Laravel中间件

本文概述

• 创建一个中间件
• 应用中间件
• 检查中间件的条件

中间件充当用户和请求之间的层。这意味着, 当用户请求服务器时, 请求将通过中间件, 然后中间件将验证请求是否已通过身份验证。如果用户的请求已通过身份验证, 则该请求将发送到后端。如果用户请求未通过身份验证, 则中间件会将用户重定向到登录屏幕。

除身份验证外, 其他中间件可用于执行各种任务。例如, CORS中间件负责将标头添加到所有响应。

Laravel框架包括一些中间件, 例如身份验证和CSRF保护, 所有这些都位于app / Http / Middleware目录中。

我们可以说中间件是一个http请求过滤器, 你可以在其中检查条件。

在中间件中, 我们将讨论以下主题：

• 制作中间件
• 应用中间件
• 检查中间件的条件
• 路由中间件

创建一个中间件

输入命令php artisan make：middleware’中间件名称’。

在上面的屏幕中, 我们键入命令“ php artisan make：middleware CheckAge”, 其中CheckAge是中间件的名称。上面的窗口显示已成功创建名称为“ CheckAge”的中间件。

要查看是否已创建CheckAge中间件, 请转到你的项目。我们的项目名称为laravelproject, 因此中间件的路径为：C：\ xampp \ htdocs \ laravelproject \ app \ Http \ Middleware。

应用中间件

中间件可以应用于所有URL或某些特定的URL。

让我们将中间件应用于所有URL。

步骤1：打开kernel.php文件。如果我们想将中间件应用于所有URL, 则在中间件数组中添加中间件的路径。

<?php
namespace App\Http;
use Illuminate\Foundation\Http\Kernel as HttpKernel;
class Kernel extends HttpKernel
{
    /**
     *  The application's global HTTP middleware stack.
     *
     * These middleware are run during every request to your  application.
     *
     * @var array
     */
 protected $middleware = [ \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class, \Illuminate\Foundation\Http \Middleware\ValidatePostSize::class, \App\Http\Middleware\TrimStrings::class, \App\Http\Middleware\CheckAge
::class, \Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull::class, ];

   /**
     * The application's route middleware groups.
     *
     * @var array
     */
    
protected $middlewareGroups = [
        'web' => [
            \App\Http\Middleware\EncryptCookies::class, \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class, \Illuminate\Session\Middleware\StartSession::class, // \Illuminate\Session\Middleware\AuthenticateSession::class, \Illuminate\View\Middleware 
\ShareErrorsFromSession::class, \App\Http\Middleware\VerifyCsrfToken::class, \Illuminate\Routing\Middleware\SubstituteBindings::class, ], 'api' => [
            'throttle:60, 1', 'bindings', ], ];

    
 /**
     * The application's route middleware.
     *
     * These middleware may be assigned to groups or used individually.
     *
     *  
@var array
     */
    protected $routeMiddleware = [
        
'auth' => \Illuminate\Auth\Middleware\Authenticate::class, 'auth.basic' => \Illuminate\Auth\Middleware 
\AuthenticateWithBasicAuth::class, 'bindings' => \Illuminate\Routing\Middleware\SubstituteBindings::class, 'can' => \Illuminate\Auth\Middleware\Authorize::class, 'guest' => \App\Http\Middleware 
\RedirectIfAuthenticated::class, 'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class, ];
}

步骤2：在Git Bash窗口中键入php artisan serve命令。

步骤3：打开你已创建为中间件的CheckAge.php文件。

<?php

namespace App\Http\Middleware;

use Closure;

class CheckAge

{
    
/**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http 
\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
  public function handle($request, Closure $next)
 {
 //return "middleware";
echo "hello world";
return $next($request);
}
}

