How do I set up a GCP App Engine instance with CORS?

问题

I've set up two different GCP App Engine apps. One is an express server (let's call it foo) with the following app.yaml:

runtime: nodejs10
handlers:
- url: /tasks
  static_dir: /tasks
  http_headers:
    Access-Control-Allow-Origin: https://bar.appspot.com/
  secure: always

From my bar app, I'm trying to do a fetch call:

const response = await fetch('https://foo.appspot.com/tasks');

Every time I try this, however, Chrome blocks my request with the 'has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.' error. I've also tried just replacing the URL in the http_header with '*' to no avail. Why is this? What am I missing?

Edit: After some more digging, I'm finding that the headers being returned from foo don't even include the Access-Control-Allow-Origin header at all.

Edit 2: I finally bypassed this issue by just using the npm cors package: https://www.npmjs.com/package/cors

回答1:

Finally bypassed this by using the cors package: https://www.npmjs.com/package/cors. Good luck to you all!

回答2:

As of May 2020, I had the same issue, css files being blocked by CORS policy on browser, served by Google cloud storage.

And as addressed in this Gcloud wiki page: https://cloud.google.com/storage/docs/configuring-cors#configure-cors-bucket

It worked for me, by setting the CORS on the G storage bucket.

And don't need the handlers stuff config in app.yaml, and I'm not a big fan of YAML btw...

来源：https://stackoverflow.com/questions/53529968/how-do-i-set-up-a-gcp-app-engine-instance-with-cors