Enabling CORS with openapi-generator

Question

So I'm using openapi-generator to generate a flask server to serve my api.

I am having no trouble generating the server running it and viewing endpoints in my browser. However I get a CORS error when I make a GET request from my React Web App.

I've tried a few things to enable CORS.

I tried adding the header to my endpoint in my .yaml.

/pipelines:
    get:
      summary: 'Returns a list of pipelines.'
      operationId: get_pipelines
      responses:
        '200':
          description: 'A JSON array of pipelines'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Pipeline'
          headers:
            Access-Control-Allow-Origin: '*'
        default:
          description: Unexpected error
          content:
            'application/json':
              schema:
                $ref: '#/components/schemas/ErrorMessage'

When I try adding the header via the .yaml and try to regenerate the server module, I get this error:

-attribute paths.'/pipelines'(get).responses.200.Access-Control-Allow-Origin is not of type `object

I also tried installing and importing flask_cors in the main.py of the server module.

#!/usr/bin/env python3

import connexion

from openapi_server import encoder
from flask_cors import CORS

def main():
    app = connexion.App(__name__, specification_dir='./openapi/')
    CORS(app.app)
    app.app.json_encoder = encoder.JSONEncoder
    app.add_api('openapi.yaml',
                arguments={'title': 'ICDR API'},
                pythonic_params=True)
    app.run(port=5050)


if __name__ == '__main__':
    main()

And I tried both those together. These fixes I found in the swagger-codegen petstore.yaml example and in the connexion docs.

However as I stated I'm using openapi-generator so its a little different than either of those other tools, but I'm having a lot of trouble finding any information on how to set this up correctly. Has anyone worked with openapi-generator before who can help me out?

Answer 1

OpenApi code generator uses the connexion library under the hood, in their documentation they propose using flask_cors see: here

I am currently using custom mustache templates forked from the originals, so in the \__main__.mustache I added the lines

from flask_cors import CORS
....
CORS(app.app)
app.run(port=.....)

make sure to install flask_cors or add it to your requirements.txt

P.S. you can specify the template location with generate ... -t TEMPALTE/FOLDER?LOCATION