While PHP-developing it sometimes is just too tedious to do those 'add a echo here and there, then reload and search the echoed strings on the screen'-loops. So I searched for a debugger for my favourite editor emacs. After a lengthy install procedure I finally got it running: With geben on emacs you can debug PHP (step through and evaluate expressions).

The post steps you through the installation - adding in xdebug, changing the PHP configuration, and getting and installing geben (along with other required packages).

FirePHP is a plugin for Firebug, the web development plugin for Firefox, that allows PHP scripts to talk to a Firebug panel. FirePHP installs alongside Firebug, and provides a simple PHP library to bridge the two. FirePHP provides a window of insight into your PHP applications, with a simple debugging interface that won't interfere with your page content. If you already use Firebug on PHP-powered applications, FirePHP is definitely worth a look.

The FirePHP library installs onto your server and is included, via PHP, into your application. Passing errors back is as simple as using the fb() method to send information out to the Firebug instance waiting on your browser.

I just wanted to document this somewhere but whenever I work on a CakePHP project, there's always the debug info that sits at the bottom of the page. It's big and bulky and once I'm off the default CakePHP styles, it's usually pretty ugly. I've done various stylings but I finally took a moment to implement a really simple idea: Fixed position the table and then use hover styles to toggle the visibility.

He includes the simple four style entries that can be used to tame this debugging information down into something a bit more useful (and less intrusive).

I finally got around to installing Xdebug on my development environment and have decided it is the best thing since sliced bread. Installation was a breeze and the information it provides when something has gone wrong is incredibly helpful during debugging.

He explains what the software does, how it can help you and your development - even how to get it up and running on your PHP install (seriously, it's drop dead easy...why haven't you installed it yet?). He also points to the tutorial on the Zend Developer Zone introducing the powerful tool.

The PHP Development Tools (PDT) plug-in, when installed with Eclipse Europa, gives you that ability to quickly write and debug PHP scripts and pages. PDT supports two debugging tools: XDebug and the Zend Debugger. Learn how to configure PDT for debugging PHP scripts and discover which perspectives you use when taking closer looks at your scripts.

You'll need to have a machine with PHP, Eclipse, Apache and the PHP Development Tools already installed to follow along (as well as a trial version of the Zend Studio Web Debugger). They also include the methods for setting up XDebug as the debugger.

Everyday the forums see probably hundreds of topics posted where the problem is a fairly simple error. [...] As a beginner, it can be difficult to find and solve these errors. By tackling each of these in turn, I hope to teach you some methods of finding and solving them.

They look at the different sorts of errors - syntax errors, fatal errors, warnings, notices - as well as some of the ones a bit harder to track down like database problems and logical errors.

After I recently upgraded to Zend Studio for Eclipse, I noticed one troubling feature of my setup - I couldn't debug applications with "pretty urls". [...] In this tutorial, I'll show you how to make use of that power and debug your Cake applications with Zend Studio for Eclipse.

His is a four step method of simple things to get the connection working:

• Disable all .htaccess files
• Add "index.php" to pretty URLs
• Set a breakpoint to debug
• Debug your application using /index.php/ URLs

Spectator is a XUL application, which should make it cross platform. I have tinkered a bit with XUL before, but not a full application. [...] So what can spectator do? Mind that this is a first version and I really just meant it as a proof of concept. I think I got a bit further than that, but it probably still has a few bugs. Still, with the current version, you can step through a program, set breakpoints and inspect the stack. Really all you would expect from a debugger.

You can grab the latest version from the subversion repository on the Google Code website.

Debugging a PHP application or a PHP web server requires connectivity between an IDE and a Debugger engine (a PHP module which is installed on the web server). The debug protocol defines this connection. [...] When the Eclipse Foundation approved the PHP IDE project, Zend Studio's debug protocol was opened source and was chosen to be the debug protocol of the PHP IDE project.

He goes through why they made the choice, touches a bit on the security aspect of the two debugging protocols he mentioned (DBGp and Zend Studio's) as well as their common methods for output.

While debuggers exists, there isn't much of a tradition for using them in PHP. People have largely come to rely on injecting debugging code directly into the program, for inspecting program scope.

Tools mentioned include traceers and error handlers (like XDebug), some debugging parts of the popular PHP frameworks and the set of *cachegrind tools to help you parse the output of XDebug for profiling your application.