laravel_middeware.php

<?php
// create middleware with below command :
// php artisan make:middleware My_middelware_name
// then define this in Kernel.php

// we have 2 types middelware : 1-before  2-after

// example for 'before middleware':
public function handle($request, Closure $next)
    {
        if($request->has('name')){
            return $next($request);
        }
        
        return abort(404);
    }


// example for 'after middleware' :
public function handle($request, Closure $next)
    {

        /** @var Response $result */
        $result = $next($request);
        $result->header('myName', '123');

        return $result;
    }


// define middleware for a controller
public function __construct()
    {
        $this->middleware('guest');
    }



// define middleware for one or multi function in controller
public function __construct()
    {
        $this->middleware('guest')->only(['method1', 'method2']);
    }



// define multi middleware together :
// in Kernel.php
protected $middlewareGroups = [
        'custom.middle' => [
                \App\Http\Middleware\EncryptCookies::class,
                \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,   
         ]
]
// now just use this :
Route::get('/user', 'UserController')->middleware('custon.middle');    



// pass parameters to middleware 
Route::get('/', 'HomeController', [
        'middleware' => 'allow:12', // pass 'allow' param with default value 12 
]);

public function handle($request, Closure $next, $value)
    {
        if($request->has('name') && $request->allow == $value){
            return $next($request);
        }

        return abort(404);
    }