Laravel5.1注册中间件的三种场景

在Laravel中注册中间件主要有三种场景，一种给控制器中的方法进行注册，一种是给整个控制器进行注册，最后一种是给全局注册中间件。

• 1、在控制器中的方法中注册中间件
  这种需求是最为常见，这个例子是给IndexController中的index方法添加中间件。

Route::get('/', ['middleware'=>['App\Http\Middleware\EmailMiddleware'],'uses'=>'IndexController@index']);

• 2、在整个控制器中注册中间件
  这种需求有的时候也会出现，如果给整个控制器中注册中间件，那么这个控制器中的所有方法都注册了该中间件。跟我一起来找到答案！

控制器基类（Controller.php）

首先来看一下控制器基类，可以看到Controller类继承了BaseController类，而BaseController的路径是Illuminate\Routing\Controller，然后我们来看看Laravel的源码。

<?php
namespace App\Http\Controllers;
use Illuminate\Foundation\Bus\DispatchesJobs;
use Illuminate\Routing\Controller as BaseController;
use Illuminate\Foundation\Validation\ValidatesRequests;
use Illuminate\Foundation\Auth\Access\AuthorizesRequests;
abstract class Controller extends BaseController
{
    use AuthorizesRequests, DispatchesJobs, ValidatesRequests;
}

BaseController类

从源码中我们可以看到有一个属性为middleware，这个middleware属性就是我们要找的，所以只要在需要注册的控制器下使用这个属性即可完成注册。

protected $middleware = [];

<?php
namespace Illuminate\Routing;
use BadMethodCallException;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
abstract class Controller
{
    /**
     * The middleware registered on the controller.
     *
     * @var array
     */
    protected $middleware = [];
    /**
     * Register middleware on the controller.
     *
     * @param  array|string|\Closure  $middleware
     * @param  array   $options
     * @return \Illuminate\Routing\ControllerMiddlewareOptions
     */
    public function middleware($middleware, array $options = [])
    {
        foreach ((array) $middleware as $m) {
            $this->middleware[] = [
                'middleware' => $m,
                'options' => &$options,
            ];
        }
        return new ControllerMiddlewareOptions($options);
    }
    /**
     * Get the middleware assigned to the controller.
     *
     * @return array
     */
    public function getMiddleware()
    {
        return $this->middleware;
    }
    /**
     * Execute an action on the controller.
     *
     * @param  string  $method
     * @param  array   $parameters
     * @return \Symfony\Component\HttpFoundation\Response
     */
    public function callAction($method, $parameters)
    {
        return call_user_func_array([$this, $method], $parameters);
    }
    /**
     * Handle calls to missing methods on the controller.
     *
     * @param  array   $parameters
     * @return mixed
     *
     * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
     */
    public function missingMethod($parameters = [])
    {
        throw new NotFoundHttpException('Controller method not found.');
    }
    /**
     * Handle calls to missing methods on the controller.
     *
     * @param  string  $method
     * @param  array   $parameters
     * @return mixed
     *
     * @throws \BadMethodCallException
     */
    public function __call($method, $parameters)
    {
        throw new BadMethodCallException("Method [{$method}] does not exist.");
    }

给整个控制器注册中间件

我们选用系统的Authenticate中间件来举例，这个中间件是用于检测用户是否登录。

注意：中间件的名称为键，值可以是一个空数组

 protected $middleware = ['\App\Http\Middleware\Authenticate'=>[]];

• 3、全局注册中间件

打开app/Http/Kernel.php，这是一个内核文件，可以看到一个属性$middleware，我们只需要将我们自定义的中间件的路径添加到这个$middleware 这个属性中即可。

此外还有一个$routeMiddleware属性，使用这个属性可以根据路由来注册中间件。
我们的路由有：goods/info，goods/detail两个路由器
我们可以将$routeMiddleware属性添加一行

'goods.*' => \App\Http\Middleware\GoodsMiddleware::class,

<?php

namespace App\Http;

use Illuminate\Foundation\Http\Kernel as HttpKernel;

class Kernel extends HttpKernel
{
    /**
     * The application's global HTTP middleware stack.
     *
     * @var array
     */
    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,
    ];

    /**
     * The application's route middleware.
     *
     * @var array
     */
    protected $routeMiddleware = [
        'auth' => \App\Http\Middleware\Authenticate::class,
        'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
        'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
    ];
}