Handle OAuth2 AuthorizationExceptions in pub.

utils/pub/oauth2.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library oauth2;
 
 import 'dart:io';
 import 'dart:uri';
 
 // TODO(nweiz): Make this a "package:" URL, or something nicer than this.
@@ skipping 29 matching lines @@
     'https://accounts.google.com/o/oauth2/token');
 
 /// The OAuth2 scopes that the pub client needs. Currently the client only needs
 /// the user's email so that the server can verify their identity.
 final _scopes = ['https://www.googleapis.com/auth/userinfo.email'];
 
 /// An in-memory cache of the user's OAuth2 credentials. This should always be
 /// the same as the credentials file stored in the system cache.
 Credentials _credentials;
 
+/// Delete the cached credentials, if they exist.
+Future clearCredentials(SystemCache cache) {
+  _credentials = null;
+  var credentialsFile = _credentialsFile(cache);
+  return fileExists(credentialsFile).chain((exists) {
+    if (exists) return deleteFile(credentialsFile);
+    return new Future.immediate(null);
+  });
+}
+
 /// Asynchronously passes an OAuth2 [Client] to [fn], and closes the client when
 /// the [Future] returned by [fn] completes.
 ///
 /// This takes care of loading and saving the client's credentials, as well as
 /// prompting the user for their authorization.
 Future withClient(SystemCache cache, Future fn(Client client)) {
   return _getClient(cache).chain((client) {
     var completer = new Completer();
     var future = fn(client);
     future.onComplete((_) {
@@ skipping 113 matching lines @@
   print('Pub needs your authorization to upload packages on your behalf.\n'
         'In a web browser, go to $authUrl\n'
         'Then click "Allow access".\n\n'
         'Waiting for your authorization...');
 
   return completer.future.transform((client) {
     print('Successfully authorized.\n');
     return client;
   });
 }