Slim application middleware must subclass \Slim\Middleware and implement a public call() method. The call()
method does not accept arguments. Middleware may implement its own constructor, properties, and methods. I encourage
you to look at Slim’s built-in middleware for working examples (e.g. Slim/Middleware/ContentTypes.php or
Slim/Middleware/SessionCookie.php).
This example is the simplest implementation of Slim application middleware. It extends \Slim\Middleware,
implements a public call() method, and calls the next inner middleware.
<?php
class MyMiddleware extends \Slim\Middleware
{
public function call()
{
$this->next->call();
}
}