استفاده از OAuth 2.0 برای برنامه های کاربردی وب سرور

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

import os
import flask
import json
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"

# The OAuth 2.0 access scope allows for access to the
# authenticated user's account and requires requests to use an SSL connection.
SCOPES = ['https://www.googleapis.com/auth/drive.metadata.readonly',
          'https://www.googleapis.com/auth/calendar.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('/drive')
def drive_api_request():
  if 'credentials' not in flask.session:
    return flask.redirect('authorize')

  features = flask.session['features']

  if features['drive']:
    # Load client secrets from the server-side file.
    with open(CLIENT_SECRETS_FILE, 'r') as f:
        client_config = json.load(f)['web']

    # Load user-specific credentials from browser session storage.
    session_credentials = flask.session['credentials']

    # Reconstruct the credentials object.
    credentials = google.oauth2.credentials.Credentials(
        refresh_token=session_credentials.get('refresh_token'),
        scopes=session_credentials.get('granted_scopes'),
        token=session_credentials.get('token'),
        client_id=client_config.get('client_id'),
        client_secret=client_config.get('client_secret'),
        token_uri=client_config.get('token_uri'))

    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.
    flask.session['credentials'] = credentials_to_dict(credentials)

    return flask.jsonify(**files)
  else:
    # User didn't authorize read-only Drive activity permission.
    return '<p>Drive feature is not enabled.</p>'

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

  features = flask.session['features']

  if features['calendar']:
    # User authorized Calendar read permission.
    # Calling the APIs, etc.
    return ('<p>User granted the Google Calendar read permission. '+
            'This sample code does not include code to call Calendar</p>')
  else:
    # User didn't authorize Calendar read permission.
    # Update UX and application accordingly
    return '<p>Calendar feature is not enabled.</p>'

@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
  
  credentials = credentials_to_dict(credentials)
  flask.session['credentials'] = credentials

  # Check which scopes user granted
  features = check_granted_scopes(credentials)
  flask.session['features'] = features
  return flask.redirect('/')
  
@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.')

  # Load client secrets from the server-side file.
  with open(CLIENT_SECRETS_FILE, 'r') as f:
      client_config = json.load(f)['web']

  # Load user-specific credentials from the session.
  session_credentials = flask.session['credentials']

  # Reconstruct the credentials object.
  credentials = google.oauth2.credentials.Credentials(
      refresh_token=session_credentials.get('refresh_token'),
      scopes=session_credentials.get('granted_scopes'),
      token=session_credentials.get('token'),
      client_id=client_config.get('client_id'),
      client_secret=client_config.get('client_secret'),
      token_uri=client_config.get('token_uri'))

  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:
    # Clear the user's session credentials after successful revocation
    if 'credentials' in flask.session:
        del flask.session['credentials']
        del flask.session['features']
    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,
          'granted_scopes': credentials.granted_scopes}

def check_granted_scopes(credentials):
  features = {}
  if 'https://www.googleapis.com/auth/drive.metadata.readonly' in credentials['granted_scopes']:
    features['drive'] = True
  else:
    features['drive'] = False

  if 'https://www.googleapis.com/auth/calendar.readonly' in credentials['granted_scopes']:
    features['calendar'] = True
  else:
    features['calendar'] = False

  return features

def print_index_table():
  return ('<table>' + 
          '<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="/drive">Call Drive API directly</a></td>' +
          '<td> Use stored credentials to call the API, you still might not be prompted to reauthorize ' +
          '    the application.</td></tr>' +
          '<tr><td><a href="/calendar">Call Calendar API directly</a></td>' +
          '<td> Use stored credentials to call the API, 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="/authorize">authorize</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'

  # This disables the requested scopes and granted scopes check.
  # If users only grant partial request, the warning would not be thrown.
  os.environ['OAUTHLIB_RELAX_TOKEN_SCOPE'] = '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)

require 'googleauth'
require 'googleauth/web_user_authorizer'
require 'googleauth/stores/redis_token_store'

require 'google/apis/drive_v3'
require 'google/apis/calendar_v3'

require 'sinatra'

configure do
  enable :sessions

  # Required, call the from_file method to retrieve the client ID from a
  # client_secret.json file.
  set :client_id, Google::Auth::ClientId.from_file('/path/to/client_secret.json')

  # Required, scope value
  # Access scopes for two non-Sign-In scopes: Read-only Drive activity and Google Calendar.
  scope = ['Google::Apis::DriveV3::AUTH_DRIVE_METADATA_READONLY',
           'Google::Apis::CalendarV3::AUTH_CALENDAR_READONLY']

  # Required, Authorizers require a storage instance to manage long term persistence of
  # access and refresh tokens.
  set :token_store, Google::Auth::Stores::RedisTokenStore.new(redis: Redis.new)

  # Required, indicate where the API server will redirect the user after the user completes
  # the authorization flow. The redirect URI is required. The value 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.
  set :callback_uri, '/oauth2callback'

  # To use OAuth2 authentication, we need access to a CLIENT_ID, CLIENT_SECRET, AND REDIRECT_URI
  # from the client_secret.json file. To get these credentials for your application, visit
  # https://console.cloud.google.com/apis/credentials.
  set :authorizer, Google::Auth::WebUserAuthorizer.new(settings.client_id, settings.scope,
                          settings.token_store, callback_uri: settings.callback_uri)
end

get '/' do
  # NOTE: Assumes the user is already authenticated to the app
  user_id = request.session['user_id']

