Recently, I stumbled across another cause: disallowed characters in a POST array. In my case, I had single-quotes as part of the variable name. My fingers mixed up PHP array syntax and HTML form syntax.

<!-- will cause the error -->
<input type="text" name="fieldname['foo']" value=""> 

<!-- won't cause the error. besides, this is the proper syntax. -->
<input type="text" name="fieldname[foo]" value="">

kalodont points out this can also happen when using accented characters, such as ó or ñ as keys in your array.

Lately, the day job has had me busting booty on a Flash/ActionScript project that makes considerable use of the ExternalInterface class.

ExternalInterface allows Flash to communicate with its HTML container using JavaScript. It’s a groovy feature, but one that changes the development process a bit. Unlike straight-up Flash development, ExternalInterface requires you to test interaction between the movie and its container.

One way to do this is using the Firebug console. Set up a simple debug function embedded in your HTML or in an external JavaScript file: function debug(data){ console.log(data); }. Then pass troubleshooting data to it using ExternalInterface.call('debug','data you want to write'); just as you would with trace().

I even used this technique to dump XML data to the console. Works amazingly well.

A minor drawback: compiler errors won’t be written to the console. Instead you will see a generic error message, and your movie won’t load.

Using Flash Tracer

For a more robust option, try Flash Tracer, a Firefox extension by Alessandro Crugnola. Flash Tracer uses native Flash logging to deliver trace() messages directly to the browser. To use it, you’ll need to install a debug version of the Flash Player.

Using LiveHTTPHeaders

Sometimes when sending and receiving data to and from a server, you can’t tell what’s wrong by looking at your Flash application. There could be an error in your server side code. Or perhaps there’s a problem with the data you’re sending. This is where LiveHTTPHeaders comes in handy.

LiveHTTPHeaders shows both browser-and-Flash request headers and server response headers. It also sends encoded GET and POST data from HTML forms or ActionScript URLRequest() / URLVariables() / URLLoader() operations.

This extension won’t show the actual data the server has returned. But you can use it to spot things like invisible line break characters and internal server errors.

Related posts:

• Essential Firefox Extensions
• My new favorite Firefox extensions
• Clearing LoadVars() in ActionScript
• OurIndustryIsBroken.com: Tracking site users and traffic with PHP, MySQL and ActionScript

The goal of frameworks — be they server side, JavaScript-based, or CSS-based — is to decrease development time. With server-side frameworks, I also find that they force some organization and structure to my code that it might not otherwise have. But every framework has a learning curve.

They also come with a performance cost. More code means more processing time and/or effort, longer download times and — this is particularly important when talking about client-side code for mobile devices — more energy consumption.

There’s a trade off with frameworks, then, between development ease and optimized code.

I personally think CSS frameworks are overkill. Even using a reset style sheet is often more code than necessary. With JavaScript frameworks, my opinion is more balanced. JavaScript frameworks are wonderful for quickly creating animated effects. But if the task is just to toggle the visibility of an element or clear a search box, surely, custom code is the lighter weight option.

The one area where I am most in favor of using frameworks is application development. Applications have a lot of little pieces to worry about. I kind of like the reassurances that frameworks offer. That said, I agree with Rasmus Lerdorf that a good framework should be lightweight and speedy (his favorite, if you can call it that, is CodeIgniter).

But what about you? How do you decide whether to develop something yourself or use a framework / library? Do you prefer frameworks for developing server-side applications? What about for client-side development? When, where, and why do you use frameworks?

It’s a lightweight interactive piece for the back-to-school season. Users plot their dot on the graph and see how they compare to other users who’ve answered the same graph. You can click a white dot to see what graphs a particular user has answered. If you’re revisiting a graph you have already answered (as remembered by Flash’s SharedObjects and cookies), the graph will auto-load everyone’s dots.

Of course it comes with the usual groovy bits: tags, browse, and search. You can also highlight a friend (assuming they have answered the same graph), or email it to a friend.

This was a serious collaborative effort involving ActionScript, PHP, JavaScript, and MySQL development. Stefán Kjartansson, Kevin Byrd, and one of our summer wonder interns Ted Ullrich did the design and visual effects. Nate Steiner created the HTML and CSS.

My role? Handle the back-end development and make it work with the Flash and ActionScript 2-driven front-end. I also did some additional ActionScript development to properly process and load the XML data.

I used CodeIgniter to power the back end, along with some custom PHP scripting to support URLs with query strings (for tracking purposes). In CodeIgniter, query strings are an all-or-nothing proposition. As a result, I wound up re-writing the home page code, but retaining most of the CodeIgniter views used throughout the site. This way the site is still easy to update and change.

We’re still tweaking and enhancing it, but we’re very happy with how it’s working so far and how many users are responding to it.

The concept

“Meet me in the future …″ Students (ideally) complete the sentence “I will be …” Answers have ranged from inspiring to offensive (which have been deleted), but the response has been good, in our opinion. And at least one student called it “inspiring.”

The technology

SATAchieveMore.com integrates a Flash / ActionScript 2.0 front end with a PHP+MySQL-driven back end. I did the bulk of the ActionScript development, and worked with our motion graphics developer to integrate the motion effects. I used the CodeIgniter framework to develop a middle layer that does the communication between the database and the SWF. I also used CodeIgniter to develop an administrative tool (to manage submissions) for the client.

Why CodeIgniter?

I chose CodeIgniter because it’s extraordinarily easy to configure and learn, and it’s well-documented. Aside from one day lost to some excess whitespace, developing with CI was easy and painless.

Related posts

• Clearing LoadVars() in ActionScript
• Debugging tip: “Disallowed Key Character” error in CodeIgniter
• What’s your favorite PHP framework?

The line feed (LF) and carriage return (CR) characters (and their hex code equivalents (%0D and %0A) are forbidden in CodeIgniter’s framework. The hard part is tracking down exactly where that extra line break character lives.

In my case, there was an extra line of blank, barren, not-all-that-obvious white space at the very, very end of one of my controller files, just after the closing ?>.

Related:

• PHP header error messages
• Four common P H P errors and what they mean

Related post elsewhere: You may be interested in PHP frameworks – Which one is Most Suitable for you?

So I’m making my first foray into PHP frameworks. I’m tinkering with CodeIgniter right now. I chose it on a lark, in part because it was easy to install, didnt’t require too much tinkering with configuration settings, and well-documented.

Though I like CodeIgniter’s OO-MVC approach, I’m not wedded to it. I’m also very interested in what else is out there. So please share with us:

• What PHP framework are you using?
• What’s your favorite PHP framework (if you have tried enough to compare)?
• If you were going to recommend a framework to learn, which would you choose (or warn folks to avoid) and why?

And if you haven’t yet looked into PHP frameworks, here’s a (far from comprehensive) list to get you started:

• Akelos
• Biscuit
• Blueshoes
• CakePHP
• CodeIgniter
• Easy PHP Framework
• Fuel PHP
• Limb PHP Framework
• Lithium
• P4A
• PHOCOA
• PHP on TRAX
• Prado PHP Framework
• Propel
• Qcodo
• Qcubed (a fork of Qcodo)
• Seagull
• Simplicity
• Smarty (Although it’s a bit more of a templating framework)
• Solar
• Sourdough
• Stratos
• Symfony
• Vork
• WASP
• Web Application Component Toolkit
• Yii
• Zend
• Zoop

Also worth reading, Rasmus Lerdorf’s February 2006 post, The no-framework PHP MVC framework.