Enable response mimetype validation for non-error responses (#1654)

Addresses a todo left in the code.

We only validate the mimetype if the spec defines which mime-types it
produces, and only for non-error responses.

connexion/decorators/response.py

@@ -64,7 +64,7 @@ def _deduct_content_type(data: t.Any, headers: dict) -> str:
             if not produces:
                 # Produces can be empty/ for empty responses
                 pass
-            if len(produces) == 1:
+            elif len(produces) == 1:
                 content_type = produces[0]
             elif isinstance(data, str) and "text/plain" in produces:
                 content_type = "text/plain"

connexion/middleware/request_validation.py

@@ -53,10 +53,13 @@ def extract_content_type(
         return mime_type, encoding
 
     def validate_mime_type(self, mime_type: str) -> None:
-        """Validate the mime type against the spec.
+        """Validate the mime type against the spec if it defines which mime types are accepted.
 
         :param mime_type: mime type from content type header
         """
+        if not self._operation.consumes:
+            return
+
         # Convert to MediaTypeDict to handle media-ranges
         media_type_dict = MediaTypeDict(
             [(c.lower(), None) for c in self._operation.consumes]

connexion/middleware/response_validation.py

@@ -7,6 +7,7 @@
 from starlette.types import ASGIApp, Receive, Scope, Send
 
 from connexion import utils
+from connexion.datastructures import MediaTypeDict
 from connexion.exceptions import NonConformingResponseHeaders
 from connexion.middleware.abstract import RoutedAPI, RoutedMiddleware
 from connexion.operations import AbstractOperation
@@ -50,11 +51,17 @@ def extract_content_type(
         return mime_type, encoding
 
     def validate_mime_type(self, mime_type: str) -> None:
-        """Validate the mime type against the spec.
+        """Validate the mime type against the spec if it defines which mime types are produced.
 
         :param mime_type: mime type from content type header
         """
-        if mime_type.lower() not in [c.lower() for c in self._operation.produces]:
+        if not self._operation.produces:
+            return
+
+        media_type_dict = MediaTypeDict(
+            [(p.lower(), None) for p in self._operation.produces]
+        )
+        if mime_type.lower() not in media_type_dict:
             raise NonConformingResponseHeaders(
                 detail=f"Invalid Response Content-type ({mime_type}), "
                 f"expected {self._operation.produces}",
@@ -83,11 +90,13 @@ async def wrapped_send(message: t.MutableMapping[str, t.Any]) -> None:
             nonlocal send
 
             if message["type"] == "http.response.start":
-                status = str(message["status"])
                 headers = message["headers"]
+
                 mime_type, encoding = self.extract_content_type(headers)
-                # TODO: Add produces to all tests and fix response content types
-                # self.validate_mime_type(mime_type)
+                if message["status"] < 400:
+                    self.validate_mime_type(mime_type)
+
+                status = str(message["status"])
                 response_definition = self._operation.response_definition(
                     status, mime_type
                 )

connexion/operations/openapi.py

@@ -94,7 +94,7 @@ def __init__(
         response_content_types = []
         for _, defn in self._responses.items():
             response_content_types += defn.get("content", {}).keys()
-        self._produces = response_content_types or ["application/json"]
+        self._produces = response_content_types
         self._consumes = None
 
         logger.debug("consumes: %s" % self.consumes)
@@ -128,7 +128,7 @@ def parameters(self):
     def consumes(self):
         if self._consumes is None:
             request_content = self.request_body.get("content", {})
-            self._consumes = list(request_content.keys()) or ["application/json"]
+            self._consumes = list(request_content.keys())
         return self._consumes
 
     @property

tests/api/test_responses.py

@@ -433,7 +433,7 @@ def test_get_bad_default_response(simple_app):
 def test_streaming_response(simple_app):
     app_client = simple_app.test_client()
     resp = app_client.get("/v1.0/get_streaming_response")
-    assert resp.status_code == 200
+    assert resp.status_code == 200, resp.text
 
 
 def test_oneof(simple_openapi_app):

tests/fixtures/simple/openapi.yaml

@@ -1269,7 +1269,7 @@ paths:
         '200':
           description: OK
           content:
-            application/octet-stream:
+            text/x-python:
               schema:
                 type: string
                 format: binary