Question

我有一个简单的Google App Engine应用，其中包含更新YouTube播放列表的/update页面。它看起来像这样：

class UpdatePage(webapp2.RequestHandler):

    @decorator.oauth_required
    def get(self):
        update_result = self.update_playlist()
        ...

routes = [('/update', UpdatePage),
          (decorator.callback_path, decorator.callback_handler())]
app = webapp2.WSGIApplication(routes, debug=True)

它按预期工作，update_playlist()方法完成其工作，但事实证明，在某些情况下，它可以运行很长时间，从而产生DeadlineExceededError。因此，在阅读了有关可用选项之后，我认为任务队列 API是可行的方法（对吗？），我正在尝试使用它，遵循Using Push Queues in Python指南。

→简而言之，我将UpdatePage分为UpdatePageHandler + UpdatePageWorker：

class UpdateHandlerPage(webapp2.RequestHandler):

    @decorator.oauth_required
    def get(self):
        taskqueue.add(url='/updateworker')

class UpdateWorkerPage(webapp2.RequestHandler):

    def post(self):
        update_result = self.update_playlist()
        ...

routes = [('/update', UpdateHandlerPage),
          ('/updateworker', UpdateWorkerPage),
          (decorator.callback_path, decorator.callback_handler())]
app = webapp2.WSGIApplication(routes, debug=True)

不幸的是，在进行拆分后，似乎我的OAuth2装饰器不再起作用了：

INFO     2013-05-30 17:08:53,971 discovery.py:709] URL being requested: https://www.googleapis.com/youtube/v3/playlists?alt=json&part=snippet%2Cstatus
WARNING  2013-05-30 17:08:53,975 urlfetch_stub.py:480] Stripped prohibited headers from URLFetch request: ['content-length']
INFO     2013-05-30 17:08:54,351 client.py:493] Refreshing due to a 401
INFO     2013-05-30 17:08:54,361 appengine.py:276] make: Got type <class 'google.appengine.api.datastore_types.Blob'>
INFO     2013-05-30 17:08:54,363 appengine.py:289] validate: Got type <class 'oauth2client.client.OAuth2Credentials'>
INFO     2013-05-30 17:08:54,364 client.py:680] Refreshing access_token
INFO     2013-05-30 17:08:54,746 client.py:699] Failed to retrieve access token: {
  "error" : "invalid_grant"
}
INFO     2013-05-30 17:08:54,757 appengine.py:276] make: Got type <class 'google.appengine.api.datastore_types.Blob'>
INFO     2013-05-30 17:08:54,759 appengine.py:289] validate: Got type <class 'oauth2client.client.OAuth2Credentials'>
INFO     2013-05-30 17:08:54,761 appengine.py:289] validate: Got type <class 'oauth2client.client.OAuth2Credentials'>
INFO     2013-05-30 17:08:54,762 appengine.py:265] get: Got type <class 'oauth2client.appengine.CredentialsModel'>

如果不是装饰UpdateHandlerPage:get而是装饰UpdateWorkerPage:post，我会得到一个无限的失败循环：

INFO     2013-05-30 17:24:31,307 discovery.py:190] URL being requested: https://www.googleapis.com/discovery/v1/apis/youtube/v3/rest?userIp=127.0.0.1
INFO     2013-05-30 17:24:34,960 dev_appserver.py:3105] "GET /update HTTP/1.1" 200 -
INFO     2013-05-30 17:24:35,060 dev_appserver.py:3105] "POST /updateworker HTTP/1.1" 302 -
WARNING  2013-05-30 17:24:35,065 taskqueue_stub.py:1980] Task task1 failed to execute. This task will retry in 0.100 seconds
INFO     2013-05-30 17:24:35,240 dev_appserver.py:3105] "POST /updateworker HTTP/1.1" 302 -
WARNING  2013-05-30 17:24:35,245 taskqueue_stub.py:1980] Task task1 failed to execute. This task will retry in 0.200 seconds
...

我该怎么办？谢谢你的帮助！

Answer 1

由于任务队列任务将由您的应用程序生成，因此原始请求中的任何标头都不会被发送。特别是，Cookies标头通过应用程序的SACSID cookie识别您的用户（由App Engine用户API提供）。

更新:(这是在原始帖子之后添加的。）由于没有Cookie，标识用户的SACSID Cookie将不在那里，因此{{1指定将强制重定向（即HTTP decorator.oauth_required）每个时间cron作业运行。

不要试图从装饰器中获取当前用户，而是最好将App Engine用户ID传递给您的任务。首先获取当前用户（在您的装饰方法中）：

然后传递任务中的App Engine用户ID

from google.appengine.api import users
# Guaranteed not to be None by the decorator
current_user = users.get_current_user()

然后在您的任务中，您可以检索import urllib query_string = urllib.urlencode({'user_id': current_user.user_id()}) taskqueue.add(url='/updateworker?' + query_string)

的抓取

user_id

并使用它来获取该用户的凭据as is done in the decorator：

# This is the 'user_id' you appended in the query string
user_id = self.request.get('user_id')

如何在GAE任务队列中执行OAuth操作？

1 个答案: