Close your web connections too!

In an earlier post, I had talked about a Windows service I was working on.  This service periodically performs an HTTP GET request to check if a device that accepts incoming HTTP requests is still working.  It was pretty simple to perform the GET with .NET -- something I'm sure many of you have done hundreds of times before.

Everything worked fine, except that after a while, I couldn't connect to the remote device and was getting a timeout.  The other developer working on the device insisted that the device was running.  In fact, it was still sending me data from time to time.  We had a problem earlier with timeouts because a breakpoint was hit on the other device while my service was trying to send a GET request.  I was sure this was the problem again.

I stopped my service and added a few more debug statements to log to the event log.  When I restarted the service, everything worked fine -- for a while.  Then the timeouts started again.  I decided to double-check the documentation for the HttpWebResponse.  Man, was I embarassed:

You must call either the Stream.Close or the HttpWebResponse.Close method to close the response and release the connection for reuse.

Doh!  I wasn't calling the GetResponseStream method since I was just interested in the Status code (I was looking for a 200 - OK).  I didn't even think about the connection I was leaving open.

I wrapped the code in a try/finally that calls the Close method and things have been running smoothly ever since!  ;)