Still get CORS error with Flask despite having set headers

Question

I have a Flask app with the following:

app = Flask(__name__)
cors = CORS(app, resources={r"/api/*": {"origins": "*"}})

@app.after_request
def add_headers(response):
    response.headers['Access-Control-Allow-Origin'] = '*'
    response.headers['Access-Control-Allow-Headers'] =  "Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With"
    response.headers['Access-Control-Allow-Methods']=  "POST, GET, PUT, DELETE, OPTIONS"
    return response

# some stuff

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000)

But I still get CORS error in the browser. I am running the app on Gitpod. If I set the port to public it works fine, but I shouldn't have to have a publicly available API endpoint just to get this working on the same server.

Answer 1

If using javascript fetch, fetch does not include credentials by default, you should do fetch("<Your URL>", { credentials: 'include' })