Cloud endpoints authentication failure in android app

Question

I'm having trouble with my first attempt to use authentication in debug mode in a Google Cloud Endpoints android app. I set up credentials like this:

credential = GoogleAccountCredential.usingAudience(this,
           "server:client_id:long-string-i-got-from-api-console");
credential.setSelectedAccountName(accountName);

then try to use it like this:

final String LOCAL_APP_ENGINE_SERVER_URL = "http://xxx.xxx.x.xxx:8888"; 
Testdbendpoint.Builder endpointBuilder = new Testdbendpoint.Builder(
            AndroidHttp.newCompatibleTransport(),
            new GsonFactory(),
            credential);
endpointBuilder.setRootUrl(LOCAL_APP_ENGINE_SERVER_URL + "/_ah/api/");
Testdbendpoint endpoint = endpointBuilder.build();
try {
    TestDB testDB = new TestDB().setId(10101L);                      
    TestDB result = endpoint.insertTestDB(testDB).execute();  //-- fails here!!!!
} catch ...

But the try fails and I get these messages in logCat:

03-06 23:33:20.418: W/System.err(11861): Caused by: com.google.android.gms.auth.GoogleAuthException: Unknown 03-06 23:33:20.418: W/System.err(11861): at com.google.android.gms.auth.GoogleAuthUtil.getToken(Unknown Source) 03-06 23:33:20.423: W/System.err(11861): at com.google.android.gms.auth.GoogleAuthUtil.getToken(Unknown Source) 03-06 23:33:20.428: W/System.err(11861): at com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential.getToken(GoogleAccountCredential.java:192)

Answer 1

Maybe you have the wrong Certificate fingerprint (SHA1) for your Android Client-Id? The authentication with the fingerprint of your production key works only if you sign the .apk manually.

Register a Client-Id for an Installed Application (Android) with your debug.keystore fingerprint in your API Console. To get the fingerprint use:

C:\>keytool -list -alias androiddebugkey -keystore C:\.android\debug.keystore -storepass android -keypass android

Also you need a Web-Client-Id and set it as Audience in your Android application:

credential = GoogleAccountCredential.usingAudience(this,"server:client_id:" + WEB_CLIENT_ID);

AppEngine Endpoint configuration should look like this:

@Api(
    name = "testEndpoint",
    version = "v1",
    clientIds = {ClientIds.WEB_ID, ClientIds.ANDROID_PRODUCTION_ID, ClientIds.ANDROID_DEBUG_ID},
    audiences = {ClientIds.WEB_ID}

)