What is Laravel 8 middleware ?

Aman Jain,

Laravel middleware is a mechanism to filter the http request and response. As the name implies that middleware so it’s middle between the request and response.

we can change or validate request and response using the Laravel middleware. There is so many use cases of middleware like authentication, validating token, change request paras, validating a request, validating csrf etc.

Creating a middleware

Creating a middleware is easy using make:middleware artisan command or we can create manually

Artisan command for make middleware

php artisan make:middleware middleware_name

Now, let’s create a middleware for our application

php artisan make:middleware CheckBlacklist

Above command will create a middleware CheckBlacklist in folder \app\http\Middleware

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;

class CheckBlacklist
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle(Request $request, Closure $next)
    {
        if (auth()->user()->is_blacklisted == 1) {
            return response()->json('Your account is blacklisted by admin');
        }
        return $next($request);
    }
}

Here, we checked user is blacklisted by admin or not, if user is blacklisted then return the response with message.

Registering middleware

We have created middleware but not registered yet, so to register our new middleware with our Laravel application we need to register it in app/http/kernel.php 

Registering middleware globally

To register the middleware globally we need to assign it to $routeMiddleware property of app/Http/Kernel.php


use Illuminate\Foundation\Http\Kernel as HttpKernel;


class Kernel extends HttpKernel
{
    ....


    /**
     * The application's route middleware.
     *
     * These middleware may be assigned to groups or used individually.
     *
     * @var array
     */
    protected $middleware = [
        ....
        'checkBlacklist' => \App\Http\Middleware\CheckBlacklist::class,
    ];
}

Middleware to specific routes

We can also assign routes to specific routes using $routeMiddleware property of app/Http/Kernel.php


use Illuminate\Foundation\Http\Kernel as HttpKernel;


class Kernel extends HttpKernel
{
    ....


    /**
     * The application's route middleware.
     *
     * These middleware may be assigned to groups or used individually.
     *
     * @var array
     */
    protected $routeMiddleware = [
        ....
        'checkBlacklist' => \App\Http\Middleware\CheckBlacklist::class,
    ];
}

Attaching Middleware to route


Route::get('/create-post',[PostController::class, 'create'])->middleware(CheckBlacklist::class);

Multiple middleware to route


Route::get('/create-post',[PostController::class, 'create'])
->middleware([CheckBlacklist::class,SecoundMiddleware::class]);

Middleware to group of routes

Route::group(['middleware' =>CheckBlacklist::class ], function () {
    //
});

Parametrized Middleware

In some cases we need to pass the pass the param to middleware to check some specific conditions like user role for page. We just need to add a extra param to handle function.

Take a quick example, here $role is param

public function handle($request, Closure $next, $role)
{
    if (! $request->user()->hasRole($role)) {
        // Redirect...
    }

    return $next($request);
}

Ataching to the paramo to route

Route::post('edit-post/{id}', ['middleware' => 'role:editor', function ($id) {
    //
}]);
beenhere

Also Read :

Create custom middleware in Laravel 8

Php Laravel

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