Was sind Laravel-Middlewares?

<?php
namespace App\Http\Middleware;
use Illuminate\Auth\Middleware\Authenticate as Middleware;
class Authenticate extends Middleware
{
    /**
     * Get the path the user should be redirected to when they are not authenticated.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return string
     */
    protected function redirectTo($request)
    {
        if (! $request->expectsJson()) {
            return route(&#39;login&#39;);
        }
    }
}

<?php
namespace App\Http\Middleware;
use Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode as Middleware;
class CheckForMaintenanceMode extends Middleware
{
    /**
     * The URIs that should be reachable while maintenance mode is enabled.
     *
     * @var array
     */
    protected $except = [
        //
    ];
}

<?php
namespace App\Http\Middleware;
use Illuminate\Cookie\Middleware\EncryptCookies as Middleware;
class EncryptCookies extends Middleware
{
    /**
     * The names of the cookies that should not be encrypted.
     *
     * @var array
     */
    protected $except = [
        //
    ];
}

<?php
namespace App\Http\Middleware;
use Closure;
use Illuminate\Support\Facades\Auth;
class RedirectIfAuthenticated
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @param  string|null  $guard
     * @return mixed
     */
    public function handle($request, Closure $next, $guard = null)
    {
        if (Auth::guard($guard)->check()) {
            return redirect(&#39;/home&#39;);
        }
        return $next($request);
    }
}

<?php
namespace App\Http\Middleware;
use Illuminate\Foundation\Http\Middleware\TrimStrings as Middleware;
class TrimStrings extends Middleware
{
    /**
     * The names of the attributes that should not be trimmed.
     *
     * @var array
     */
    protected $except = [
        &#39;password&#39;,
        &#39;password_confirmation&#39;,
    ];
}

<?php
namespace App\Http\Middleware;
use Illuminate\Http\Request;
use Fideloper\Proxy\TrustProxies as Middleware;
class TrustProxies extends Middleware
{
    /**
     * The trusted proxies for this application.
     *
     * @var array|string
     */
    protected $proxies;
    /**
     * The headers that should be used to detect proxies.
     *
     * @var int
     */
    protected $headers = Request::HEADER_X_FORWARDED_ALL;
}

<?php
namespace App\Http\Middleware;
use Illuminate\Foundation\Http\Middleware\VerifyCsrfToken as Middleware;
class VerifyCsrfToken extends Middleware
{
    /**
     * Indicates whether the XSRF-TOKEN cookie should be set on the response.
     *
     * @var bool
     */
    protected $addHttpCookie = true;
    /**
     * The URIs that should be excluded from CSRF verification.
     *
     * @var array
     */
    protected $except = [
        //
    ];
}