The Debug Component
The Debug Component¶
The Debug component provides tools to ease debugging PHP code.
New in version 2.3: The Debug component was introduced in Symfony 2.3. Previously, the classes were located in the HttpKernel component.
Installation¶
You can install the component in many different ways:
- Install it via Composer (
symfony/debugon Packagist); - Use the official Git repository (https://github.com/symfony/debug).
Then, require the vendor/autoload.php file to enable the autoloading mechanism
provided by Composer. Otherwise, your application won't be able to find the classes
of this Symfony component.
Usage¶
The Debug component provides several tools to help you debug PHP code. Enabling them all is as easy as it can get:
use Symfony\Component\Debug\Debug;
Debug::enable();
The enable() method registers an
error handler and an exception handler. If the ClassLoader component is available, a special class loader
is also registered.
Read the following sections for more information about the different available tools.
Caution
You should never enable the debug tools in a production environment as they might disclose sensitive information to the user.
Enabling the Error Handler¶
The ErrorHandler class catches PHP errors
and converts them to exceptions (of class ErrorException or
FatalErrorException for PHP
fatal errors):
use Symfony\Component\Debug\ErrorHandler;
ErrorHandler::register();
Enabling the Exception Handler¶
The ExceptionHandler class catches
uncaught PHP exceptions and converts them to a nice PHP response. It is useful
in debug mode to replace the default PHP/XDebug output with something prettier
and more useful:
use Symfony\Component\Debug\ExceptionHandler;
ExceptionHandler::register();
Note
If the HttpFoundation component is available, the handler uses a Symfony Response object; if not, it falls back to a regular PHP response.
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.