Debugging¶

Xdebug¶

First of all: best practice to debug PHP code is using an IDE (like PhpStorm or Visual Studio Code) with Xdebug. Advantages are:

• You can investigate the values of variables and class properties when setting a breakpoint.
• You can move forward line by line and see how the variables and properties change.
• You can also step into calling methods and functions.
• You see the calling code as a stack trace.

DebugUtility::debug()¶

The TYPO3 Core provides a simple debug() (defined in EXT:core/Classes/Core/GlobalDebugFunctions.php). It wraps around \TYPO3\CMS\Core\Utility\DebugUtility::debug() and will output debug information only if it matches a set of IP addresses (defined in $GLOBALS['TYPO3_CONF_VARS']['SYS']['devIPmask']).

For example, the following code:

use TYPO3\CMS\Core\Utility\DebugUtility;

class ModuleController extends ActionController implements LoggerAwareInterface
{
    protected function debugCookies() {
        DebugUtility::debug($_COOKIE, 'cookie');
    }
}

will produce such an output:

In general, look at class \TYPO3\CMS\Core\Utility\DebugUtility for useful debugging tools.