Google API Oauth code verifier

Пытаюсь обменять code на access_token, но возникают проблемы. А конкретнее:

{ "error": "invalid_grant", "error_description": "Invalid code verifier." }

Мои шаги:

  1. Для получения кода нужно придумать 3 вещи: state, code_verifier и code_challenge. Сгенерим:
from os import urandom
from base64 import encodebytes
from hashlib import sha256 as sha
   
   
def random_data_base64_url(length: int) -> str:
    return base64_url_encode_no_padding(urandom(length))
   
   
def base64_url_encode_no_padding(buffer: bytes) -> str:
    return encodebytes(buffer).decode('UTF-8').replace('+', '-').replace('/', '_').replace('=', 
       '').replace('\n', '')
   
   
def sha256(buffer: str) -> bytes:
    return sha(buffer.encode('ASCII')).hexdigest().encode('UTF-8')
   
state = random_data_base64_url(32)
code_verifier = random_data_base64_url(32)
code_challenge = base64_url_encode_no_padding(sha256(code_verifier))
  1. Так, как у меня веб сервис на flask, то code_verifier и state я закину в session.
  2. Соберем url и закинем 302 на него:
url = "https://accounts.google.com/o/oauth2/v2/auth?response_type=code&scope={}&redirect_uri={}&client_id={}&state={}&code_challenge={}&code_challenge_method={}".format(
        google_conf['auth_endpoint'],
        ' '.join(scope),
        quote(google_conf['redirect_url']),
        google_conf['client_id'],
        state,
        code_challenge,
        google_conf['challenge_method']
    )
return redirect(url, code=302)
  1. После манипуляций клиента, получаем реквест на наш redirect_url, который я указывал шаг назад. Обработаем:
state = request.args.get('state')
code = request.args.get('code')

if not code or not session.get('code_verifier'):
   return 'Bad request', 400
if session['state'] != state:
   return 'Invalid state. Try again.', 400

a = token_handler(code, session['code_verifier'], google_conf['client_secret'], google_conf['client_id'])

return a
  1. Обменяем код на токен:
def proceed_token(code: str, code_verifier: str, client_secret: str, client_id: str, redirect_uri="https://xxx.ru/proceed_token"):
    endpoint = "https://www.googleapis.com/oauth2/v4/token"

    data = {
        "code": code,
        "redirect_uri": redirect_uri,
        "client_id": client_id,
        "code_verifier": code_verifier,
        "client_secret": client_secret,
        "scope": "",
        "grant_type": "authorization_code"
    }

    r = requests.post(url=endpoint, data=data)
    print(r.request.body)
    return r.text

Я проверял в обратку этот самый code_verifier.
То есть, если взять client_challenge, развернуть в шашку и взять еще шашку от изначального code_verifier, то они равны.

Я абсолютно не понимаю в чем дело.

Делаю по примеру отсюда: https://github.com/googlesamples/oauth-apps-for-windows


Ответы (1 шт):

Автор решения: icYFTL

Проблема к сожалению решилась нахождением гайда от гугла.

Готовый вариант:

# -*- coding: utf-8 -*-

import os
import flask
import requests

import google.oauth2.credentials
import google_auth_oauthlib.flow
import googleapiclient.discovery

# 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 = 'v2'

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.
  app.run('localhost', 8080, debug=True)

**взято с https://developers.google.com/identity/protocols/oauth2/web-server#python

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