php-debugbar/docs/server_handlers.md

Server handlers

Some widgets one the client side debugbar need to execute commands on the server side. The DebugBar provides the infrastructure to do so but you will need to create an endpoint to receive commands.

The front controller

Commands are handled using a DebugBar\ServerHandler\FrontController instance. You can instanciate one using DebugBar\DebugBar::createServerHandlerFrontController().

$fc = $debugbar->createServerHandlerFrontController();
$fc->handle();

Calling handle() will use data from the $_REQUEST array and echo the output. The function also supports input from other source if you provide an array as first argument. It can also return the data instead of echoing (use false as second argument) and not send the content-type header (use false as third argument).

Once you have setup the fornt controller, tell the JavascriptRenderer its url.

$renderer->setServerHandlerUrl('server.php');

When the FrontController is instanciated, all collectors which implement DebugBar\ServerHandler\ServerHandlerInterface or DebugBar\ServerHandler\ServerHandlerFactoryInterface will be registered. You can register more server handlers using FrontController::registerHandler().

Creating server handlers

Handlers can be any class implementing the DebugBar\ServerHandler\ServerHandlerInterface. Two methods are required: getName() and getCommandNames(). The first one must return a string with this handler's name and the second ones an array of string listing allowed methods to be called.

A command is simply a method which will receive two arguments, a $request array containing the parameters and the DebugBar instance.

class MyServerHandler implements DebugBar\ServerHandler\ServerHandlerInterface
{
    public function getName()
    {
        return 'my';
    }

    public function getCommandNames()
    {
        return array('ping');
    }

    public function ping($request, $debugbar)
    {
        return 'pong';
    }
}

When a command method is called, its return will be sent back as JSON to the client.

Open handler

The open handler allows you to re-open previously executed requests saved using the storage mechanism.

The OpenHandler is automatically registered when a FrontController is instanciated and a storage is defined on the debugbar.

This adds a button in the top right corner of the debug bar which allows you to browse and open previous sets of collected data.