Allow authorization via XOAUTH2 using access token

Signed-off-by: Slava Kardakov <ojab@ojab.ru>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

offlineimap.conf

@@ -769,7 +769,8 @@ remoteuser = username
 # with type = IMAP for compatible servers).
 #
 # Mandatory parameters are "oauth2_client_id", "oauth2_client_secret" and
-# "oauth2_refresh_token". See below to learn how to get those.
+# either "oauth2_refresh_token" or "oauth2_access_token".
+# See below to learn how to get those.
 #
 # Specify the OAuth2 client id and secret to use for the connection..
 # Here's how to register an OAuth2 client for Gmail, as of 10-2-2016:
@@ -791,8 +792,12 @@ remoteuser = username
 #    - Type the following command-line in a terminal and follow the instructions
 #         python python/oauth2.py --generate_oauth2_token \
 #            --client_id=YOUR_CLIENT_ID --client_secret=YOUR_CLIENT_SECRET
+#    - Access token can be obtained using refresh token with command
+#         python python/oauth2.py --user=YOUR_EMAIL --client_id=YOUR_CLIENT_ID
+#            --client_secret=YOUR_CLIENT_SECRET --refresh_token=REFRESH_TOKEN
 #
 #oauth2_refresh_token = REFRESH_TOKEN
+#oauth2_access_token = ACCESS_TOKEN
 
 ########## Passwords
 

offlineimap/imapserver.py

@@ -95,10 +95,10 @@ class IMAPServer:
         self.tlslevel = repos.gettlslevel()
 
         self.oauth2_refresh_token = repos.getoauth2_refresh_token()
+        self.oauth2_access_token = repos.getoauth2_access_token()
         self.oauth2_client_id = repos.getoauth2_client_id()
         self.oauth2_client_secret = repos.getoauth2_client_secret()
         self.oauth2_request_url = repos.getoauth2_request_url()
-        self.oauth2_access_token = None
 
         self.delim = None
         self.root = None
@@ -212,7 +212,7 @@ class IMAPServer:
 
 
     def __xoauth2handler(self, response):
-        if self.oauth2_refresh_token is None:
+        if self.oauth2_refresh_token is None and self.oauth2_access_token is None:
             return None
 
         if self.oauth2_access_token is None:

offlineimap/repository/IMAP.py

@@ -276,6 +276,9 @@ class IMAPRepository(BaseRepository):
     def getoauth2_refresh_token(self):
         return self.getconf('oauth2_refresh_token', None)
 
+    def getoauth2_access_token(self):
+        return self.getconf('oauth2_access_token', None)
+
     def getoauth2_client_id(self):
         return self.getconf('oauth2_client_id', None)