Паттерн позволяет обработать запросы для определенных классов не прибегая к созданию класса, который содержит список получателей.
Примеры использования: обработка сообщения, используя несколько фильтров, отправка лога в различные ресурсы: в файл, в телеграм и т.д, спам-фильтры.
<?php
namespace wheekey\src\services\log;
/**
* The classic CoR pattern declares a single role for objects that make up a
* chain, which is a Handler. In our example, let's differentiate between
* middleware and a final application's handler, which is executed when a
* request gets through all the middleware objects.
*
* The base Middleware class declares an interface for linking middleware
* objects into a chain.
*/
abstract class Middleware
{
/**
* @var Middleware
*/
private $next;
/**
* This method can be used to build a chain of middleware objects.
* @param Middleware $next
* @return Middleware
*/
public function linkWith(Middleware $next): Middleware
{
$this->next = $next;
return $next;
}
/**
* Subclasses must override this method to provide their own sends. A
* subclass can fall back to the parent implementation if it can't process a
* request.
* @param string $message
*/
public function sendMessage(string $message): void
{
$this->next->sendMessage($message);
}
}
<?php
namespace wheekey\src\services\log;
use Psr\Log\LoggerInterface;
class FileLogMiddleware extends Middleware
{
/**
* @var LoggerInterface
*/
private $logger;
/**
* FileLogMiddleware constructor.
* @param LoggerInterface $logger
*/
public function __construct(LoggerInterface $logger)
{
$this->logger = $logger;
}
public function sendMessage(string $message): void
{
$this->logger->info($message);
parent::sendMessage($message);
}
}
