I ran across this a reference to Fiddler a couple of days ago and I downloaded it, but hadn't had a chance to install it and evaluate it. I just figured I'd play around with it the next time I needed an HTTP proxy/monitor. Well, this morning I finally had a need for one.
This morning a friend of mine pinged me over IM having a problem using cfform to generate a Flash-based form that was talking w/a CFC. He had a simple example that was working, but when plugged into the live content it wasn't.
Anyway, a quick look w/the Firefox Live HTTP Headers extension told me that his Flash form wasn't seeing his CFC. Easy enough fix—or so I thought. After changing the path to the CFC it still wasn't working, although I could tell the Flash form was now seeing the CFC because I could see the 200/OK responses. However, I couldn't actually see what data was coming back from the server.
That when I remembered I downloaded Fiddler a couple of days ago. I figure this was as good a time to check out the application as any, since I needed an HTTP proxy/monitor that I would be able to view all of the HTTP packet data.
Overall, I'm really impressed with Fiddler. It was easy to install and get up in running. Actually, to get it working w/IE you just need to install the application—it'll automatically handle directing traffic to the Fiddler proxy when Fiddler's running. To get it running in another application, just follow the Configuring Clients documentation. I like the fact that they have an autoconfigure script that will use Fiddler when it's in memory, otherwise your application will work as normal.
If you're looking for a powerful (and free I might add) HTTP proxy/monitor, do yourself a favor and check out Fiddler. It runs on Windows 2K and above and requires the .NET framework to be installed.