Middleware

Introduction

Middleware provide a convenient mechanism for inspecting and filtering HTTP requests entering your application. For example, Laravel includes a middleware that verifies the user of your application is authenticated. If the user is not authenticated, the middleware will redirect the user to your application's login screen. However, if the user is authenticated, the middleware will allow the request to proceed further into the application.

Additional middleware can be written to perform a variety of tasks besides authentication. For example, a logging middleware might log all incoming requests to your application. A variety of middleware are included in Laravel, including middleware for authentication and CSRF protection; however, all user-defined middleware are typically located in your application's app/Http/Middleware directory.

Defining Middleware

To create a new middleware, use the make:middleware Artisan command:

php artisan make:middleware EnsureTokenIsValid

This command will place a new EnsureTokenIsValid class within your app/Http/Middleware directory. In this middleware, we will only allow access to the route if the supplied token input matches a specified value. Otherwise, we will redirect the users back to the /home URI:

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Symfony\Component\HttpFoundation\Response;

class EnsureTokenIsValid
{
    /**
     * Handle an incoming request.
     *
     * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
     */
    public function handle(Request $request, Closure $next): Response
    {
        if ($request->input('token') !== 'my-secret-token') {
            return redirect('/home');
        }

        return $next($request);
    }
}

As you can see, if the given token does not match our secret token, the middleware will return an HTTP redirect to the client; otherwise, the request will be passed further into the application. To pass the request deeper into the application (allowing the middleware to "pass"), you should call the $next callback with the $request.

It's best to envision middleware as a series of "layers" HTTP requests must pass through before they hit your application. Each layer can examine the request and even reject it entirely.

提示

All middleware are resolved via the service container, so you may type-hint any dependencies you need within a middleware's constructor.

Middleware and Responses

Of course, a middleware can perform tasks before or after passing the request deeper into the application. For example, the following middleware would perform some task before the request is handled by the application:

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Symfony\Component\HttpFoundation\Response;

class BeforeMiddleware
{
    public function handle(Request $request, Closure $next): Response
    {
        // Perform action

        return $next($request);
    }
}

However, this middleware would perform its task after the request is handled by the application:

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Symfony\Component\HttpFoundation\Response;

class AfterMiddleware
{
    public function handle(Request $request, Closure $next): Response
    {
        $response = $next($request);

        // Perform action

        return $response;
    }
}

Registering Middleware

Global Middleware

If you want a middleware to run during every HTTP request to your application, you may append it to the global middleware stack in your application's bootstrap/app.php file:

use App\Http\Middleware\EnsureTokenIsValid;

->withMiddleware(function (Middleware $middleware) {
     $middleware->append(EnsureTokenIsValid::class);
})

The $middleware object provided to the withMiddleware closure is an instance of Illuminate\Foundation\Configuration\Middleware and is responsible for managing the middleware assigned to your application's routes. The append method adds the middleware to the end of the list of global middleware. If you would like to add a middleware to the beginning of the list, you should use the prepend method.

Manually Managing Laravel's Default Global Middleware

If you would like to manage Laravel's global middleware stack manually, you may provide Laravel's default stack of global middleware to the use method. Then, you may adjust the default middleware stack as necessary:

->withMiddleware(function (Middleware $middleware) {
    $middleware->use([
        // \Illuminate\Http\Middleware\TrustHosts::class,
        \Illuminate\Http\Middleware\TrustProxies::class,
        \Illuminate\Http\Middleware\HandleCors::class,
        \Illuminate\Foundation\Http\Middleware\PreventRequestsDuringMaintenance::class,
        \Illuminate\Http\Middleware\ValidatePostSize::class,
        \Illuminate\Foundation\Http\Middleware\TrimStrings::class,
        \Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull::class,
    ]);
})

Assigning Middleware to Routes

If you would like to assign middleware to specific routes, you may invoke the middleware method when defining the route:

use App\Http\Middleware\EnsureTokenIsValid;

Route::get('/profile', function () {
    // ...
})->middleware(EnsureTokenIsValid::class);

You may assign multiple middleware to the route by passing an array of middleware names to the middleware method:

Route::get('/', function () {
    // ...
})->middleware([First::class, Second::class]);

Excluding Middleware

When assigning middleware to a group of routes, you may occasionally need to prevent the middleware from being applied to an individual route within the group. You may accomplish this using the withoutMiddleware method:

use App\Http\Middleware\EnsureTokenIsValid;

Route::middleware([EnsureTokenIsValid::class])->group(function () {
    Route::get('/', function () {
        // ...
    });

    Route::get('/profile', function () {
        // ...
    })->withoutMiddleware([EnsureTokenIsValid::class]);
});

You may also exclude a given set of middleware from an entire group of route definitions:

use App\Http\Middleware\EnsureTokenIsValid;

Route::withoutMiddleware([EnsureTokenIsValid::class])->group(function () {
    Route::get('/profile', function () {
        // ...
    });
});

The withoutMiddleware method can only remove route middleware and does not apply to global middleware.

