Google Drive API through Google App Engine

Question

I\'m trying to use the Google Drive API through the App Identity interface provided with Google App Engine. This basically allows my web application to communicate with Goog

Answer 1

I think you should at least setup an API console entry with Drive API enabled at https://code.google.com/apis/console Once you create this you'll get an ID you can use in your GoogleCredential object. From the GoogleCredential object you can get the access token which you can than add to your request.

Answer 2

AFAICT you should be using Bearer in the Authorization header.

Probably what's happening is, Drive API doesn't recognize the service account (because of the wrong header?) and thus taking it as an anonymous request since no key parameter wasn't provided either (see common query params).

Try this:

connection.addRequestProperty("Authorization", "Bearer " + accessToken.getAccessToken());

Or you could try adding the token as access_token query param.

Answer 3

What I read here (Google drive via service accounts) was that you use a slightly different style that uses an API KEY that you retrieve from the Developer Console.
The pertinent parts for me were to generate a "Key for Server Applications", then use this technique, which I hadn't read anywhere else!

      HttpTransport httpTransport = new NetHttpTransport();
  JsonFactory jsonFactory = new JacksonFactory();
  AppIdentityCredential credential =
      new AppIdentityCredential.Builder(DriveScopes.DRIVE).build();
  // API_KEY is from the Google Console as a server API key
  GoogleClientRequestInitializer keyInitializer =
      new CommonGoogleClientRequestInitializer(API_KEY);
  Drive service = new Drive.Builder(httpTransport, jsonFactory, null)
      .setHttpRequestInitializer(credential)
      .setGoogleClientRequestInitializer(keyInitializer)
      .build();

Answer 4

This answer claims that:

Service Accounts are not supported by the Drive SDK due to its security model.

If that's still true, one workaround is to perform a regular OAuth dance once with a regular Google Account, and persist the access and refresh token in the datastore.

Answer 5

The 403 error you are getting means that there was no Authorization header in your GET. The logic is that without an Authorization header, you are anonymous (you are legion blah blah :-)). The Drive quota for anonymous use is zero, hence the message. URL shortener has a higher quota for anonymous so it works.

I suggest you change the URL to point to an http server of your own, and check what headers you are actually sending.