PHP developers working on Debian have one more reason to be happy with their choice of linux distributions - as Derick Reathans notes, XDebug has been added as an apt-getable package to the Debian systems.

Since a few days, there is a new package in Debian: php5-xdebug. After a few years of talking licenses, due to the help of Martin Meredith and Francois Marier Xdebug can finally be installed with apt-get.

XDebug is a debugging and profiling tool that adds additional information (more than just the usual "error on line..." sort of thing) to the output of your PHP scripts. It also adds more complex functionality like profiling and code coverage reports run on your applications.

In a new blog entry today, David Coallier has posted about two new offerings that are in the works for a web-based frontend to XDebug:

For quite a while in the PHP Community (And even myself) I have heard people asking about either an online tool to work on cachegrind output files or a cross platform tool that would have the ability to do what KCacheGrind does on Linux but for Windows and OSX.

He mentions the origin of the idea for a cachegrind app as a part of the Google Summer of Code (that did get accepted and will be worked on by Chung-Yang Lee). The other, Webgrind is an independent project from the other but looks equally as promising.

Check out Vinu Thomas' thoughts on the matter too.

Joakim passed along a note today about a new web-based frontend for XDebug:

My about page has mentioned a web based frontend for Xdebug for some time. The project has a name now: The idea for Webgrind, a spin on Valgrind, came from lack of profiling tools for PHP, particularly on OSX. Though it is possible to install kcachegrind on osx it seems overkill for many uses and is definitely not as easy as unzipping a folder to the webroot.

He and Jacob Oettinger have started up the project and have posted some initial code over on the Google Code page for Webgrind. You can check out a screenshot of it in action here too.

The main PHP.net website has posted a list of people participating in this year's Google Summer of Code project on various PHP projects. These include:

• PHP Optimizer by Samuel Graham Kelly IV, mentored by Derick Rethans
• gsoc:2008 - XDebug by Chung-Yang Lee, mentored by David Coallier
• PHP Bindings for Cairo by Akshat Gupta, mentored by Anant Narayanan
• Implement Unicode into PHP 6 by Henrique do Nascimento Angelo, mentored by Scott MacVicar

You can check out more information on the projects (including links to their individual pages) on this page of the Google Code website.

Andreas Gohr has a new blog post today that talks about a way to really get to know your code better - use XDebug to see it from the inside out.

Xdebug is a PHP extension which helps you to understand, debug and profile PHP. It can help you to find bottlenecks or give you an quick overview what happens in code you aren't familiar with, yet.

The post gives a brief overview of the installation of the extension (building a shared module) and shows how to get started with profiling an application. He talks about the cachegrind tool you can use to parse the results and the kcachegrind app that will make the results a bit more visual.

As a bonus, he also throws in a bit about function tracing - picking out each small bit of functionality in the code (the function/methods) and gathering stats for each.

Gennady Feldman, in light of some of the recent talk about enhancing the performance of your PHP applications, has written up this new post comparing two of the more favored software packages - APC and Eaccelerator.

Some websites use other technologies like Java and face the exact same problems. There are different variables involved here and the most common one is database. So I thought i would post a couple of articles related to performance and tuning.

This this post of the series focuses on the first of the two - APC - and talks about places it's used and includes some general performance recommendations. These include "Don't try to throw everything at your poor database" and the importance of XDebug.

For anyone that's had an issue with getting XDebug to work with the Debian linux distribution, you might want to check out this helpful hint Carsten Lucke has posted about.

This week I started to setup a Debian-based (Etch) web-server with PHP 5.2 in a virtual-machine with VMWare. Part of this setup was getting XDebug2 integrated. It's really awesome and my students definitely need to learn about it. [...] Building went well as usual but when I tried to integrate the extension inside php.ini it was all weird.

His system kept throwing him an error when he tried to load the shared module using the zend_extension directive, hand things happened. Loading it normally worked (so he knew it wasn't the module) and he finally figured out the problem:

But I need to enable it as Zend extension. Whatever. I finally used the full path to xdebug.so to load it [...] that worked.

Arnold Daniels has a suggestion for developers out there to help improve the performance of their applications - check your loops.

So you have a script which is not performing the way you want to. The first thing you should do it try to find out what the problem is. There are some tools out there that can help you.

He mentions the profiler in Zend Studio as well as the one in XDebug. If you can't install those, however, he has another suggestion - FirePHP (a tool that can help time execution times in a simple and easy to include way.

With tools in hand, he offers a few suggestions as to what to check for and do in your applications:

• Get the data ready before going into the loop
• Don't do things in the loop, you can also do outside it
• Use create_function to aid you
• Be careful with abstraction in loops
• Sometimes you can prevent loops altogether
• Last resort: write an extension

Pierre-Alain Joye has posted an example of one way to use the XDebug software - to debug the symfony framework or any other script (with the help of vim).

Xdebug is one of the best debugger and profiler for php (maybe the only good one in open source :). The only problem is its lack of dedicated client. The only problem is its lack of dedicated client, however there is many plugins for many IDE or editors like Eclipse PDT or weaverslave and even for my favourite editor, Vim.

He quickyl runs through the installation of XDebug in your installation and the script needed to set up the debugging in vim. All that's left is to add the "XDEBUG_SESSION_START=1" flag to the end of your script name and letting the information flow in.

The Zend Developer Zone has posted the fifth and final installment of the series Stefan Priebsch has written up about debugging your application via the XDebug software.

Today, we will have a look at another great feature of xdebug - creating code coverage statistics. Code coverage statistics show how many times each line of the code has been executed. Conversely, they also show which lines of code have not been executed, which is in fact much more interesting.

He talks a bit about what code coverage is and how it can help you fine tune your application. He walks you through the installation of the two packages that will help out with running the reports - phing and PHPUnit. Using these, he shows how to create a simple unit test and a build file for phing that combine and, via the XDebug calls to xdebug_start_code_coverage, xdebug_stop_code_coverage and xdebug_get_code_coverage, are used to generate the output graphs and stats in a nice, easy to read interface.