Middleware Groups

Sometimes you may want to group several middleware under a single key to make them easier to assign to routes. You may accomplish this using the appendToGroup method within your application's bootstrap/app.php file:

use App\Http\Middleware\First;
use App\Http\Middleware\Second;

->withMiddleware(function (Middleware $middleware) {
    $middleware->appendToGroup('group-name', [
        First::class,
        Second::class,
    ]);

    $middleware->prependToGroup('group-name', [
        First::class,
        Second::class,
    ]);
})

Middleware groups may be assigned to routes and controller actions using the same syntax as individual middleware:

Route::get('/', function () {
    // ...
})->middleware('group-name');

Route::middleware(['group-name'])->group(function () {
    // ...
});

Laravel's Default Middleware Groups

Laravel includes predefined web and api middleware groups that contain common middleware you may want to apply to your web and API routes. Remember, Laravel automatically applies these middleware groups to the corresponding routes/web.php and routes/api.php files:

The web Middleware Group
Illuminate\Cookie\Middleware\EncryptCookies
Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse
Illuminate\Session\Middleware\StartSession
Illuminate\View\Middleware\ShareErrorsFromSession
Illuminate\Foundation\Http\Middleware\ValidateCsrfToken
Illuminate\Routing\Middleware\SubstituteBindings

The api Middleware Group
Illuminate\Routing\Middleware\SubstituteBindings

If you would like to append or prepend middleware to these groups, you may use the web and api methods within your application's bootstrap/app.php file. The web and api methods are convenient alternatives to the appendToGroup method:

use App\Http\Middleware\EnsureTokenIsValid;
use App\Http\Middleware\EnsureUserIsSubscribed;

->withMiddleware(function (Middleware $middleware) {
    $middleware->web(append: [
        EnsureUserIsSubscribed::class,
    ]);

    $middleware->api(prepend: [
        EnsureTokenIsValid::class,
    ]);
})

You may even replace one of Laravel's default middleware group entries with a custom middleware of your own:

use App\Http\Middleware\StartCustomSession;
use Illuminate\Session\Middleware\StartSession;

$middleware->web(replace: [
    StartSession::class => StartCustomSession::class,
]);

Or, you may remove a middleware entirely:

$middleware->web(remove: [
    StartSession::class,
]);

Manually Managing Laravel's Default Middleware Groups

If you would like to manually manage all of the middleware within Laravel's default web and api middleware groups, you may redefine the groups entirely. The example below will define the web and api middleware groups with their default middleware, allowing you to customize them as necessary:

->withMiddleware(function (Middleware $middleware) {
    $middleware->group('web', [
        \Illuminate\Cookie\Middleware\EncryptCookies::class,
        \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
        \Illuminate\Session\Middleware\StartSession::class,
        \Illuminate\View\Middleware\ShareErrorsFromSession::class,
        \Illuminate\Foundation\Http\Middleware\ValidateCsrfToken::class,
        \Illuminate\Routing\Middleware\SubstituteBindings::class,
        // \Illuminate\Session\Middleware\AuthenticateSession::class,
    ]);

    $middleware->group('api', [
        // \Laravel\Sanctum\Http\Middleware\EnsureFrontendRequestsAreStateful::class,
        // 'throttle:api',
        \Illuminate\Routing\Middleware\SubstituteBindings::class,
    ]);
})

提示

By default, the web and api middleware groups are automatically applied to your application's corresponding routes/web.php and routes/api.php files by the bootstrap/app.php file.

