Authorizing Google Apps Script to access Drive files - google-apps-script

Question

The code below works fine for getting my own Google+ user attributes:
// Google oAuth
function getAuth(service, scopes) {
var oAuthConfig = UrlFetchApp.addOAuthService(service);
oAuthConfig.setRequestTokenUrl("https://www.google.com/accounts/OAuthGetRequestToken? scope="+scopes);
oAuthConfig.setAuthorizationUrl("https://www.google.com/accounts/OAuthAuthorizeToken");
oAuthConfig.setAccessTokenUrl("https://www.google.com/accounts/OAuthGetAccessToken");
oAuthConfig.setConsumerKey("anonymous");
oAuthConfig.setConsumerSecret("anonymous");
return {oAuthServiceName:service, oAuthUseToken:"always"};
}
function test_API_Key() {
var gPlusAuth = getAuth("plus", "https://www.googleapis.com/auth/plus.me");
var url = "https://www.googleapis.com/plus/v1/people/me?key=" + API_KEY;
var httpResponse = UrlFetchApp.fetch(url, gPlusAuth);
Logger.log(httpResponse);
}
When I use the same approach for accessing metadata about files on my Google Drive, I run into the HTTP error, 403, and "access not configured." Below is the code. What am I doing wrong?
function getFileMetaData(fileId) {
var driveAuth = getAuth("drive", "https://www.googleapis.com/auth/drive");
var url = "https://www.googleapis.com/drive/v2/files/" +
documentID + "?key=" + API_KEY;
var response = UrlFetchApp.fetch(url, driveAuth);
Logger.log(response);
}

Answer 1

Taken from google developer site[1]
At a high-level, all apps follow the same basic authorization pattern:
Register the application in the Google Developers Console.
Request that the user grant access to data in their Google account.
If the user consents, your application requests and receives credentials to access the Drive API.
Refresh the credentials (if necessary).
<script type="text/javascript">
var CLIENT_ID = '<YOUR_CLIENT_ID>';
var SCOPES = [
'https://www.googleapis.com/auth/drive.file',
'https://www.googleapis.com/auth/userinfo.email',
'https://www.googleapis.com/auth/userinfo.profile',
// Add other scopes needed by your application.
];
[1] https://developers.google.com/drive/web/about-auth