FusionDebug is an easy straightforward tool, but if you leverage the experience of others, you can be even more productive.

Elsewhere in this issue, Jeff Houser introduces the FusionDebug interactive step debugger. I'd like to carry that discussion a bit farther and share various tips, tricks, and traps I've learned from my experience with the tool and that I've gleaned from available FusionDebug resources. I've been using FusionDebug (FD) for a couple of months now and am a fan.

First I'd like to share some general tips that address some common questions or concerns I've observed, broken down into tips on installation and general use. These should help you appreciate the tool's use and how to make the most of its available features.

Then I'd like to share some tricks or features that you may not readily notice that will make the tool still more useful. Finally, I'll share some traps or problems that you may encounter and how to resolve them.

Tips on Getting Started
Why Bother Using a Debugger?
Perhaps the first and most important tip to share is my perspective on why I think FusionDebug is an important tool. I realize that there are some who dismiss it or may simply feel that there's nothing it can do that CFDUMP or CFOUTPUT can't. I disagree and have addressed those concerns in the first two entries in a series in my blog at http://carehart.org/blog/client/index.cfm/fusiondebug.

What If You Have Problems Using or Installing the Tool?
If you have problems using or installing it, you'll find that FusionDebug support is great. The folks at Intergral, who also make FusionReactor, offer free support for the tool at support@fusion-reactor.com.

How Do You Learn About Using and Installing the Tool?
The vendor's site, at www.fusiondebug.com, offers several very useful resources, including a well-done User Guide and Captivate videos showing how to use the tool, all online and free. There are also ample support FAQs and articles on the site to help solve common installation and troubleshooting glitches.

"I Really Don't Want to Switch to Eclipse"
Here's really good news: you don't have to switch to Eclipse. Yes, the tool does run atop Eclipse, as Jeff explains, but you don't have to give up your favorite CFML editor, whether it's Dreamweaver, HomeSite+, or something else. Use those for editing, and fire up Eclipse (and FD) when you debug.

And you don't necessarily have to install Eclipse, as you may already have it installed. Are you using FlexBuilder? That, too, is an implementation of a commercial plug-in atop Eclipse. You could add FD to that. If you do, when you're debugging Flex apps the tool will switch "perspectives" when control passes from the Flex app to the CFML page it calls.

"I Don't Want to Risk Hurting My Current Eclipse Implementation"
On the other hand, you may want to think twice about installing FusionDebug on top of FlexBuilder or even the CFEclipse-based implementation of Eclipse you may have. If you have any concerns about one plug-in hurting another, remember, you can install more than one copy of Eclipse. When you download it from Eclipse.org, it's just a zip full of files that you extract to a directory. It's okay to install it more than once in a different directory.

Along the same lines, another reason not to install FD atop a FlexBuilder install is if you're running the FlexBuilder trial. When it expires, you'll no longer be able to open that version of Eclipse.

Tips on General Use
Does It Just Debug CFM Pages? I'd Like to Debug CFCs and Calls from Flex, AJAX, Web Services, and Such
Great news: it not only debugs CFM pages but CFCs as well. Regardless of whether you instantiate the CFC in CFML or invoke it via Flex, AJAX, Web Services, Flash or Flash Remoting, or CFMX 7's gateways, FusionDebug will intercept the request.

More than that, the tool is savvy enough to recognize that there are special variables inside a CFC or method, and it will show the var (function local scope) and the "this" scopes in the "variables" pane.

Further, when debugging in a CFC method, there will be additional information in the "stack trace" pane. This is the pane (top left as typically configured in FusionDebug) that shows the filename and line number of the line where control has stopped. When control is stopped in a CFC method, this will also show the function name for the method.

Can It Debug CFSCRIPT Code?
Again, for some reason, many seem to have low expectations for the tool and often ask if it can debug code in CFSCRIPT. It absolutely can.

What Does "Step Into" Mean?
"Step into", when used on a line that would go into a new  file such as a CFC method, CFINCLUDE, or custom tag, will open that new file and show the first line of CFML code in that file.

What Does the User See While a Page Is Being Debugged?
When a browser requests a page that's being debugged and has stopped at a breakpoint, it will appear to be hung until the code sends output.

I Want to Be Able to See the Output Being Generated During Debugging
Following on to the previous tip, you may not see the output being sent to the browser while in the midst of processing breakpoints because ColdFusion buffers output until the page completes or the page buffer fills, or a CFFLUSH tag is executed. While it would be nice if the tool offered a pane to see the output as it's being generated, you have a couple of other options if you really want to see the output during debugging. You could insert CFFLUSH tags periodically in the page, or use the available CFFLUSH INTERVAL attribute to cause flushing after a certain number of bytes. Just be aware that, as explained in the CF docs, the browser may not display partial-page output if enough data hasn't been sent or until certain tags are closed (e.g., images, tables, and frames).