *args, **kwargs)
 
-    @swagger_auto_schema(manual_parameters=[
+    @swagger_auto_schema(
+        manual_parameters=[
             openapi.Parameter(
                 name='id', in_=openapi.IN_PATH,
                 type=openapi.TYPE_INTEGER,
                 description="path parameter override",
                 required=True
             ),
-    ], responses={
+            openapi.Parameter(
+                name='delete_form_param', in_=openapi.IN_FORM,
+                type=openapi.TYPE_INTEGER,
+                description="this should not crash (form parameter on DELETE method)"
+            ),
+        ],
+        responses={
             status.HTTP_204_NO_CONTENT: openapi.Response(
-            description="This should not crash"
+                description="this should not crash (response object with no schema)"
+            )
+        }
     )
-    })
     def delete(self, request, *args, **kwargs):
         """delete method docstring"""
         return super(SnippetDetail, self).patch(request, *args, **kwargs)

tests/reference.yaml

@@ -388,6 +388,24 @@ paths:
             $ref: '#/definitions/Snippet'
       tags:
         - snippets
+    delete:
+      operationId: snippetsDeleteBulk
+      description: SnippetList classdoc
+      parameters:
+        - name: data
+          in: body
+          required: true
+          schema:
+            type: object
+            properties:
+              body:
+                description: this should not crash (request body on DELETE method)
+                type: string
+      responses:
+        '204':
+          description: ''
+      tags:
+        - snippets
     parameters: []
   /snippets/{id}/:
     get:
@@ -442,9 +460,13 @@ paths:
           description: path parameter override
           required: true
           type: integer
+        - name: delete_form_param
+          in: formData
+          description: this should not crash (form parameter on DELETE method)
+          type: integer
       responses:
         '204':
-          description: This should not crash
+          description: this should not crash (response object with no schema)
       tags:
         - snippets
     parameters: