Remote API , ClientLogin to Oauth2.0

Question

I am using RemoteAPI for google authentication (using ClientLogin , which is deprecated) on app -engine. I want to change it to Oauth2.0 . I had googled a lot, but hadn't found much explanation. Any kind of help will be appreciated.

public abstract class RemoteApiClient {

    protected void doOperationRemotely() throws IOException {
        TestProperties testProperties = TestProperties.inst();

        System.out.println("--- Starting remote operation ---");
        System.out.println("Going to connect to:"
                + testProperties.PROJECT_REMOTEAPI_APP_DOMAIN + ":"
                + testProperties.PROJECT_REMOTEAPI_APP_PORT);

        RemoteApiOptions options = new RemoteApiOptions().server(
                testProperties.PROJECT_REMOTEAPI_APP_DOMAIN,
                testProperties.PROJECT_REMOTEAPI_APP_PORT).credentials(
                testProperties.TEST_ADMIN_ACCOUNT,
                testProperties.TEST_ADMIN_PASSWORD);

        RemoteApiInstaller installer = new RemoteApiInstaller();
        installer.install(options);
        try {
            doOperation();
        } finally {
            installer.uninstall();
        }

        System.out.println("--- Remote operation completed ---");
    }

}

Answer 1

For OAuth2 authentication you have two main solutions inside of gcloud.

gcloud

Install gcloud (https://cloud.google.com/sdk/), and then init it (https://cloud.google.com/sdk/docs/initializing). After that, you should go and run "gcloud auth login" which will prompt you an authentication window for connected accounts on gmail.

Your other soulution is creating a new service account through googles console, furnish it a json key and pass it as a credential in a function parameter or set it in GOOGLE_APPLICATION_CREDENTIALS environment variable or use gcloud auth activatve-service-account --key-file "PATH_TO_JSON".

Tutorial to create service account: https://developers.google.com/identity/protocols/OAuth2ServiceAccount#overview

The main advantage of gcloud default authentication over service account(described below) is that every google cloud product will check for the application_credentials.json(well_known_file) file in a constant location. The other advantage is that its token could be refreshed during more than an hour session.