带有 Google 应用引擎的 webapp2 装饰器路由答案

【问题标题】：webapp2 decorator routes with Google app engine带有 Google 应用引擎的 webapp2 装饰器路由
【发布时间】：2012-07-23 14:29:18
【问题描述】：

我想通过装饰我的 RequestHandler 对象来定义路由，而不是在创建应用程序时提供一个列表。

我的 WSGIApplication 定义如下：

class WSGIApplication(webapp2.WSGIApplication):
    def __init__(self, *args, **kwargs):
        super(WSGIApplication, self).__init__(*args, **kwargs)
        self.router.set_dispatcher(self.__class__.custom_dispatcher)

    @staticmethod
    def custom_dispatcher(router, request, response):
        rv = router.default_dispatcher(request, response)
        if isinstance(rv, basestring):
            rv = webapp2.Response(rv)
        elif isinstance(rv, tuple):
            rv = webapp2.Response(*rv)

        return rv

    def route(self, url, name):
        def outer_wrapped(cls):
            logging.info("Adding route %s to class %s with name %s"
                         % (url, cls, name))
            self.router.add(RedirectRoute(url, cls,
                                          name=name,
                                          strict_slash=True))
            return cls
        return outer_wrapped

在package.utils

我在package.application中定义了我的应用程序

app.yaml 有

application: theapplication
version: 1
runtime: python27
api_version: 1
threadsafe: yes

handlers:
- url: .*
  script: package.main.application
  secure: always

package.main如下：

from package.application import application
from package.pages import pages

package.application 如下（密钥散列）：

from package import utils

conf = {}
conf['webapp2_extras.sessions'] = {'secret_key':
    """##############################################"""}

application = utils.WSGIApplication([], config=conf)

这里有几个来自package.pages 的处理程序：

from package.application import application as app


@app.route('/conversations', 'view_messages')
class Messages(BaseHandler):
    @users.require_login
    def get(self):
        conversations = self.current_user.get_user_conversations()
        return self.render('conversations.slim', conversations=conversations)


@app.route('/', 'index')
class Index(BaseHandler):
    def get(self):
        return self.render('index.slim')

索引页工作正常，其他都是 404，日志简单地说：

INFO     2012-07-23 14:23:46,258 __init__.py:26] /notifications
INFO     2012-07-23 14:23:46,272 dev_appserver.py:2952] "GET /notifications HTTP/1.1" 404 -

~~我认为这在某种程度上是由于 appengine 的导入缓存阻止了装饰器运行并将它们自己添加到应用程序中造成的。~~

当然，我陷入了假设我对导致问题的原因有任何线索的陷阱。在尝试每次调度之前，我添加了更多日志语句以输出路由列表，我发现所有路由都在路由器中，正如人们所期望的那样：

    ...
    def custom_dispatcher(router, request, response):
        logging.info(router.match_routes)
        logging.info(router.build_routes)
        rv = router.default_dispatcher(request, response)
    ...

