本文主要学习总结下Route,Middleware,Controller间参数传递。开发时经常碰到类似场景：有时需要在Middleware中读取Route中设置的middleware parameter和route parameter，有时也需要在Controller@Action中读取Middleware中设置的参数。

先假设路由是：

Route::group(['prefix' => 'route', 'namespace' => 'RouteParameter'], function () {    // route/user/{user}/role/{role}, route parameter是{user}, {role}    Route::group(['middleware' => 'route.parameter'], function () {        Route::resource('user.role', 'RouteParameterToMiddlewareController');    });    // route/advisor, middleware parameter是 'advisor', 'show', 'comment'    Route::group(['middleware' => 'middleware.parameter:advisor,show,comment'], function () {        Route::resource('advisor', 'MiddlewareParameterToMiddlewareController');    });        // /route/controller, middleware parameter是 'client'    Route::group(['middleware' => 'middleware.controller:client'], function () {        Route::resource('controller', 'MiddlewareToController');    });});

路由对应的控制器是：

namespace App\Http\Controllers\RouteParameter;use Illuminate\Http\Request;use App\Http\Controllers\Controller;class RouteParameterToMiddlewareController extends Controller{    public function show($user, $role)    {            }}namespace App\Http\Controllers\RouteParameter;use Illuminate\Http\Request;use App\Http\Controllers\Controller;class MiddlewareParameterToMiddlewareController extends Controller{    public function index()    {        return 'All';    }}

并且在Kernel.php中注册中间件：

$routeMiddlewares = []    ...        'route.parameter'       => \App\Http\Middleware\RouteParameter::class,    'middleware.parameter'  => \App\Http\Middleware\MiddlewareParameter::class,    'middleware.controller' => \App\Http\Middleware\ControllerParameter::class,;

Passing Route Parameters to Middleware

在中间件route.parameter中读取路由参数有三种方式：$request->route($parameter_name);$request->route()->parameter($parameter_name);$request->route()->parameters()，代码如下：

    route('user');        $user = $request->route()->parameter('user'); // {user}        $role = $request->route()->parameter('role'); // {role}        dd($user, $role);        $parameters = $request->route()->parameters(); // ['user' => {user}, 'role' => {role}]        dd($parameters['user'], $parameters['role']);        return $next($request);    }}

Passing Middleware Parameters to Middleware

在中间件middleware.parameter中读取中间件参数只需要在handle()中映射上对应的参数变量就行，就和在Controller@Action中获取路由参数一样：

namespace App\Http\Middleware;use Auth;use Closure;use Illuminate\Http\Response;class MiddlewareParameter{    /**     * Handle an incoming request.     *     * @param  \Illuminate\Http\Request $request     * @param  \Closure                 $next     * @param                           $role     * @param                           $action     * @param                           $data     *     * @return mixed     */    public function handle($request, Closure $next, $role, $action, $data)    {        dd($role, $action, $data); // 'advisor', 'show', 'comment'        if (Auth::check() && (Auth::user()->type === $role)) {            return $next($request);        }        return abort(Response::HTTP_UNAUTHORIZED, 'You must log in to access the resource.', [            'Set-Cookie' => 'Laravel=0; path=/; Expires=Thu, 01-Jan-1970 00:00:00 GMT; Secure',        ]);    }}

Passing Parameters in Middleware to Controller

有时需要在中间中把参数传递到控制器中，则可以通过Request对象作为传输管道，代码如：

namespace App\Http\Middleware;use Closure;class ControllerParameter{    /**     * Handle an incoming request.     *     * @param  \Illuminate\Http\Request  $request     * @param  \Closure  $next     * @return mixed     */    public function handle($request, Closure $next, $role)    {        $request->attributes->add(compact('role')); // 'client'        return $next($request);    }}

控制器中使用Request对象获取$role参数：

namespace App\Http\Controllers\RouteParameter;use Illuminate\Http\Request;use App\Http\Controllers\Controller;class MiddlewareToController extends Controller{    public function index(Request $request)    {        dd($request->get('role'));    }}

总结：Route,Middleware,Controller之间传递参数这个知识点会经常在设计代码时用到，还有从Route中传递参数到Controller中，这个就更是经常要用到的，也简单。总结下这几个知识点，便于查阅。

招聘