Channel API channel gets disconnected without onclose or onerror calls. JavaScript console has logs of failed HTTP calls to talkgadget.google.com

Question

I have implemented Google App Engine's Channel API feature in my application. Everything runs smoothly. I create new channels every one hour for every user. I have managed to maintain one channel per session (same channel for different tabs in a browser). I have implemented the onerror and onclose methods in such a way that every time they are invoked, a call is made to the server requesting for a valid token.

Sometimes, after the channel's been alive for a while, it gets disconnected. I can see failed HTTP calls to talkgadget.google.com on the JavaScript console. The URLs are something like this:

https://129.talkgadget.google.com/talkgadget/dch/bind?VER=8&clid=.....

These calls have responses like "401 (Token timed out)" or "401 (Token invalid)". Which is indeed true, the token used by the client is invalid. It should get updated with the new token but the onerror or onclose methods aren't invoked. How am I supposed to figure out when this would happen or how to handle it? There is no real way to say if a client is disconnected or not except for the onerror or onclose methods. This issue is resolved if I refresh the page (I get the valid token from database every time the user refreshes).

I checked the socket objects's "readyState" property and it had the value 1. There are many who face this issue and as of date, there seems to be no valid solution offered by the folks at GAE.

Edit: I'm a premium account holder and this issue is holding back our deployments.

Edit 2: Having one channel per tab reduces the frequency of this happening. But it doesn't solve the problem completely.

Moguel

This is an awesome question! It just needs an amazing answer from a Google App Engine engineer. – Komara

Answer 1

It has been six days since I posted the question and there has been no response from the AppEngine team or any other users.

The workaround I applied was to have a button on the site that would fetch the (valid) token from the database, close the channel and then open it again with the token received. Sometimes its a new token which should've been received before, sometimes its the same token that had been valid all along.

This issue cannot be replicated often I agree, but when it happens, it causes a lot of damage. I hope I find a solution soon.

Edit: Having one channel per tab reduces the frequency of this happening. But it doesn't solve the problem completely.

Moguel