Middleware

Middleware

• Introduction
• Defining Middleware
• Registering Middleware
  • Global Middleware
  • Assigning Middleware To Routes
  • Middleware Groups
• Middleware Parameters
• Terminable Middleware

Introduction

Middleware provide a convenient mechanism for filtering HTTP requests entering your application. For example, Laravel includes a middleware that verifies the user of your application is authenticated. If the user is not authenticated, the middleware will redirect the user to the login screen. However, if the user is authenticated, the middleware will allow the request to proceed further into the application.

Of course, additional middleware can be written to perform a variety of tasks besides authentication. A CORS middleware might be responsible for adding the proper headers to all responses leaving your application. A logging middleware might log all incoming requests to your application.

There are several middleware included in the Laravel framework, including middleware for authentication and CSRF protection. All of these middleware are located in the app/Http/Middleware directory.

Defining Middleware

To create a new middleware, use the make:middleware Artisan command:

php artisan make:middleware CheckAge

This command will place a new CheckAge class within your app/Http/Middleware directory. In this middleware, we will only allow access to the route if the supplied age is greater than 200. Otherwise, we will redirect the users back to the home URI.

<?php

namespace App\Http\Middleware;

use Closure;

class CheckAge
{
    /**
     * Run the request filter.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle($request, Closure $next)
    {
        if ($request->age <= 200) {
            return redirect('home');
        }

        return $next($request);
    }

}

As you can see, if the given age is less than or equal to 200, the middleware will return an HTTP redirect to the client; otherwise, the request will be passed further into the application. To pass the request deeper into the application (allowing the middleware to "pass"), simply call the $next callback with the $request.

It's best to envision middleware as a series of "layers" HTTP requests must pass through before they hit your application. Each layer can examine the request and even reject it entirely.