RFC6749 MismatchingStateError

[MHFDoge]

Hi, I have no clue what happened between a week ago and yesterday but over that time something appears to have changed or broken.
The error I get occurs during the authentication flow and has exhausted me of ideas for fixing it.

oauthlib.oauth2.rfc6749.errors.MismatchingStateError: (mismatching_state) CSRF Warning! State not equal in request and response.

I have tried re-downloading the credential file, as well as creating a new credential, both of which resulted in the same error. I'm also unsure what to do to fix this error, or where I should report an issue if necessary.
Any help would be very appreciated. Thank you.

[kuzmoyev]

Hi. Could you please share the code snippet that produces this and the whole traceback?

[MHFDoge]

I am beyond confused, I re-ran the script to get a fresh traceback and it worked without issue. I changed nothing since my last run and it now all of the sudden works.
Here's the traceback and snippet anyway, if it's of any use for the future.

Traceback (most recent call last):
  File "C:\Fakepath\testcal_nuke.py", line 6, in _generate_calendar
    return GoogleCalendar(id)
  File "C:\Fakepath\lib\site-packages\gcsa\google_calendar.py", line 90, in __init__
    self.credentials = self._get_credentials(
  File "C:\Fakepath\lib\site-packages\gcsa\google_calendar.py", line 131, in _get_credentials
    credentials = flow.run_local_server(host=host, port=port)
  File "C:\Fakepath\lib\site-packages\google_auth_oauthlib\flow.py", line 477, in run_local_server
    self.fetch_token(authorization_response=authorization_response)
  File "C:\Fakepath\lib\site-packages\google_auth_oauthlib\flow.py", line 286, in fetch_token
    return self.oauth2session.fetch_token(self.client_config["token_uri"], **kwargs)
  File "C:\Fakepath\lib\site-packages\requests_oauthlib\oauth2_session.py", line 244, in fetch_token
    self._client.parse_request_uri_response(
  File "C:\Fakepath\lib\site-packages\oauthlib\oauth2\rfc6749\clients\web_application.py", line 220, in parse_request_uri_response
    response = parse_authorization_code_response(uri, state=state)
  File "C:\Fakepath\lib\site-packages\oauthlib\oauth2\rfc6749\parameters.py", line 278, in parse_authorization_code_response
    raise MismatchingStateError()
oauthlib.oauth2.rfc6749.errors.MismatchingStateError: (mismatching_state) CSRF Warning! State not equal in request and response.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Fakepath\testcal_nuke.py", line 12, in <module>
    calendar=_generate_calendar("<calendar id>@group.calendar.google.com")#,
  File "C:\Fakepath\testcal_nuke.py", line 7, in _generate_calendar
    except RefreshError as err:
NameError: name 'RefreshError' is not defined

snippet:

def _generate_calendar(id) -> GoogleCalendar:
    try:
        return GoogleCalendar(id)
    except RefreshError as err:
        os.remove("C:/Fakepath/.credentials/token.pickle")
        print(f"Authentication token expired. Reauthenticating...")
        return GoogleCalendar(id)
#...
calendar = _generate_calendar("<calendar id>@group.calendar.google.com")#,

Thank you for your help and for maintaining this library. Very appreciated.