Refresh access token when using a very old short-lived access token with unknown expiration (dropbox#352)

Co-authored-by: Brent Bumann <bbumann@dropbox.com>

Author: Brent1LT

dropbox/dropbox_client.py

@@ -358,9 +358,10 @@ def check_and_refresh_access_token(self):
  :return:
  """
  can_refresh = self._oauth2_refresh_token and self._app_key
- needs_refresh = self._oauth2_access_token_expiration and \
- (datetime.utcnow() + timedelta(seconds=TOKEN_EXPIRATION_BUFFER)) >= \
- self._oauth2_access_token_expiration
+ needs_refresh = self._oauth2_refresh_token and \
+ (not self._oauth2_access_token_expiration or
+ (datetime.utcnow() + timedelta(seconds=TOKEN_EXPIRATION_BUFFER)) >=
+ self._oauth2_access_token_expiration)
  needs_token = not self._oauth2_access_token
  if (needs_refresh or needs_token) and can_refresh:
  self.refresh_access_token(scope=self._scope)

test/unit/test_dropbox_unit.py

@@ -345,6 +345,18 @@ def test_check_refresh_with_only_refresh(self, session_instance):
  dbx.check_and_refresh_access_token()
  assert session_instance.post.call_count == 1
 
+ def test_refresh_token_with_no_expiration(self, session_instance):
+ # Test refresh token is refreshed when not given expiration
+ dbx = Dropbox(oauth2_access_token=ACCESS_TOKEN,
+ oauth2_refresh_token=REFRESH_TOKEN,
+ oauth2_access_token_expiration=None,
+ app_key=APP_KEY,
+ app_secret=APP_SECRET,
+ session=session_instance)
+ dbx.check_and_refresh_access_token()
+ assert session_instance.post.call_count == 1
+ assert dbx._oauth2_access_token_expiration
+
  def test_check_refresh_with_invalid_grant(self, invalid_grant_session_instance):
  dbx = Dropbox(oauth2_refresh_token=REFRESH_TOKEN,
  app_key=APP_KEY,