https://appengine.google.com/_ah/logout still working?

Question

Until a few days ago I could use the log out from google account procedure mentioned (among several others) in this link.

The recommended log out URL is similar to: https://www.google.com/accounts/Logout?continue=https://appengine.google.com/_ah/logout?continue=http://localhost:4200/index.html

But all of a sudden when navigating to the recommended URL, a redirection notice page appears instead of navigating directly to http://localhost:4200/index.html

In this previous question a similar problem was reported, but also that the problem solved itself shortly after

Can anyone confirm that the log out from google account URL is still working?

Thank you very much

Answer 1

Redirection notice page appearance is the intended behavior of the appengine API.

For security reasons it will no longer work, unless URL will be signed.

Please check documentation, how to sign URL with the appengine API.

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Example: you can find documentation and test it on the API method page. Expanding try this API window, you will get access to example in curl, http and javascript.

You also need to use ?key=<YOUR_API_KEY> part with the secret key for authentication

curl --request POST \
  'https://iamcredentials.googleapis.com/v1/projects/-/serviceAccounts/<service-account-name>%40<project-name>.iam.gserviceaccount.com:signBlob?key=<YOUR_API_KEY>' \
  --header 'Authorization: Bearer <YOUR_ACCESS_TOKEN>' \
  --header 'Accept: application/json' \
  --header 'Content-Type: application/json' \
  --data '{"payload":"<BLOB-TO-SIGN>"}' \
  --compressed