HandlerInterface (Message Bus)

Raxos\Contract\MessageBus\HandlerInterface is an extension point for message bus handlers in raxos/message-bus. Each handler processes one message type dispatched through the bus or a queue.

Signature

interface HandlerInterface
{
    public function handle(MessageInterface $message, Printer $printer): void;
}

The interface is templated (@template TMessage of MessageInterface), so an implementation handles one specific message type, and handle may throw any Throwable.

Methods

handle(MessageInterface $message, Printer $printer): void

Processes the given message, optionally writing output through the terminal Printer.

Notes

• One handler is written per message type, matched through the MessageInterface the message implements.
• It is used both for messages dispatched directly and for messages processed from a queue by raxos/message-bus.
• The Printer type comes from raxos/terminal, which lets a handler that runs from the command line write progress output.

Example

<?php
declare(strict_types=1);

namespace App\MessageBus;

use Override;
use Raxos\Contract\MessageBus\{HandlerInterface, MessageInterface};
use Raxos\Terminal\Printer;

final readonly class SendWelcomeEmailHandler implements HandlerInterface
{
    #[Override]
    public function handle(MessageInterface $message, Printer $printer): void
    {
        // $message is a SendWelcomeEmail instance implementing MessageInterface.

        // ... deliver the email ...

        $printer->correct('Welcome email sent');
    }
}