Laravel API 允许跨域访问

服务器A请求服务器B的接口，那么一般会出现跨域问题。全解跨域请求处理办法


XMLHttpRequest cannot load http://api.console.vms3.com/api/user. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8080' istherefore not allowed access.


意思就是服务器响应不允许跨域访问.

那我们就需要让服务器支持跨域访问, 也就是在响应头部中添加

```'Access-Control-Allow-Origin: *'
```

第一步: 创建中间件

创建 `app/Http/Middleware/AccessControlAllowOrigin.php` middleware 把 'Access-Control-Allow-Origin: *' 写入头部.
app/Http/Middleware/AccessControlAllowOrigin.php
<?phpnamespace App\Http\Middleware;use Closure;
use Illuminate\Support\Facades\Auth;class AccessControlAllowOrigin
{
/**
*
* Handle an incoming request.
*
* @param \Illuminate\Http\Request $request
* @param \Closure $next
* @return mixed
*/
public function handle($request, Closure $next)
{
header('Access-Control-Allow-Origin: *');
header("Access-Control-Allow-Credentials: true");
header("Access-Control-Allow-Methods: *");
header("Access-Control-Allow-Headers: Content-Type,Access-Token");
header("Access-Control-Expose-Headers: *"); return $next($request);
}}


第二步: 注册路由

注册这个 middleware 到 kernel 中.
分别在 protected $middleware 数组中和 protected $routeMiddleware 数组中
添加我们刚才创建的那个文件class名, 使用 cors 这个别名.

第三步: 设置中间件保护接口

然后在设置它保护 api , 就是$middlewareGroups['api'] 的数组中添加它的别名, 本文中是 'cors'
app/Http/Kernel.php

<?phpnamespace 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,
\App\Http\Middleware\AccessControlAllowOrigin::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',
'cors'
],
]; /**
* 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,
'cors' => \App\Http\Middleware\AccessControlAllowOrigin::class,
];
}


第四步：在路由中添加路由

Route::middleware('cors')->group(function () {
//
});


原文地址：https://segmentfault.com/a/1190000016815828