An alternative to Rob--W/cors-anywhere.

gcf-cors-anywhere is a Node.js proxy which adds CORS headers to the proxied request running on Google Cloud Functions.

The url to proxy is taken from the search params ?u=, validated and proxied.

Tutorial

1. In the Google Cloud Console, on the project selector page, select or create a Google Cloud project.
2. Make sure that billing is enabled for your Cloud project. Learn how to confirm that billing is enabled for your project.
3. Enable the Cloud Functions and Cloud Build APIs.
4. Install and initialize the Cloud SDK.
5. Update gcloud components:

   gcloud components update
   gcloud init

6. Deploy this function. YOU NEED TO CHANGE PROJECT_ID AND GCP_REGION.

   wget https://github.com/taichunmin/gcf-cors-anywhere/archive/master.zip -O gcf-cors-anywhere.zip
   unzip gcf-cors-anywhere.zip
   # YOU NEED TO CHANGE `PROJECT_ID` AND `GCP_REGION`.
   gcloud functions deploy cors-anywhere --allow-unauthenticated --entry-point=main --gen2 --max-instances=1 --memory=128Mi --no-user-output-enabled --project=PROJECT_ID --region=GCP_REGION --runtime=nodejs18 --timeout=60s --trigger-http --source ./gcf-cors-anywhere-master
   # clean up
   # rm -rf ./gcf-cors-anywhere.zip ./gcf-cors-anywhere-master

Use Axios and LINE Login API as example:

// YOU NEED TO CHANGE `PROJECT_ID` AND `GCP_REGION`.
const result = await axios.get('https://GCP_REGION-PROJECT_ID.cloudfunctions.net/cors-anywhere', {
  params: {
    u: 'https://api.line.me/v2/profile', // your real url
    // you can add additional params here
  },
  headers: { Authorization: 'Bearer ACCESS_TOKEN' },
})
console.log(result.data)

// YOU NEED TO CHANGE `PROJECT_ID` AND `GCP_REGION`.
const result = await axios.post('https://GCP_REGION-PROJECT_ID.cloudfunctions.net/cors-anywhere', Qs.stringify({
  client_id: 'CLIENT_ID',
  id_token: 'ID_TOKEN',
  nonce: 'NONCE',
  user_id: 'USER_ID',
}), {
  params: { u: 'https://api.line.me/oauth2/v2.1/verify' }, // your real url
})
console.log(result.data)