Laravel - Middleware

Laravel - Middleware 

Define Middleware

Middleware acts as a middle man between request and response. It is a type of filtering mechanism. For example, Laravel includes a middleware that verifies whether user of the application is authenticated or not. If the user is authenticated, he will be redirected to the home page otherwise, he will be redirected to the login page.

Middleware can be created by executing the following command −

php artisan make:middleware

Replace the with the name of your middleware. The middleware that you create can be seen at app/Http/Middleware directory.

Let us now create AgeMiddleware. To create that, we need to execute the following command −

C:\xampp\htdocs\laraveldev>php artisan make:middleware AgeMiddleware

After successful execution of the command, you will receive the following output −
Middleware created succesfully.

AgeMiddlware will be created at app/Http/Middleware. The newly created file will have the following code already created for you.

<?php
namespace App\Http\Middleware;
use Closure;

class AgeMiddleware {
   public function handle($request, Closure $next) {
      return $next($request);
   }
}

Register Middleware
We need to register each and every middleware before using it. There are two types of Middleware in Laravel.

Global Middleware
Route Middleware
The Global Middleware will run on every HTTP request of the application, whereas the Route Middleware will be assigned to a specific route. The middleware can be registered at app/Http/Kernel.php. This file contains two properties $middleware and $routeMiddleware. $middleware property is used to register Global Middleware and $routeMiddleware property is used to register route specific middleware.

To register the global middleware, list the class at the end of $middleware property.

protected $middleware = [
   \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class,
   \App\Http\Middleware\EncryptCookies::class,
   \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
   \Illuminate\Session\Middleware\StartSession::class,
   \Illuminate\View\Middleware\ShareErrorsFromSession::class,
   \App\Http\Middleware\VerifyCsrfToken::class,
];

To register the route specific middleware, add the key and value to $routeMiddleware property.

protected $routeMiddleware = [
   'auth' => \App\Http\Middleware\Authenticate::class,
   'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
   'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
];

The following is the code for app/Http/Kernel.php

<?php
namespace App\Http;
use Illuminate\Foundation\Http\Kernel as HttpKernel;

class Kernel extends HttpKernel {
   protected $middleware = [
      \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class,
      \App\Http\Middleware\EncryptCookies::class,
      \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
      \Illuminate\Session\Middleware\StartSession::class,
      \Illuminate\View\Middleware\ShareErrorsFromSession::class,
      \App\Http\Middleware\VerifyCsrfToken::class,
   ];
  
   protected $routeMiddleware = [
      'auth' => \App\Http\Middleware\Authenticate::class,
      'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
      'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
      'Age' => \App\Http\Middlware\AgeMiddleware::class,
   ];
}

Middleware Parameters
We can also pass parameters with the Middleware. For example, if your application has different roles like user, admin, super admin etc. and you want to authenticate the action based on role, this can be achieved by passing parameters with middleware. The middleware that we create contains the following function and we can pass our custom argument after the $next argument.

Create RoleMiddleware by executing the following command −

C:\xampp\htdocs\laraveldev>php artisan make:middleware RoleMiddleware 
After successful execution, you will receive the following output
Middleware created succesfully.

Add the following code in the handle method of the newly created RoleMiddlewareat app/Http/Middleware/RoleMiddleware.php.

<?php
namespace App\Http\Middleware;
use Closure;

class RoleMiddleware {
   public function handle($request, Closure $next, $role) {
      echo "Role: ".$role;
      return $next($request);
   }
}

Register the RoleMiddleware in app\Http\Kernel.php file.

protected $routeMiddleware = [
        'auth' => \App\Http\Middleware\Authenticate::class,
        'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
        'can' => \Illuminate\Foundation\Http\Middleware\Authorize::class,
        'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
        'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class,
        'Role' => \App\Http\Middleware\RoleMiddleware::class, //add RoleMiddleware 
    ];

Execute the following command to create TestController −

C:\xampp\htdocs\laraveldev>php artisan make:controller TestController 
After successful execution, you will receive the following output −
Controller created successfully

Copy the following code to app/Http/TestController.php file.

<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use App\Http\Requests;
use App\Http\Controllers\Controller;

class TestController extends Controller {
   public function index(){
      echo "
Test Controller.";
   }
}

Add the following line of code in app/Http/routes.php file.

Route::get('role',[
   'middleware' => 'Role:editor',
   'uses' => 'TestController@index',
]);

Visit the following URL to test the Middleware with parameters http://localhost:8000/role