  # Fetch stored credentials for the user from the given request session.
  # nil if none present
  credentials = settings.authorizer.get_credentials(user_id, request)

  if credentials.nil?
    # Generate a url that asks the user to authorize requested scope(s).
    # Then, redirect user to the url.
    redirect settings.authorizer.get_authorization_url(request: request)
  end
  
  # User authorized the request. Now, check which scopes were granted.
  if credentials.scope.include?(Google::Apis::DriveV3::AUTH_DRIVE_METADATA_READONLY)
    # User authorized read-only Drive activity permission.
    # Example of using Google Drive API to list filenames in user's Drive.
    drive = Google::Apis::DriveV3::DriveService.new
    files = drive.list_files(options: { authorization: credentials })
    "<pre>#{JSON.pretty_generate(files.to_h)}</pre>"
  else
    # User didn't authorize read-only Drive activity permission.
    # Update UX and application accordingly
  end

  # Check if user authorized Calendar read permission.
  if credentials.scope.include?(Google::Apis::CalendarV3::AUTH_CALENDAR_READONLY)
    # User authorized Calendar read permission.
    # Calling the APIs, etc.
  else
    # User didn't authorize Calendar read permission.
    # Update UX and application accordingly
  end
end

# Receive the callback from Google's OAuth 2.0 server.
get '/oauth2callback' do
  # Handle the result of the oauth callback. Defers the exchange of the code by
  # temporarily stashing the results in the user's session.
  target_url = Google::Auth::WebUserAuthorizer.handle_auth_callback_deferred(request)
  redirect target_url
end

import json
import flask
import requests

app = flask.Flask(__name__)

# To get these credentials (CLIENT_ID CLIENT_SECRET) and for your application, visit
# https://console.cloud.google.com/apis/credentials.
CLIENT_ID = '123456789.apps.googleusercontent.com'
CLIENT_SECRET = 'abc123'  # Read from a file or environmental variable in a real app

# Access scopes for two non-Sign-In scopes: Read-only Drive activity and Google Calendar.
SCOPE = 'https://www.googleapis.com/auth/drive.metadata.readonly https://www.googleapis.com/auth/calendar.readonly'

# Indicate where the API server will redirect the user after the user completes
# the authorization flow. The redirect URI is required. The value 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.
REDIRECT_URI = 'http://example.com/oauth2callback'

@app.route('/')
def index():
  if 'credentials' not in flask.session:
    return flask.redirect(flask.url_for('oauth2callback'))

  credentials = json.loads(flask.session['credentials'])

  if credentials['expires_in'] <= 0:
    return flask.redirect(flask.url_for('oauth2callback'))
  else: 
    # User authorized the request. Now, check which scopes were granted.
    if 'https://www.googleapis.com/auth/drive.metadata.readonly' in credentials['scope']:
      # User authorized read-only Drive activity permission.
      # Example of using Google Drive API to list filenames in user's Drive.
      headers = {'Authorization': 'Bearer {}'.format(credentials['access_token'])}
      req_uri = 'https://www.googleapis.com/drive/v2/files'
      r = requests.get(req_uri, headers=headers).text
    else:
      # User didn't authorize read-only Drive activity permission.
      # Update UX and application accordingly
      r = 'User did not authorize Drive permission.'

    # Check if user authorized Calendar read permission.
    if 'https://www.googleapis.com/auth/calendar.readonly' in credentials['scope']:
      # User authorized Calendar read permission.
      # Calling the APIs, etc.
      r += 'User authorized Calendar permission.'
    else:
      # User didn't authorize Calendar read permission.
      # Update UX and application accordingly
      r += 'User did not authorize Calendar permission.'

  return r

@app.route('/oauth2callback')
def oauth2callback():
  if 'code' not in flask.request.args:
    state = str(uuid.uuid4())
    flask.session['state'] = state
    # Generate a url that asks permissions for the Drive activity
    # and Google Calendar scope. Then, redirect user to the url.
    auth_uri = ('https://accounts.google.com/o/oauth2/v2/auth?response_type=code'
                '&client_id={}&redirect_uri={}&scope={}&state={}').format(CLIENT_ID, REDIRECT_URI,
                                                                          SCOPE, state)
    return flask.redirect(auth_uri)
  else:
    if 'state' not in flask.request.args or flask.request.args['state'] != flask.session['state']:
      return 'State mismatch. Possible CSRF attack.', 400

    auth_code = flask.request.args.get('code')
    data = {'code': auth_code,
            'client_id': CLIENT_ID,
            'client_secret': CLIENT_SECRET,
            'redirect_uri': REDIRECT_URI,
            'grant_type': 'authorization_code'}

    # Exchange authorization code for access and refresh tokens (if access_type is offline)
    r = requests.post('https://oauth2.googleapis.com/token', data=data)
    flask.session['credentials'] = r.text
    return flask.redirect(flask.url_for('index'))

if __name__ == '__main__':
  import uuid
  app.secret_key = str(uuid.uuid4())
  app.debug = False
  app.run()