Channel API closes a channel - google-app-engine

Question

First off, thank you #Moishe for the very useful API. I'm having a little timeout problem, maybe someone knows the answer. Here's how I open the channel:
var openChannel = function () {
var channel = new goog.appengine.Channel($('#token').val());
var socket = channel.open();
socket.onopen = function () {};
socket.onmessage = function (m) {
var message = JSON.parse(m.data);
// do stuff
};
socket.onerror = function (error) { alert(error); };
socket.onclose = openChannel;
};
openChannel();
This works fine, I post my messages and they go to the other clients pretty quickly. But if I stay on the page for roughly 15 minutes, the server loses track of my channel. In dev, it throws an error (which I saw was a known bug: http://www.mail-archive.com/google-appengine#googlegroups.com/msg44609.html). But in prod, it still ignores messages on that channel after about 15 minutes.
We fixed it by adding a setInterval(getSomeUrl, everyMinute) to the page, but we'd rather not have to do that. I noticed in Moishe's last commit for the trivia game sample that he took out a keep-alive. I didn't understand how he replaced it, and what he meant by onopen is reliable:
http://code.google.com/p/trivia-quiz/source/browse/trunk/src/index.html
Update: Server side code is
class Home(BaseHandler):
def get(self):
self.checkUser()
if self.user:
userId = self.user.user_id()
token = channel.create_channel(userId)
chatClients[userId] = token
self.model['token'] = token
players = self.checkChatRoom()
self.model['users'] = players
self.model['messages'] = map(lambda k:db.get(k), self.chat_room.messages) # TODO: Replace this line and the next with a query
self.model['messages'] = sorted(self.model['messages'], key=lambda m: m.timestamp, reverse=True)
self.writeTemplate('index.html')
BaseHandler is just a base class I use for all my GAE handlers, it provides checkUser which redirects if the user isn't logged in, and it provides writeTemplate which takes what's in self.model and writes it in a template. It's just a proof of concept, so no cache or anything else other than what's above.