步骤4：现在, 输入URL’http：// localhost / laravelproject / public /’。

让我们将中间件应用于某些特定的路由。

步骤1：打开kernel.php文件。如果我们要将中间件应用于某些特定的路由

<?php
namespace App\Http;
use Illuminate\Foundation\Http\Kernel as HttpKernel;
class Kernel extends HttpKernel
{
    /**
     *  The application's global HTTP middleware stack.
     *
     * These middleware are run during every request to your  application.
     *
     * @var array
     */
  protected $middleware = [
   \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class, \Illuminate\Foundation\Http\Middleware\ValidatePostSize::class, \App\Http\Middleware\TrimStrings::class, \Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull::class, ];
 /**
     * The application's route middleware groups.
     *
     * @var array
     */
 protected $middlewareGroups = [
 'web' => [
  \App\Http\Middleware\EncryptCookies::class, \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class, \Illuminate\Session\Middleware\StartSession::class, // \Illuminate\Session\Middleware\AuthenticateSession::class, \Illuminate\View\Middleware \ShareErrorsFromSession::class, \App\Http\Middleware\VerifyCsrfToken::class, \Illuminate\Routing\Middleware\SubstituteBindings::class, ], 'api' => [
            'throttle:60, 1', 'bindings', ], ];
 /**
     * The application's route middleware.
     *
     * These middleware may be assigned to groups or used individually.
     *
     *  
@var array
     */
    protected $routeMiddleware = [
        
'auth' => \Illuminate\Auth\Middleware\Authenticate::class, 'auth.basic' => \Illuminate\Auth\Middleware 
\AuthenticateWithBasicAuth::class, 'bindings' => \Illuminate\Routing\Middleware\SubstituteBindings::class, 'can' => \Illuminate\Auth\Middleware\Authorize::class, 'guest' => \App\Http\Middleware 
\RedirectIfAuthenticated::class, 'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class, 'age' =>  \App\Http\Middleware\CheckAge::class ];
       
}

在上面的代码中, 我们添加了代码, 即“age”=> \ App \ Http \ Middleware \ CheckAge :: class’, 其中age是中间件的名称。现在, 我们可以将“年龄”中间件用于某些特定的路由。

步骤2：打开你已创建为中间件的CheckAge.php文件。

步骤3：在web.php文件中添加中间件代码。

Route::Get('/', function()
{
  return view('welcome');
})-> middleware('age');
Route::Get('user/profile', function()
{
  return "user profile";
});

在上面的代码中, 我们在’/’根URL中添加了中间件, 而在’user / profile’URL中未添加中间件。

输出：

当我们访问根URL时, 输出将是：

上面的输出表明, 中间件代码在显示“ hello world”时也已被访问。

当我们访问URL（即/ user / profile）时, 输出为：

上面的输出表明尚未访问中间件代码。

在URL中传递参数时。

web.php

Route::Get('/{age}', function($age)
{
  return view('welcome');
})-> middleware('age');

CheckAge.php

<?php
namespace App\Http\Middleware;
use Closure;
class CheckAge
{
 /**
 * Handle an incoming request.
 *
     
* @param
  \Illuminate\Http\Request  $request
 * @param  \Closure  $next
 * @return mixed
 */
  public function handle($request, Closure $next)
 {
 //return "middleware";
echo "this is checkage middleware";
return $next($request);
}}

输出量

检查中间件的条件

中间件也可用于检查条件。让我们通过一个例子来理解。

Route::Get('/{age}', function($age)
{
  return view('welcome');
})-> middleware('age');

<?php
namespace App\Http\Middleware;
use Closure;
class CheckAge
{
    
/**
     * Handle an incoming request.
     *
     
* @param
  \Illuminate\Http\Request  $request
    
 * @param  \Closure  $next
     * @return mixed
     */
 
   public function handle($request, Closure $next)
    
{
  //return "middleware";
if($request->age>10)
{
echo "Age is greater than 10";
}
else
{
echo"Age is not greater than 10";
}
return $next($request);
    
}}

输出：