Home of the Spider

Coldfusion CFC Local Variables

I'm embarrassed to admit that I haven't done much development with CFC's. Considering my background as a Java developer, there really is no excuse.

So I'm trying to make up for lost time. Almost all the development I'm doing these days involves CFC's. Many times I'm moving existing code in to new CFC's, but the benefits are great. Its the single most important feature in the language.

Of course, my CFC honeymoon came to a crash ending. I have a component that certain information on each link on the site. The data is stored in a database, but because there are many lookups for each page rendered, I didn't want to do a database lookup. Instead, I created a component that stores the data in a struct, keyed on the URL. The component is stored in the Application scope, so the data is pulled once, and the lookup happens in the component.

Each element in the struct is actually another struct with a bunch of information regarding that link. The function urlLookup first initializes the return variable called "info"

<cfset info = "">

then does the lookup

<cfif structKeyExists(urls, key)>
    <cfset info = urls["#key#"]>
    <cfset info.foundResult = true> <!--- flag this as a valid result --->
</cfif>

because I'm expecting a struct from this function, if no URL was found, I create a struct and set the foundResult to false

<cfif info is "">
    <cfset info = StructNew()>
    <cfset info.foundResult = false>
</cfif>

then return info

<cfreturn info>

Mysteriously, I kept getting errors "Element FOUNDRESULT is undefined in URLS". Can you spot the error? Remember, this object is in the application scope, so many requests are hitting it at once.

The problem is in this line

<cfset info = "">

the variable "info" is a global variable, not local to the function. If a second request enters the function before a previous request finishes, it re-initializes the global variable "info," which is then returned. FOUNDRESULT will not be found because the variable is an empty string!

The solution is a to add a little keyword "var," so the line of code looks like this

<cfset var info = "">

this makes the variable local to the function, so each call to the function creates a new variable local to that call. It is recommended that all variables, including query names, be initialized with the var keyword (referred to as "varing" your variables.) 

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Item of the Day: KWC Domo 10.061.033 - Kitchen Faucet from KWC

Generating CSS for Firefox

There are many reasons why you want to keep the CSS in a separate file. The benefits are clear, easier to manage, easier to apply to multiple pages, cacheable, etc.

Recently, we redid our Hansgrohe page. See the left side column with all the categories? The width of that column changes depending on whether you're viewing the main Hansgrohe page, or a category page. Because the style is exactly the same and the only difference is the width, I didn't want to create another stylesheet just for the category page.

Instead, I made the CSS page a ColdFusion page, and I pass along a flag to indicate what the width should be. There is one <cfif> tag looking at that flag and setting the appropriate width. The resulting CSS is the exact same, just the URL now ends in ".cfm" instead of ".css".

In IE, everything is wonderful. It parses the file and applies the styles. In FireFox, not so good. No good at all. It refuses to look at the file as a stylesheet.

The solution is to tell FireFox that it's a CSS file. You do this by adding this line of code:

<cfcontent  type="text/css" >

Thats all. You can translate that line to the language of your choice.

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Item of the Day: Iperbole Monoblock 5131.101 - Bathroom Faucets by Porcher

Coldfusion CFC in Sub-folders

Its one of those little things that can make the all the difference.

I manage a bunch of websites. By far the most confusing one is the one that has all the files stored in the root folder. Why is this so confusing? Because you cannot gain any understanding of the relationship between the files just by looking at the files and directory structure.

A properly structured directory structure can tell me so much about the files without reading them. I can guess what a file in "webroot/shopping-cart/google-checkout/callback" should do, even without opening the file. Finding and fixing bugs is so much easier in a properly structured directory.

As I began doing more and more of my new development in CFC's, this issue bothered me. I know how to instanciate an CFC in the root folder. Say you have a CFC "shoppingCart.cfc" in the root, you instanciate it like this: <cfset cart = CreateObject("component", "shoppingCart")>. But I didn't know how to instanciate a CFC in sub-folders.

As it turns out, its quite simple (that seems to be a ColdFusion mantra.) Say our shopping cart CFC is located in "webroot/siteComponents/cart/shoppingCart.cfc". To instanciate, you do this:
<cfset cart = CreateObject("component", "siteComponents.cart.shoppingCart")>

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Item of the Day: Blancodiamond 511-708 - Silgranit Kitchen Sink by Blanco

Hansgrohe Showers & Faucets

I always enjoyed a little bit of design. Being a programmer, design work stimulates a different part of my brain, one that I dont use on a daily basis. However, professional web design takes experience and practice and I had neither, so my meager design skills were relegated to my own websites. I'll show you 2, so you understand what I'm talking about:

1. MP3 Shiur: www.mp3shiur.com
2. XDS Tech: www.xdstech.com

As I said, not too impressive.

Luckily for me, I managed to convince my boss to let me try my hand at designing a page for Hansgrohe, a high-end faucet and shower company. Our standard brand page is pretty boring, so we wanted something more engaging.

This is our new Hansgrohe page. 

I like to think that I was successful. Not that I think its the webs most beautiful page, but its a pleasant engaging page. Have any ideas on how I can improve the page? Let me know in the comments.

But the real question is, does it sell?

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Item of the Day: Hansgrohe Axor Starck 10111 by Hansgrohe - Designed by Axor Starck