NSURLConnection ignores Keep-Alive timeout?

Question

I'm converting my app to use HTTPS and would like to avoid the handshake cost as much as possible by keeping open a long-lived connection.

From reading the web and other answers on stack overflow it appears NSURLConnection should transparently keep the underlying socket open if the server responds with Connection: keep-alive and Keep-Alive: timeout=N.

However I am seeing that my connections are only kept open for around 10 seconds. My Keep-Alive response is set to much more than this. I am also sending Connection: keep-alive in my request headers.

Can anyone shed some light on this? I really don't want to have to use CFNetwork to achieve this.

Answer 1

You have two ways:

As Tyler states in his answer here:

You can specify a timeout in your NSURLRequest object. One way to do this is to construct it via the requestWithURL:cachePolicy:timeoutInterval: method. (You can pass in the default NSURLRequestUseProtocolCachePolicy cachePolicy parameter if you don't want to worry about that part.) The timeout is a floating-point value in seconds, as are basically all time intervals in the iPhone SDK.

Also make sure your NSURLConnection's delegate is set and responds to the connection:didFailWithError: method. A connection always calls either this method or connectionDidFinishLoading: upon connection completion.

Or do what Kris suggests in his answer here:

ASIHTTPRequest has an expirePersistentConnections method. It may do what you're looking for.

It's not a drop-in replacement for NSURLConnection, but it's not too hard to port code from NSURLConnection to ASIHTTPRequest.