Hanging HTTP Connections
Gpokr was running for about 3 months before I realized that IE’s 2 connection limit per hostname and a hanging HTTP connection is a risky situation.A hanging connection is when the Ajax application makes a request for data and the server waits with an open connection until data is avaialble. When data is available it is returned immediatly simulating an instant notification from the server.
This is why gpokr seems to always be moving. Cards are dealth, bets are placed, and chat happens seemingly instantly.
It seems like a hack but there are not many options to out there that give Ajax applications the ability to receive data asynchronously from the server. Yes asynchronous is part of the Ajax achronym but this is just asynchronously getting data from the server. For an event driven application like poker the client needs to get data only when it is available. Of course it could check the server every few seconds but this can be a massive overhead. A hanging connection lets the client idle until there is something to do.
The problem is that it takes up a connection. I’m ok with this on the server but the browser limits 2 connections per hostname. Thats one to hang for events, and another to send a chat message, but what if a picture needs to be downloaded at the same time. It needs to wait. Or, in the case with gpokr, what if one connection is hanging for events, the other is downloading a large image, and you only have three seconds left to make a call on pocket Aces or you’ll be folded by the server. The server folds you and you get very mad.
It doesn’t seem like this issue is talked about much within Ajax development circles. Although I ran into this article that measures the use of multiple hostnames to improve performance of a web page - essentially making more connections available to load the page in parallel.
Now, for gpokr, I use one hostname for hanging calls and another for HTTP objects so that the hanging call never slows down the sites action.
