Saturday, March 20, 2010

HTTP Connections revisited

In a previous post entitled, HTTP connection reuse in android, I tossed out a code snippet for an HttpClientFactory that would spit out a DefaulHttpClient implementation suitably configured for re-using already open HTTP connections to serve multiple requests across multiple threads.

My hasty implementation from that post leaves a few things to be desired. Primarily, it's a singleton implementation which can lead to some problems. Since it's effectively a global resource, doing things like modifying the time out value, or forcibly closing the connection manager (as one commenter pointed out), could lead to the HttpClient to be in an invalid or undesired state when reused at a different time or a different part of your application.

So here's a simplified version without the singleton garbage:


The ideal place to use something like this is when you want to download multiple items from a single remote source, for example, if I needed to download a bunch of thumbnails to be displayed in a ListView, I could have a thread pool downloading images concurrently and all sharing this one HttpClient instance, reusing HTTP connections as they became available (all managed inside the HttpClient)