Connexion: In some cases, the connexion sends an incorrect Content-Type in the response header

[grisov]

Description and actual behaviour

I was faced with a situation where it is necessary for the server to send data of different types for one route.
An example of such an OpenAPI specification:

  responses:
    '200':
      description: Return html content
      content:
        text/html:
          schema:
            type: string
    default:
      description: Unexpected error
      content:
        text/plain:
          schema:
            type: string

But in the response header, I always got Content-Type == application / json.
At the same time, it was not possible to change the Content-Type even passing the necessary header as the third argument in the controller.
I demonstrated this situation in the Pull Request #834.

Additional info:

The following lines are present in the source code of the Connexion.
File: "connexion/operations/abstract.py"

def get_mimetype(self):
    if all_json(self.produces):
        try:
            return self.produces[0]
        except IndexError:
            return DEFAULT_MIMETYPE
    elif len(self.produces) == 1:
        return self.produces[0]
    else:
        return DEFAULT_MIMETYPE

In our case:
self.produces == ['text/html', 'text/plain']
and the last branch is triggered in the above quoted code.

• python --version 3.7.0
• pip show connexion | grep "^Version\:"
  2018.0.dev1

[rmanibus]

I faced a similar issue with the following specification:

      responses:
        200:
          description: 'Return Notice'
          content:
            application/pdf:
              schema:
                type: string
                format: binary
        404:
          description: Notice does not exist
          content:
            application/json:
              schema:
                type: string

when application/json is set as a content type for the 404, connexion try to serialize the response and asume content type is json even if a 200 is returned.

return request.content, 200
return request.content, 200, {'Content-Type': 'application/pdf'}

TypeError: Object of type bytes is not JSON serializable

If the 404 content is not set, It is possible to return the pdf but when a 404 is returned the content type is still pdf.

as a workaround, I was able to manually craft the response:

return ConnexionResponse(body={'error':'Not found'} ,status_code=404, content_type='application/json')
# or
return ConnexionResponse(body=request.content ,status_code=200, content_type='application/pdf')

[manoadamro]

did anyone ever manage to return some html?
js and css work ok, just not text types