Flaskセッションでurlfetchコンテンツの割り当てが許可されない - 内部サーバーエラー

Question

私はGoogle App Engine上でPythonアプリケーションを実行しています。 oauthライブラリを使用せずにOauth 2認証を実行しようとしています。

Googleの認証コード（アクセストークン）から返された情報を保存し、次のリクエストに送信するセッションが必要です。フラスコのセッションキーにJSONを保存しようとすると、私のアプリはデバッグ情報なしで内部サーバーエラーになります。私のコードは、Oauth2のWebサーバーアプリケーションのドキュメント（コードにリンクされているリンク）用に、実際にはGoogleのHTTP Restサンプルのコピー貼りです。

import logging 
import flask 
from flask import render_template, session 
import json 
import urllib 
from google.appengine.api import urlfetch 
#Code from https://developers.google.com/identity/protocols/OAuth2WebServer 

app = flask.Flask(__name__) 

CLIENT_ID = '[].apps.googleusercontent.com' 
CLIENT_SECRET = '[]' 
SCOPE = 'email' 
REDIRECT_URI = 'https://[].appspot.com/oauthcallback' 

#check for last oauth step, if not go to intermediate steps 
@app.route('/') 
def index(): 
    if 'credentials' not in flask.session: 
     return flask.render_template('index.html') 
    credentials = json.loads(flask.session['credentials']) 
    if credentials['expires_in'] <= 0: 
     return flask.redirect(flask.url_for('oauthcallback')) 
    else: 
     headers = {'Authorization': 'Bearer {}'.format(credentials['access_token'])} 
     req_uri = 'https://www.googleapis.com/oauth2/v2/userinfo' 
     r = requests.get(req_uri, headers=headers) 
     return r.text 

#ask user to sign in, send code to googleapi to get token 
@app.route('/oauthcallback') 
def oauthcallback(): 
    if 'code' not in flask.request.args: 
     auth_uri = ('https://accounts.google.com/o/oauth2/v2/auth?response_type=code&client_id={}&redirect_uri={}&scope={}').format(CLIENT_ID, REDIRECT_URI, SCOPE) 
     return flask.redirect(auth_uri) 
    else: 
     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'} 
     r = urlfetch.fetch("https://www.googleapis.com/oauth2/v4/token", payload=data, method="POST") 
     #return r.content #prints json 
     flask.session['credentials'] = r.content #breaks here 
     return flask.redirect(flask.url_for('index')) 


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

Answer 1

リダイレクトURIを有効にしましたか？

https://developers.google.com/api-client-library/python/auth/web-app

Create authorization credentials 
Any application that uses OAuth 2.0 to access Google APIs must have authorization credentials that identify the application to Google's OAuth 2.0 server. The following steps explain how to create credentials for your project. Your applications can then use the credentials to access APIs that you have enabled for that project. 

Open the Credentials page in the API Console. 
Click Create credentials > OAuth client ID. 
Complete the form. Set the application type to Web application. Applications that use languages and frameworks like PHP, Java, Python, Ruby, and .NET must specify authorized redirect URIs. The redirect URIs are the endpoints to which the OAuth 2.0 server can send responses. 

For testing, you can specify URIs that refer to the local machine, such as http://localhost:8080. With that in mind, please note that all of the examples in this document use http://localhost:8080 as the redirect URI.