AbstractPlugin.php

<?php

namespace Proxy\Plugin;

use Proxy\Event\ProxyEvent;

abstract class AbstractPlugin
{
    const EVENT_LISTENERS = [
        'request.before_send' => 'onBeforeRequest',
        'request.sent' => 'onHeadersReceived',
        'curl.callback.write' => 'onCurlWrite',
        'request.complete' => 'onCompleted',
    ];
    
    // apply these methods only to those events whose request URL passes this filter
    protected $url_pattern;

    public function onBeforeRequest(ProxyEvent $event)
    {
        // fired right before a request is being sent to a proxy
    }

    public function onHeadersReceived(ProxyEvent $event)
    {
        // fired right after response headers have been fully received - last chance to modify before sending it back to the user
    }

    public function onCurlWrite(ProxyEvent $event)
    {
        // fired as the data is being written piece by piece
    }

    public function onCompleted(ProxyEvent $event)
    {
        // fired after the full response=headers+body has been read - will only be called on "non-streaming" responses
    }

    final public function subscribe($dispatcher)
    {
        foreach (self::EVENT_LISTENERS as $event_name => $listener) {
            $dispatcher->addListener($event_name, function ($event) use ($event_name) {
                $this->route($event_name, $event);
            });
        }
    }

    // dispatch based on filter
    final private function route($event_name, ProxyEvent $event)
    {
        $url = $event['request']->getUri();

        // url filter provided and current request url does not match it
        if ($this->url_pattern) {
            if (starts_with($this->url_pattern, '/') && preg_match($this->url_pattern, $url) !== 1) {
                return;
            } else if (stripos($url, $this->url_pattern) === false) {
                return;
            }
        }

        // Call the handler for this event
        [$this, self::EVENT_LISTENERS[$event_name]]($event);
    }
}