Logging out of AppEngine App only

I wanted to create a logout URL in an Google AppEngine app, but unfortunately the documented method (users.create_logout_url()) logs you out of all Google services, not just the app.

Fortunately, I found this post which describes how to set cookies to log you out of the app.  Here is what I did in my app:

	class LogoutPage(webapp2.RequestHandler):
	def get(self):
	target_url = self.request.referer or '/'
	if os.environ.get('SERVER_SOFTWARE', '').startswith('Development/'):
	self.redirect(users.create_logout_url(target_url))
	return
	# On the production instance, we just remove the session cookie, because
	# redirecting users.create_logout_url(...) would log out of all Google
	# (e.g. Gmail, Google Calendar).
	#
	# It seems that AppEngine is setting the ACSID cookie for http:// ,
	# and the SACSID cookie for https:// . We just unset both below.
	cookie = Cookie.SimpleCookie()
	cookie['ACSID'] = ''
	cookie['ACSID']['expires'] = -86400 # In the past, a day ago.
	self.response.headers.add_header(*cookie.output().split(': ', 1))
	cookie = Cookie.SimpleCookie()
	cookie['SACSID'] = ''
	cookie['SACSID']['expires'] = -86400
	self.response.headers.add_header(*cookie.output().split(': ', 1))
	self.redirect(target_url)
	app = webapp2.WSGIApplication( [
	(r'/logout', LogoutPage ),
	],
	debug=True)

view raw gistfile1.py hosted with ❤ by GitHub

https://gist.github.com/anonymous/4733505 

Now, I can add a link to /logout, and the user will be logged out of the app.

Many thanks to the pts.blog!