Middleware Aliases

You may assign aliases to middleware in your application's bootstrap/app.php file. Middleware aliases allow you to define a short alias for a given middleware class, which can be especially useful for middleware with long class names:

use App\Http\Middleware\EnsureUserIsSubscribed;

->withMiddleware(function (Middleware $middleware) {
    $middleware->alias([
        'subscribed' => EnsureUserIsSubscribed::class
    ]);
})

Once the middleware alias has been defined in your application's bootstrap/app.php file, you may use the alias when assigning the middleware to routes:

Route::get('/profile', function () {
    // ...
})->middleware('subscribed');

For convenience, some of Laravel's built-in middleware are aliased by default. For example, the auth middleware is an alias for the Illuminate\Auth\Middleware\Authenticate middleware. Below is a list of the default middleware aliases:

Alias	Middleware
auth	Illuminate\Auth\Middleware\Authenticate
auth.basic	Illuminate\Auth\Middleware\AuthenticateWithBasicAuth
auth.session	Illuminate\Session\Middleware\AuthenticateSession
cache.headers	Illuminate\Http\Middleware\SetCacheHeaders
can	Illuminate\Auth\Middleware\Authorize
guest	Illuminate\Auth\Middleware\RedirectIfAuthenticated
password.confirm	Illuminate\Auth\Middleware\RequirePassword
precognitive	Illuminate\Foundation\Http\Middleware\HandlePrecognitiveRequests
signed	Illuminate\Routing\Middleware\ValidateSignature
subscribed	\Spark\Http\Middleware\VerifyBillableIsSubscribed
throttle	Illuminate\Routing\Middleware\ThrottleRequests or Illuminate\Routing\Middleware\ThrottleRequestsWithRedis
verified	Illuminate\Auth\Middleware\EnsureEmailIsVerified

Sorting Middleware

Rarely, you may need your middleware to execute in a specific order but not have control over their order when they are assigned to the route. In these situations, you may specify your middleware priority using the priority method in your application's bootstrap/app.php file:

->withMiddleware(function (Middleware $middleware) {
    $middleware->priority([
        \Illuminate\Foundation\Http\Middleware\HandlePrecognitiveRequests::class,
        \Illuminate\Cookie\Middleware\EncryptCookies::class,
        \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
        \Illuminate\Session\Middleware\StartSession::class,
        \Illuminate\View\Middleware\ShareErrorsFromSession::class,
        \Illuminate\Foundation\Http\Middleware\ValidateCsrfToken::class,
        \Laravel\Sanctum\Http\Middleware\EnsureFrontendRequestsAreStateful::class,
        \Illuminate\Routing\Middleware\ThrottleRequests::class,
        \Illuminate\Routing\Middleware\ThrottleRequestsWithRedis::class,
        \Illuminate\Routing\Middleware\SubstituteBindings::class,
        \Illuminate\Contracts\Auth\Middleware\AuthenticatesRequests::class,
        \Illuminate\Auth\Middleware\Authorize::class,
    ]);
})

Middleware Parameters

Middleware can also receive additional parameters. For example, if your application needs to verify that the authenticated user has a given "role" before performing a given action, you could create an EnsureUserHasRole middleware that receives a role name as an additional argument.

Additional middleware parameters will be passed to the middleware after the $next argument:

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Symfony\Component\HttpFoundation\Response;

class EnsureUserHasRole
{
    /**
     * Handle an incoming request.
     *
     * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
     */
    public function handle(Request $request, Closure $next, string $role): Response
    {
        if (! $request->user()->hasRole($role)) {
            // Redirect...
        }

        return $next($request);
    }

}

Middleware parameters may be specified when defining the route by separating the middleware name and parameters with a ::

Route::put('/post/{id}', function (string $id) {
    // ...
})->middleware('role:editor');

Multiple parameters may be delimited by commas:

Route::put('/post/{id}', function (string $id) {
    // ...
})->middleware('role:editor,publisher');

Terminable Middleware

Sometimes a middleware may need to do some work after the HTTP response has been sent to the browser. If you define a terminate method on your middleware and your web server is using FastCGI, the terminate method will automatically be called after the response is sent to the browser:

<?php

namespace Illuminate\Session\Middleware;

use Closure;
use Illuminate\Http\Request;
use Symfony\Component\HttpFoundation\Response;

class TerminatingMiddleware
{
    /**
     * Handle an incoming request.
     *
     * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
     */
    public function handle(Request $request, Closure $next): Response
    {
        return $next($request);
    }

    /**
     * Handle tasks after the response has been sent to the browser.
     */
    public function terminate(Request $request, Response $response): void
    {
        // ...
    }
}

The terminate method should receive both the request and the response. Once you have defined a terminable middleware, you should add it to the list of routes or global middleware in your application's bootstrap/app.php file.

When calling the terminate method on your middleware, Laravel will resolve a fresh instance of the middleware from the service container. If you would like to use the same middleware instance when the handle and terminate methods are called, register the middleware with the container using the container's singleton method. Typically this should be done in the register method of your AppServiceProvider:

use App\Http\Middleware\TerminatingMiddleware;

/**
 * Register any application services.
 */
public function register(): void
{
    $this->app->singleton(TerminatingMiddleware::class);
}