Getting The Bugs Out of PHP Web Applications

With PHP application development, the process of debugging an app is often as difficult as the creation of the app itself. By using the correct tools, you can debug the app properly, with no suprises when it goes live.

The difficulty of debugging PHP applications arises for several reasons, including the different technologies used to create the PHP app itself. Most PHP applications utilize PHP, of course, along with HTML, JavaScript, CSS and SQL, hence part of the application runs in the browser, while other parts of the application run on the server. Its “life” includes HTTP requests and responses, with residual information being retained in cookies and hidden form fields. None of this contributes to the use of a solitary debugging mechanism for PHP applications.

The way to get around the limitations of PHP is through the use of specialized debugging tools for each task. For PHP itself, a debugger extension does all the work. Xdebug is a free PHP debugger that works for both Windows and Linux versions of PHP, along with practically any web server. It has all the features that are needed, including stack traces, breakpoints, etc. and utilizes functions that are called from within the PHP application itself. It also has the ability to be used to track HTTP sessions through the use of parameters, which allows the developer to debug the application through multiple HTTP sessions.

A Firefox plug-in called Firebug can be used for HTML and JavaScript, and it runs in the browser while you use the PHP application in the browser. SQL debugging requires a different approach, with the SQL query being executed through the SQL management console.

Some Integrated Development Environments (IDEs) provide tools for debugging both SQL and HTML/JavaScript, so it’s important to take each IDE’s debugging features into account, and determine which of these your PHP application will need–before you actually need them.