我试图实现谷歌OAuth流使用指南从谷歌开发控制台。然而，代码在代码中的fetch_token块处失败，我无法前进。
嘿，👋我试图实现谷歌OAuth流使用指南从谷歌开发控制台。然而，代码在代码中的fetch_token块处失败，我无法前进。
https://developers.google.com/identity/protocols/oauth2/web-server#offline

import flask,os
import requests
import waitress
import google.oauth2.credentials
import google_auth_oauthlib.flow
import googleapiclient.discovery
from urllib import parse

# This variable specifies the name of a file that contains the OAuth 2.0
# information for this application, including its client_id and client_secret.
CLIENT_SECRETS_FILE = "client_secret.json"

# This OAuth 2.0 access scope allows for full read/write access to the
# authenticated user's account and requires requests to use an SSL connection.
SCOPES = ['https://www.googleapis.com/auth/drive.metadata.readonly']
API_SERVICE_NAME = 'drive'
API_VERSION = 'v3'

app = flask.Flask(__name__)
# Note: A secret key is included in the sample so that it works.
# If you use this code in your application, replace this with a truly secret
# key. See https://flask.palletsprojects.com/quickstart/#sessions.
app.secret_key = 'REPLACE ME - this value is here as a placeholder.'

@app.route('/')
def index():
  return print_index_table()

@app.route('/test')
def test_api_request():
  if 'credentials' not in flask.session:
    return flask.redirect('authorize')

  # Load credentials from the session.
  credentials = google.oauth2.credentials.Credentials(
      **flask.session['credentials'])

  drive = googleapiclient.discovery.build(
      API_SERVICE_NAME, API_VERSION, credentials=credentials)

  files = drive.files().list().execute()

  # Save credentials back to session in case access token was refreshed.
  # ACTION ITEM: In a production app, you likely want to save these
  #              credentials in a persistent database instead.
  flask.session['credentials'] = credentials_to_dict(credentials)

  return flask.jsonify(**files)

@app.route('/authorize')
def authorize():
  # Create flow instance to manage the OAuth 2.0 Authorization Grant Flow steps.
  flow = google_auth_oauthlib.flow.Flow.from_client_secrets_file(
      CLIENT_SECRETS_FILE, scopes=SCOPES)

  # The URI created here must exactly match one of the authorized redirect URIs
  # for the OAuth 2.0 client, which you configured in the API Console. If this
  # value doesn't match an authorized URI, you will get a 'redirect_uri_mismatch'
  # error.
  flow.redirect_uri = flask.url_for('oauth2callback', _external=True)

  authorization_url, state = flow.authorization_url(
      # Enable offline access so that you can refresh an access token without
      # re-prompting the user for permission. Recommended for web server apps.
      access_type='offline',
      # Enable incremental authorization. Recommended as a best practice.
      include_granted_scopes='true')

  # Store the state so the callback can verify the auth server response.
  flask.session['state'] = state

  return flask.redirect(authorization_url)

@app.route('/oauth2callback')
def oauth2callback():
  # Specify the state when creating the flow in the callback so that it can
  # verified in the authorization server response.
  state = flask.session['state']

  flow = google_auth_oauthlib.flow.Flow.from_client_secrets_file(
      CLIENT_SECRETS_FILE, scopes=SCOPES, state=state)
  flow.redirect_uri = flask.url_for('oauth2callback', _external=True)

  # Use the authorization server's response to fetch the OAuth 2.0 tokens.
  authorization_response = flask.request.url
  flow.fetch_token(authorization_response=authorization_response)

  # Store credentials in the session.
  # ACTION ITEM: In a production app, you likely want to save these
  #              credentials in a persistent database instead.
  credentials = flow.credentials
  flask.session['credentials'] = credentials_to_dict(credentials)

  return flask.redirect(flask.url_for('test_api_request'))

@app.route('/revoke')
def revoke():
  if 'credentials' not in flask.session:
    return ('You need to <a href="/authorize">authorize</a> before ' +
            'testing the code to revoke credentials.')

  credentials = google.oauth2.credentials.Credentials(
    **flask.session['credentials'])

  revoke = requests.post('https://oauth2.googleapis.com/revoke',
      params={'token': credentials.token},
      headers = {'content-type': 'application/x-www-form-urlencoded'})

  status_code = getattr(revoke, 'status_code')
  if status_code == 200:
    return('Credentials successfully revoked.' + print_index_table())
  else:
    return('An error occurred.' + print_index_table())

