Laravel document sorting 8. Middleware

Preface ：Laravel Document sorting , Only for record , Nothing else .

1、 What is Middleware ？
See the word and know the meaning , In the middle , A component used to handle a business .http middleware , It provides a convenient mechanism to filter the data entering the application http request , Only after being filtered by middleware , The program will continue to run .

2、 Common middleware functions
Auth middleware , Verify the identity of the user
Cors middleware , Responsible for responding to all departing programs , Add appropriate headers
Log Middleware , Responsible for recording all incoming requests to the application .

3、laravel Where is the middleware of the framework ？
App/Http/Middleware

4、 How to create a middleware ？
php artisan make:middleware OldMiddleware

Ps： It can be created manually , It can also be done through artisan Command to generate .
This command will be in app/Http/Middleware Set a name in the directory as OldMiddleware Class

5、OldMiddleware Middleware instance
<?php

namespace App\Http\Middleware;

use Closure;

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

        return $next($request);
    }

}
Age Less than 200, The middleware will return http Request relocation to client , otherwise , Progress incoming applications .

6、 If you wish http request , Through your middleware , What to do with it ？
Add middleware to app/Http/kernel.php Of documents $middleware Properties of the .

7、 If you want to specify middleware for a route separately , How to deal with it ？
a、 stay app/Http/Kernel.php Of documents $routeMiddleware Add a set of customized key values of the middleware to the attribute , as follows ：
// stay App\Http\Kernel Within class ...

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

b、 In routing file , Use the added middleware key name for routing , that will do .
middleware , Once in a kernel The document specifies , In the routing options , Use middleware Key value assignment ：
Route::get('admin/profile', ['middleware' => 'auth', function () {
    //
}]);

c、 You can also use multiple middleware for a route , as follows ：
Route::get('/', ['middleware' => ['first', 'second'], function () {
    //
}]);

d、 except c This method , You can also chain call middleware Method
Route::get('/', function () {
    //
}])->middleware(['first', 'second']);

8、 Middleware parameters
Before running an operation , To verify whether the current user has this 【 role 】, You can create a role middleware , Receive role name , As an additional parameter ：
<?php

namespace App\Http\Middleware;

use Closure;

class RoleMiddleware
{
    /**
     * Run request filtering
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @param  string  $role
     * @return mixed
     */
    public function handle($request, Closure $next, $role)
    {
        if (! $request->user()->hasRole($role)) {
            // If the user has no specific 「 role 」 Words
        }

        return $next($request);
    }

}
In routing , Colons can be used ： To interval the middleware name and assignment parameters , Multiple parameters can be separated by commas
Route::put('post/{id}', ['middleware' => 'role:editor', function ($id) {
    //
}]);

9、Terminable middleware
This middleware , It's to satisfy http After the request is sent to the browser , To deal with session Storage operation .
<?php

namespace Illuminate\Session\Middleware;

use Closure;

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

    public function terminate($request, $response)
    {
        // preservation session data ...
    }
}

Once the middleware is defined , You need to add it to kernel In the global middleware list of the file .

When you call terminate() When the method is used ,laravel A new middleware instance will be parsed from the server container .

If you wish handle() terminate() Methods are invoked using consistent middleware , that , You need to use containers singleton Method register middleware .