How to debug PHP scripts?

 

Debugging

When a computer program does not work properly, we are raising the issue of bugs. A bug can be described as an error in the code that causes it to produce an incorrect result or to behave unexpectedly.

In this tutorial, we will learn how to debug PHP scripts using Xdebug and NetBeans IDE. A debugger is a tool that provides a programmer with important information about the inner state of the program during its execution.

Debugging with print

Here are the basic steps to debug your PHP script with print:

• Check the document type declaration.

• Make sure that PHP tags are properly open and closed.

• Use echo or print statements to display important information (such as form data) in order to verify that the right information is being received by scripts.

• If you have a bug involving arrays, use var_dump or var_export instead of print_r.

Debugging by using var_dump() function

var_dump() function is used to display structured information (type and value) about one or more variables. It returns NULL if nothing is passed in as an argument. The dumped information includes its type and value, e.g., string(5) 'Hello' or boolean TRUE.

In PHP 7, the var_dump() function will return the same output as dump_function(). Both functions will have new improvements that include improved HTML formatting and a better color highlighting of type and value. To use var_dump(), simply pass in a variable name or expression to be evaluated:

// Outputs: boolean Trueecho "Printing a simple boolean...";var_dump($someBoolean);echo "";

// Outputs: array (size=4) 'first' => int 1 'second' => int 2 'third' => int 3 'fourth' => int 4echo "Printing an array...";var_dump($someArray);The syntax of the var_dump() function looks like this: var_dump([$value1 [, $value2 ...]])

Debugging with a debugger (php.ini set-up)

You can use a debugger to set breakpoints and step through your code. For example, the following snippet shows how you can use PhpStorm’s Xdebug configuration for the IDE:

The second line tells PHP to call the xdebug_break() function when it encounters this statement in the script being executed. This is where execution will stop when it reaches this point, and you can then inspect variable values, stack values, and more from within your IDE.

Using the Xdebug PHP extension for debugging

If you want to debug your PHP scripts, Xdebug is a popular solution. You can use it step through your code as well as profile your code and generate nice graphs that help you see where optimizations are needed.

Xdebug is available for most operating systems and the installation process is relatively simple in most cases. Some operating systems even have packages ready for installation with just a single click and others provide an easy-to-use installer. If you don't want to install anything on your system but still would like to use Xdebug, there are also precompiled Windows binaries available which will install into your existing PHP installation (by using PECL).

PHP offers a variety of methods for debugging your script which is powerful tools for testing and maintaining your programs and content.

Debugging is the process of finding and fixing errors in your code. The PHP debugger can be an essential tool in this process if you know how to use it properly. Luckily, there are a few tricks that can make debugging your programs and content much easier.

The first thing to note is that debugging is one of the most important skills for a programmer to have because it can be used in many situations. For example, you may want to debug a script before using it on your website or program. Or maybe you’re working on projects with other programmers and need to check their work for bugs as well! Whatever the case may be, knowing how debug effectively will save time and effort when trying to find problems later down the road - which means less frustration at having spent hours searching through pages of text looking for that elusive typo…