This sample demonstrates using the Oauth2 apis to create an authenticaion filter.

See the Google App Engine standard environment documentation for more detailed instructions.

1. In the Cloud Developers Console > API Manager > Credentials, create a Oauth Client ID for a Web Application. You will need to provide an authroized JavaScript origin. Typically, https://projectID.appspot.com.
2. Edit src/main/webapp/index.html and change YOUR_CLIENT_ID_HERE.apps.googleusercontent.com to Client ID from the prior step.

NOTE: The app can be run locally, but the Oauth2 APIs do not work with the development server.

$ mvn appengine:devserver

$ mvn appengine:update -Dappengine.appId=YOUR-PROJECT-ID -Dappengine.version=SOME-VERSION

1. Using your browser, visit https://YOUR-PROJECT-ID.appspot.com, click Sign In.

2. The Sign In process will then request some text from your app, and then display it, if the id matches the list in src/main/java/com/example/appengine/Oauth2Filter.java.

NOTE: Typically, you would use this for Service Accounts, but user accounts work as well.

1. Enable logging by uncommenting the context.log line in src/main/java/com/example/appengine/Oauth2Filter.java, redeploy, and visit the page

2. Look at the logs in Cloud Developers Console > Logs.

3. Add the tokenAudience to the allowedClients.

4. Deploy and visit the page again.