Laravel Middleware

Hey Guys….

Today we going to be talking about another important component of Laravel:

Middleware

Middleware is another essential component of Laravel and provide a convenient mechanism for filtering HTTP requests entering your application. For example, let us assume a situation where this middleware of Laravel checks for an authenticated user of your project. In this case 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.

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

Middleware can be defined as a middle-man or interface acting in coordination between a request and a response. As mentioned in the above test scenario, if the user is not authenticated, then your project may redirect that user from login.php to index.php page.

 

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
{
    /**
     * Handle an incoming request.
     *
     * @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”), 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.

Before & After Middleware

Whether a middleware runs before or after a request depends on the middleware itself. For example, the following middleware would perform some task before the request is handled by the application:

However, this middleware would perform its task after the request is handled by the application:

Registering Middleware

Global Middleware

If you want a middleware to run during every HTTP request to your application, list the middleware class in the $middleware property of your app/Http/Kernel.php class.

Assigning Middleware To Routes

If you would like to assign middleware to specific routes, you should first assign the middleware a key in your app/Http/Kernel.php file. By default, the $routeMiddleware property of this class contains entries for the middleware included with Laravel. To add your own, append it to this list and assign it a key of your choosing:

Once the middleware has been defined in the HTTP kernel, you may use the middleware method to assign middleware to a route:

When assigning middleware, you may also pass the fully qualified class name:

Middleware Parameters

Middleware can also receive additional parameters. For example, if your application needs to verify that the authenticated user has a given “role” before performing a given action, you could create a CheckRole middleware that receives a role name as an additional argument.

 

Additional middleware parameters will be passed to the middleware after the $next argument:

Middleware parameters may be specified when defining the route by separating the middleware name and parameters with a :. Multiple parameters should be delimited by commas:

That’s it for this weeks blog about Laravel.

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