@app.route('/clear')
def clear_credentials():
  if 'credentials' in flask.session:
    del flask.session['credentials']
  return ('Credentials have been cleared.<br><br>' +
          print_index_table())

def credentials_to_dict(credentials):
  return {'token': credentials.token,
          'refresh_token': credentials.refresh_token,
          'token_uri': credentials.token_uri,
          'client_id': credentials.client_id,
          'client_secret': credentials.client_secret,
          'scopes': credentials.scopes}

def print_index_table():
  return ('<table>' +
          '<tr><td><a href="/test">Test an API request</a></td>' +
          '<td>Submit an API request and see a formatted JSON response. ' +
          '    Go through the authorization flow if there are no stored ' +
          '    credentials for the user.</td></tr>' +
          '<tr><td><a href="/authorize">Test the auth flow directly</a></td>' +
          '<td>Go directly to the authorization flow. If there are stored ' +
          '    credentials, you still might not be prompted to reauthorize ' +
          '    the application.</td></tr>' +
          '<tr><td><a href="/revoke">Revoke current credentials</a></td>' +
          '<td>Revoke the access token associated with the current user ' +
          '    session. After revoking credentials, if you go to the test ' +
          '    page, you should see an <code>invalid_grant</code> error.' +
          '</td></tr>' +
          '<tr><td><a href="/clear">Clear Flask session credentials</a></td>' +
          '<td>Clear the access token currently stored in the user session. ' +
          '    After clearing the token, if you <a href="/test">test the ' +
          '    API request</a> again, you should go back to the auth flow.' +
          '</td></tr></table>')

if __name__ == '__main__':
  # When running locally, disable OAuthlib's HTTPs verification.
  # ACTION ITEM for developers:
  #     When running in production *do not* leave this option enabled.
  os.environ['OAUTHLIB_INSECURE_TRANSPORT'] = '1'

  # Specify a hostname and port that are set as a valid redirect URI
  # for your API project in the Google API Console.
  waitress.serve(app, port="8080", url_scheme="https")

console.log

ERROR:main:Exception on /oauth2callback [GET]
Traceback (most recent call last):
  File "/opt/virtualenvs/python3/lib/python3.8/site-packages/flask/app.py", line 2070, in wsgi_app
    response = self.full_dispatch_request()
  File "/opt/virtualenvs/python3/lib/python3.8/site-packages/flask/app.py", line 1515, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/opt/virtualenvs/python3/lib/python3.8/site-packages/flask/app.py", line 1513, in full_dispatch_request
    rv = self.dispatch_request()
  File "/opt/virtualenvs/python3/lib/python3.8/site-packages/flask/app.py", line 1499, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
  File "main.py", line 91, in oauth2callback
    flow.fetch_token(authorization_response=authorization_response)
  File "/opt/virtualenvs/python3/lib/python3.8/site-packages/google_auth_oauthlib/flow.py", line 288, in fetch_token
    return self.oauth2session.fetch_token(self.client_config["token_uri"], **kwargs)
  File "/opt/virtualenvs/python3/lib/python3.8/site-packages/requests_oauthlib/oauth2_session.py", line 360, in fetch_token
    self._client.parse_request_body_response(r.text, scope=self.scope)
  File "/opt/virtualenvs/python3/lib/python3.8/site-packages/oauthlib/oauth2/rfc6749/clients/base.py", line 429, in parse_request_body_response
    self.token = parse_token_response(body, scope=scope)
  File "/opt/virtualenvs/python3/lib/python3.8/site-packages/oauthlib/oauth2/rfc6749/parameters.py", line 425, in parse_token_response
    validate_token_parameters(params)
  File "/opt/virtualenvs/python3/lib/python3.8/site-packages/oauthlib/oauth2/rfc6749/parameters.py", line 455, in validate_token_parameters
    raise w
Warning: Scope has changed from "https://www.googleapis.com/auth/drive.metadata.readonly" to "https://www.googleapis.com/auth/gmail.readonly https://www.googleapis.com/auth/userinfo.profile https://www.googleapis.com/auth/userinfo.email openid https://www.googleapis.com/auth/drive.metadata.readonly".