在将我的浏览器指向 /conversations 时显示以下日志输出：

INFO     2012-08-04 13:16:40,513 utils.py:13] [<Route('/friendship', <class 'package.pages.pages.Friendship'>, name='friendship', defaults={}, build_only=False)>, <Route('/friendship/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/friendship', <class 'package.pages.pages.Friendship'>, name='friendship', defaults={}, build_only=False)>>, '_name': 'friendship'}, build_only=False)>, <Route('/signup', <class 'package.pages.pages.Signup'>, name='signup', defaults={}, build_only=False)>, <Route('/signup/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/signup', <class 'package.pages.pages.Signup'>, name='signup', defaults={}, build_only=False)>>, '_name': 'signup'}, build_only=False)>, <Route('/preferences', <class 'package.pages.pages.UserPage'>, name='user_prefs', defaults={}, build_only=False)>, <Route('/preferences/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/preferences', <class 'package.pages.pages.UserPage'>, name='user_prefs', defaults={}, build_only=False)>>, '_name': 'user_prefs'}, build_only=False)>, <Route('/<username:[a-zA-Z]+>', <class 'package.pages.pages.UserPage'>, name='user_page', defaults={}, build_only=False)>, <Route('/<username:[a-zA-Z]+>/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/<username:[a-zA-Z]+>', <class 'package.pages.pages.UserPage'>, name='user_page', defaults={}, build_only=False)>>, '_name': 'user_page'}, build_only=False)>, <Route('/message', <class 'package.pages.pages.SendMessagePage'>, name='send_message', defaults={}, build_only=False)>, <Route('/message/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/message', <class 'package.pages.pages.SendMessagePage'>, name='send_message', defaults={}, build_only=False)>>, '_name': 'send_message'}, build_only=False)>, <Route('/conversations', <class 'package.pages.pages.Messages'>, name='view_messages', defaults={}, build_only=False)>, <Route('/conversations/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/conversations', <class 'package.pages.pages.Messages'>, name='view_messages', defaults={}, build_only=False)>>, '_name': 'view_messages'}, build_only=False)>, <Route('/conversation/<conversation_id>', <class 'package.pages.pages.ConversationPage'>, name='conversation', defaults={}, build_only=False)>, <Route('/conversation/<conversation_id>/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/conversation/<conversation_id>', <class 'package.pages.pages.ConversationPage'>, name='conversation', defaults={}, build_only=False)>>, '_name': 'conversation'}, build_only=False)>, <Route('/boards', <class 'package.pages.pages.Boards'>, name='view_boards', defaults={}, build_only=False)>, <Route('/boards/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/boards', <class 'package.pages.pages.Boards'>, name='view_boards', defaults={}, build_only=False)>>, '_name': 'view_boards'}, build_only=False)>, <Route('/boards/<board>', <class 'package.pages.pages.BoardPage'>, name='view_board', defaults={}, build_only=False)>, <Route('/boards/<board>/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/boards/<board>', <class 'package.pages.pages.BoardPage'>, name='view_board', defaults={}, build_only=False)>>, '_name': 'view_board'}, build_only=False)>, <Route('/boards/<board>/new_thread', <class 'package.pages.pages.NewThreadPage'>, name='new_thread', defaults={}, build_only=False)>, <Route('/boards/<board>/new_thread/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/boards/<board>/new_thread', <class 'package.pages.pages.NewThreadPage'>, name='new_thread', defaults={}, build_only=False)>>, '_name': 'new_thread'}, build_only=False)>, <Route('/notifications', <class 'package.pages.pages.Notifications'>, name='notifications', defaults={}, build_only=False)>, <Route('/notifications/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/notifications', <class 'package.pages.pages.Notifications'>, name='notifications', defaults={}, build_only=False)>>, '_name': 'notifications'}, build_only=False)>, <Route('/img/<blob_key>', <class 'package.pages.pages.DisplayImagePage'>, name='display_image', defaults={}, build_only=False)>, <Route('/img/<blob_key>/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/img/<blob_key>', <class 'package.pages.pages.DisplayImagePage'>, name='display_image', defaults={}, build_only=False)>>, '_name': 'display_image'}, build_only=False)>, <Route('/', <class 'package.pages.pages.Index'>, name='index', defaults={}, build_only=False)>, <Route('/', <class 'webapp2.RedirectHandler'>, name=None, defaults={'_uri': <bound method RedirectRoute._redirect of <Route('/', <class 'package.pages.pages.Index'>, name='index', defaults={}, build_only=False)>>, '_name': 'index'}, build_only=False)>]
INFO     2012-08-04 13:16:40,513 utils.py:14] {'index': <Route('/', <class 'package.pages.pages.Index'>, name='index', defaults={}, build_only=False)>, 'view_boards': <Route('/boards', <class 'package.pages.pages.Boards'>, name='view_boards', defaults={}, build_only=False)>, 'notifications': <Route('/notifications', <class 'package.pages.pages.Notifications'>, name='notifications', defaults={}, build_only=False)>, 'friendship': <Route('/friendship', <class 'package.pages.pages.Friendship'>, name='friendship', defaults={}, build_only=False)>, 'signup': <Route('/signup', <class 'package.pages.pages.Signup'>, name='signup', defaults={}, build_only=False)>, 'view_messages': <Route('/conversations', <class 'package.pages.pages.Messages'>, name='view_messages', defaults={}, build_only=False)>, 'conversation': <Route('/conversation/<conversation_id>', <class 'package.pages.pages.ConversationPage'>, name='conversation', defaults={}, build_only=False)>, 'send_message': <Route('/message', <class 'package.pages.pages.SendMessagePage'>, name='send_message', defaults={}, build_only=False)>, 'new_thread': <Route('/boards/<board>/new_thread', <class 'package.pages.pages.NewThreadPage'>, name='new_thread', defaults={}, build_only=False)>, 'view_board': <Route('/boards/<board>', <class 'package.pages.pages.BoardPage'>, name='view_board', defaults={}, build_only=False)>, 'display_image': <Route('/img/<blob_key>', <class 'package.pages.pages.DisplayImagePage'>, name='display_image', defaults={}, build_only=False)>, 'user_prefs': <Route('/preferences', <class 'package.pages.pages.UserPage'>, name='user_prefs', defaults={}, build_only=False)>, 'user_page': <Route('/<username:[a-zA-Z]+>', <class 'package.pages.pages.UserPage'>, name='user_page', defaults={}, build_only=False)>}
INFO     2012-08-04 13:16:40,515 __init__.py:26] /conversations
INFO     2012-08-04 13:16:40,533 dev_appserver.py:2952] "GET /conversations HTTP/1.1" 404 -
INFO     2012-08-04 13:16:40,626 dev_appserver.py:2952] "GET /favicon.ico HTTP/1.1" 200 -

我到底没有注意到什么？

【问题讨论】：

我已按要求更新了帖子。我的印象是添加主函数仅适用于使用 cgi 的较旧的非线程安全运行时。
你是对的。我试过了，它是双向的。我认为问题在于你的装饰器应该读取 application.route 而不是 app.route （app 没有在任何地方定义或者它在 packages.pages 中？），但这应该会引发错误。
哦，我在做from package.application import application as app
在调试方面您尝试过什么？您的处理程序是否按照您的预期更新路由列表？如果您在主模块末尾记录路由器的路由列表，您会看到什么？另外，您为什么要定义自定义调度程序？
自定义调度程序使我可以返回字符串而不是写入响应

标签： python google-app-engine webapp2

【解决方案1】：

我有一条路由覆盖了所有其他路由，但在它们上引发了 404（/username 导致用户页面；没有名为“对话”的用户）。我忘记在切换到装饰器路由方法时让这条路由的优先级最低。

我首先使用相同的路由方法构建了一个最小的应用程序，然后发现它在应用程序引擎上运行良好。然后我在处理程序中捕获了 HTTPNotFound 异常，并在它们发生时打印了堆栈跟踪；这清楚地表明这是我的用户页面类的 get 方法中的一行故意抛出 404，那么问题就相当明显了。

【讨论】：