如何在Slim v3中访问中间件类中的$ container？

Question

I've been reading that in Slim v2, $app was bound to the middleware class. I'm finding this not to be the case in v3? Below is my middleware class, but I'm just getting undefined:

<?php
namespace CrSrc\Middleware;

class Auth
{
    /**
     * Example middleware invokable class
     *
     * @param  \Psr\Http\Message\ServerRequestInterface $request  PSR7 request
     * @param  \Psr\Http\Message\ResponseInterface      $response PSR7 response
     * @param  callable                                 $next     Next middleware
     *
     * @return \Psr\Http\Message\ResponseInterface
     */
    public function __invoke($request, $response, $next)
    {
        // before

var_dump($this->getContainer()); // method undefined
var_dump($this->auth); exit; // method undefined
        if (! $this->get('auth')->isAuthenticated()) {
            // Not authenticated and must be authenticated to access this resource
            return $response->withStatus(401);
        }

        // pass onto the next callable
        $response = $next($request, $response);

        // after


        return $response;
    }
}

What's the correct way to access the DI container within middleware? I'm guessing there ought to be a way?

Answer 1

A bit late to the party but might help others... You have to inject your container when instantiating the middleware

$container = $app->getContainer();
$app->add(new Auth($container));

And your middleware needs a constructor

<?php
namespace CrSrc\Middleware;

class Auth
{

    private $container;

    public function __construct($container) {
        $this->container = $container
    }

    /**
     * Example middleware invokable class
     *
     * @param  \Psr\Http\Message\ServerRequestInterface $request  PSR7 request
     * @param  \Psr\Http\Message\ResponseInterface      $response PSR7 response
     * @param  callable                                 $next     Next middleware
     *
     * @return \Psr\Http\Message\ResponseInterface
     */
    public function __invoke($request, $response, $next)
    {
        // $this->container has the DI

    }
}

LE: Expanding a bit the initial answer, the container gets injected in the constructor if you supply the middleware as a class string

$app->add('Auth');

or

$app->add('Auth:similarToInvokeMethod')

Answer 2

As far as I understand the code, Slim (v3) works the following way:

• if you pass a closure as middleware, then it calls bindTo with container as param.

• if you pass a class/string that resolves to a class, then Slim creates the instance and passes the container as param to the constructor

   <?php $app->add(Auth); 

• otherwise (eg if you add a middleware instance created earlier) then it looks like you have to take care of passing all necessary references.