A GAEO notebook

def get_method_only(fn):
    def wrapper(self, *args, **kwargs):
        if self._request_method.upper() == "GET":
            return fn(self, *args, **kwargs)
        else:
            self.hnd.error(405)
            self.render(text="405 Not Allowed")
    return wrapper

@get_method_only
def show(self):
    self.render(text="Thank you for your GET request!")

How do I protect my top secret controller-action from being requested anonymously? I use a decorator! Although the syntax is more complex to understand than common code in Python, the result is very handy. Now I have to simply decorate my secret actions by adding "@login_required". If anonymous users request /secrets/confidential now, they get redirected to the login page and back after login.

from gaeo.controller import BaseController
from google.appengine.api import users

class SecretsController(BaseController):

    def login_required(fn):
        def wrapper(self, *args, **kwargs):
            if users.get_current_user():
                return fn(self, *args, **kwargs)
            elif self and issubclass(self.__class__, BaseController):
                self.redirect(users.create_login_url(self.request.path))
        return wrapper

    @login_required
    def confidential(self):
        self.render("Thank god you're a user!")

In your controllers, that are instances of BaseController, you can override the "before_action" and "after_action" methods that get called right before/after the requested action. A common use case is checking some preconditions within the before_action preventing the action from being called if it fails. At the time of writing (release 0.2 beta) you can't do that. But I commited some some today that enables it: In case your before_action returns False, both the action and after_action will not get called.