Idle Musings of a Delphi Junkie

I was reminded once again this week of the usefulness of a tool I initially discovered a while ago when resolving a bug with CodeCentral downloading submissions in IE7. This handy little utility called Fiddler is an HTTP proxy which allows you to intercept and log all HTTP traffic between clients and servers. It also allows you to place breakpoints so request and response packets can be manually altered.

This week I've been working on developing a REST web service client. I can't make the assumption that a timed out transmission wasn't actually received and processed at the server, so I needed to ensure I gracefully handled any timeouts when posting requests. The thing that made simulating this particular condition interesting was that I wanted certain requests to succeed and others to fail. And because I don't have control over the server, this would normally require writing my own dummy server or proxy app so I could simulate this behavior. But by using Fiddler, I was able easily to intercept all traffic to the server and prevent certain packets from getting through, which would then have the desired effect of a timeout being raised for those particular HTTP post operations.

While this may be vastly under utilizing the power of Fiddler, it certainly served as a timely reminder to me how useful this tool is when developing HTTP based applications.