--- /usr/lib/python2.7/dist-packages/duplicity/backends/pydrivebackend.py	2015-05-12 16:12:53.000000000 +0100
+++ pydrive2backend.py	2015-05-28 15:57:16.460856110 +0100
@@ -23,7 +23,7 @@
 from duplicity.errors import BackendException
 
 
-class PyDriveBackend(duplicity.backend.Backend):
+class PyDrive2Backend(duplicity.backend.Backend):
     """Connect to remote store using PyDrive API"""
 
     def __init__(self, parsed_url):
@@ -32,22 +32,38 @@
             global pydrive
             import httplib2
             from apiclient.discovery import build
-            from oauth2client.client import SignedJwtAssertionCredentials
             from pydrive.auth import GoogleAuth
             from pydrive.drive import GoogleDrive
         except ImportError:
-            raise BackendException('PyDrive backend requires PyDrive installation'
+            raise BackendException('PyDrive2 backend requires PyDrive installation. '
                                    'Please read the manpage to fix.')
 
-        if 'GOOGLE_DRIVE_ACCOUNT_KEY' not in os.environ:
-            raise BackendException('GOOGLE_DRIVE_ACCOUNT_KEY environment variable not set. Please read the manpage to fix.')
-        account_key = os.environ['GOOGLE_DRIVE_ACCOUNT_KEY']
+        if 'GOOGLE_DRIVE_AUTH_DIRECTORY' not in os.environ:
+            raise BackendException('PyDrive2 backend requires GOOGLE_DRIVE_AUTH_DIRECTORY environment variable to be set.')
 
-        credentials = SignedJwtAssertionCredentials(parsed_url.username + '@' + parsed_url.hostname, account_key, scope='https://www.googleapis.com/auth/drive')
-        credentials.authorize(httplib2.Http())
+        try:
+            auth_dir = os.environ['GOOGLE_DRIVE_AUTH_DIRECTORY']
+            os.chdir(auth_dir)
+        except:
+            raise BackendException('PyDrive2 backend could not change to auth directory GOOGLE_DRIVE_AUTH_DIRECTORY=' + auth_dir)
+
+        try:
+            f=open('client_secrets.json')
+        except:
+            raise BackendException('PyDrive2 backend failed to open client_secrets.json. '
+                                   'To generate this file see http://pythonhosted.org/PyDrive/quickstart.html')
+            
+
+        auth_file = 'auth.json'
+        
+        try:
         gauth = GoogleAuth()
-        gauth.credentials = credentials
+            if not gauth.LoadCredentialsFile(auth_file) :
+                gauth.CommandLineAuth()
+                gauth.SaveCredentialsFile(auth_file)
         self.drive = GoogleDrive(gauth)
+        except:
+            raise BackendException('PyDrive2 backend authentication using ' + auth_dir + ' failed.')
 
         # Dirty way to find root folder id
         file_list = self.drive.ListFile({'q': "'Root' in parents"}).GetList()
@@ -104,5 +120,5 @@
             size = -1
         return {'size': size}
 
-duplicity.backend.register_backend('pydrive', PyDriveBackend)
-duplicity.backend.uses_netloc.extend(['pydrive'])
+duplicity.backend.register_backend('pydrive2', PyDrive2Backend)
+duplicity.backend.uses_netloc.extend(['pydrive2'])