Use Quality values in "Accept" request header

Created by: ackintosh

Description

In the case below:

openapi: 3.0.0

servers:
- url: http://localhost/myapi

info:
  version: "1.0"
  title: My API

security:
- basicAuth: []

paths:

  /download:
    get:
      operationId: download
      responses:
        200:
          description: OK
          content:
            application/octet-stream:
              schema:
                type: string
                format: binary
        500:
          description: Error
          content:
            application/json:
              schema:
                type: string

the generated api client (e.g. python client) selects application/json as Accept header. but the API server accepts application/octet-stream. (the API server returns application/json only in case of 500 error.) So the request from the API client is always result as 406 Not accepted.

openapi-generator version

latest master

Related issues/PRs

https://github.com/OpenAPITools/openapi-generator/issues/440

Suggest a fix/enhancement

Use Quality values in "Accept" request header instead of removing all media types except application/json.

Accept: application/json,application/octet-stream;q=0.9

list all media types defined in a spec
application/json is set always default value ( 1 )
other media types is set q=0.9

This suggestion keeps the priority that api client needs and avoid the error described above.