Add events on Consumer and RpcServer

[thomasvargiu]

In order to use any class and to maintain a clean code, will be useful to have a CallbackInterface to be implemented in any class.

It's better to implement events. The idea is to implement events on Consumer and RpcServer and use classes that implements ListenerAggregateInterface to handle events.

[thomasvargiu]

The configuration can be like this:

<?php

return [
    'humus_amqp_module' => [
        'consumers' => [
            'my-consumer' => [
                'queues' => array(
                    'my-queue',
                ),
                'auto_setup_fabric' => true,
                'listeners' => [
                    'Application\\My\\Listener'
                ],
            ],
        ],
    ]
];

An example of a listener can be:

<?php

namespace MyModule\Listener;

use Zend\EventManager\EventInterface;
use Zend\EventManager\EventManagerInterface;
use Zend\EventManager\ListenerAggregateInterface;
use Zend\EventManager\ListenerAggregateTrait;

class ConsumerListener implements ListenerAggregateInterface
{
    use ListenerAggregateTrait;

    /**
     * @param EventManagerInterface $events
     * @return void
     */
    public function attach(EventManagerInterface $events)
    {
        $this->listeners[] = $events->attach('delivery', [$this, 'onDelivery']);
        $this->listeners[] = $events->attach('flush', [$this, 'onFlush']);
        $this->listeners[] = $events->attach('error', [$this, 'onError']);
    }

    /**
     * @param EventInterface $e
     */
    public function onDelivery(EventInterface $e)
    {
        // my code here
    }

    /**
     * @param EventInterface $e
     */
    public function onFlush(EventInterface $e)
    {
        // my code here
    }

    /**
     * @param EventInterface $e
     */
    public function onError(EventInterface $e)
    {
        // my code here
    }
}

Advantages:

• No logger dependency on Consumer, an apposite listener can be attached if logging is required
• Flexible: can be attached many listeners, to handle anything