Kevin A. Schmidt

Now that some of the hype surrounding ColdFusion 5 has begun to die down, you may find yourself ready to tackle one of its new features - user-defined functions. User-defined functions (we'll call them UDFs) are one of the most talked about features of ColdFusion 5 and certainly one of its best. UDFs are powerful, yet simple to create. They're also fast and highly flexible. (For more detailed information about UDFs, check out the article by Raymond Camden in this issue of CFDJ.) In the meantime, let's create our own. Replacing Custom Tags Last April I wrote an article focusing on the creation of a custom tag to calculate a mortgage payment (CFDJ, Vol. 3, issue 4). Now it's time to turn that custom tag into a UDF. This is an ideal condition for a UDF, because we're performing a simple calculation on several values that are passed in and the UDF is able to do this muc... (more)

Debugging: Tips and Tricks for Detecting Errors

Imagine, for a moment, a world in which we all wrote perfect code - a world in which we'd never have to spend precious time debugging our applications. Okay, your moment's up. The world is, of course, far from perfect, and the reality is that we spend a fair amount of our time trying to chase down ColdFusion errors. After several hours of staring at the same lines of code, it's easy to become frustrated - especially if there's a deadline looming, or worse, a boss peering over your shoulder asking, "Is it ready yet? Can I demo it?" My goal, then, is to keep you from throwing your ... (more)

PDFs on the Fly

If you've ever generated any type of custom report using ColdFusion, odds are you've fielded this question at some point in time. And while the task may sound rather difficult, it can be made relatively simple with a particular open-source third-party tool. HTMLDOC The tool, offered by Easy Software Products (www.easysw.com), is called HTMLDOC. The company has made this tool available through the GNU General Public License, so you can download and use it for free. Among the many things HTMLDOC allows you to do is convert an HTML file to a PDF. HTMLDOC is a normal Windows applica... (more)

The Question: What's FTP?

When I told them there was a better way to send us large files. They'd been accustomed to sending large image files via an e-mail attachment; I wanted to get them away from this practice and suggested that they use FTP (file transfer protocol). That's where I hit the roadblock. Many of our clients only knew how to send e-mail, surf the Web or create a document in Microsoft Word. So rather than spend several hours trying to teach each of them how to use an FTP program, I turned to ColdFusion for a quick and easy solution. With ColdFusion I could create a simple and easy-to-unders... (more)

Setting Up Shop: Adding a Cart with ColdFusion

Ever wonder what's going on behind the scenes when you click that "Add to Cart" button on your favorite Web site? Sure, whatever you want to buy gets dropped in your cart, but what actually makes it work? There are actually several answers here, so let's go step-by-step through the principles of designing and developing a simple shopping cart system with ColdFusion. The Shopping Cart Say you're ready to sell on the Web and you want people to be able to use that handy little button "Add to Cart" to purchase your items. To do this, you need a shopping cart, and what, exactly, does t... (more)