Laravel 9 + Next.js 购物车Session值始终为Null问题求助

我正在用Laravel 9和Next.js开发电商应用，添加商品到Laravel Session后，获取购物车数据始终返回Null，以下是相关代码和配置：

Next.js 前端代码 #

const addToCart = async (productId: number) => {
    console.log(productId)
    try {
      // 添加商品到购物车
      const rawResponse = await axios.post(`http://localhost:3001/product/add-to-cart/${productId}`);
      // 从Session获取购物车数据
      const cartData = await axios.get(`http://localhost:3001/products/cart`);

    } catch (e) {

    }
  }

Laravel 后端配置 #

路由（web.php） #

Route::post('product/add-to-cart/{id}', [ProductController::class, 'addProductToCart']);

Route::get('products/cart', [ProductController::class, 'getProductsInCart']);

ProductController 代码 #

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Models\Product;

class ProductController extends Controller {
 
    public function addProductToCart(Request $request, $id) {
    
            $product = Product::findOrFail($id);

        $cart = session()->get('cart', []);

        if(isset($cart[$id])) {
            $cart[$id]['quantity']++;
        } else {
            $cart[$id] = [
                "productId"=> $product->id,
                "name" => $product->name,
                "quantity" => 1,
                "price" => $product->price,
            ];
        }

                  
        session()->put('cart', $cart);

        return response()->json(['success' => 'success'], 200);
    }

    public function getProductsInCart(Request $request) {
        $cart = session()->get('cart');
    
        var_dump($cart); // 此处输出为Null

        return $cart;
    }
}

Kernel.php CORS及中间件配置 #

<?php

namespace App\Http;

use Illuminate\Foundation\Http\Kernel as HttpKernel;

class Kernel extends HttpKernel
{
    /**
     * 应用全局HTTP中间件栈
     *
     * 这些中间件会在每个请求时运行
     *
     * @var array<int, class-string|string>
     */
    protected $middleware = [
        \Fruitcake\Cors\HandleCors::class,
        \Illuminate\Session\Middleware\StartSession::class,
        \App\Http\Middleware\TrustProxies::class,
        \Illuminate\Http\Middleware\HandleCors::class,
        \App\Http\Middleware\PreventRequestsDuringMaintenance::class,
        \Illuminate\Foundation\Http\Middleware\ValidatePostSize::class,
        \App\Http\Middleware\TrimStrings::class,
        \Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull::class,
    ];

    /**
     * 应用路由中间件组
     *
     * @var array<string, array<int, class-string|string>>
     */
    protected $middlewareGroups = [
        'web' => [
            \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,
            \Illuminate\Routing\Middleware\SubstituteBindings::class,
        ],

        'api' => [
            \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,
            \Illuminate\Routing\Middleware\SubstituteBindings::class,
        ],
    ];

    /**
     * 应用路由中间件
     *
     * 这些中间件可分配到组或单独使用
     *
     * @var array<string, class-string|string>
     */
    protected $routeMiddleware = [
        'auth' => \App\Http\Middleware\Authenticate::class,
        'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
        'auth.session' => \Illuminate\Session\Middleware\AuthenticateSession::class,
        'cache.headers' => \Illuminate\Http\Middleware\SetCacheHeaders::class,
        'can' => \Illuminate\Auth\Middleware\Authorize::class,
        'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
        'password.confirm' => \Illuminate\Auth\Middleware\RequirePassword::class,
        'signed' => \Illuminate\Routing\Middleware\ValidateSignature::class,
        'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class,
        'verified' => \Illuminate\Auth\Middleware\EnsureEmailIsVerified::class,

        'isAdmin' => \App\Http\Middleware\isAdmin::class,
    ];
}

问题现象 #

调用添加商品接口后，再调用购物车获取接口时，session()->get('cart')返回Null。

排查方向及解决方法 #

1. 跨域请求未携带Cookie #

Next.js的axios请求默认不会携带Cookie，导致两次请求不属于同一个Session。修改前端请求配置，添加withCredentials: true：

const addToCart = async (productId: number) => {
    console.log(productId)
    try {
      // 添加商品时携带Cookie
      const rawResponse = await axios.post(`http://localhost:3001/product/add-to-cart/${productId}`, {}, { withCredentials: true });
      // 获取购物车时携带Cookie
      const cartData = await axios.get(`http://localhost:3001/products/cart`, { withCredentials: true });

    } catch (e) {

    }
  }

同时在Laravel的config/cors.php中开启凭证支持：

'supports_credentials' => true,

2. 中间件顺序及重复配置问题 #

全局中间件中重复添加了HandleCors，且StartSession的位置可能影响Session初始化。建议保留一个Fruitcake的HandleCors，并调整全局中间件顺序：

protected $middleware = [
    \App\Http\Middleware\TrustProxies::class,
    \Fruitcake\Cors\HandleCors::class,
    \App\Http\Middleware\PreventRequestsDuringMaintenance::class,
    \Illuminate\Foundation\Http\Middleware\ValidatePostSize::class,
    \App\Http\Middleware\TrimStrings::class,
    \Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull::class,
];

Session中间件已在web和api组中配置，无需放到全局中间件。

3. Cookie SameSite设置问题 #

如果前后端域名不同，Cookie的SameSite策略会影响携带。在config/session.php中调整：

'same_site' => 'lax',
// 若使用https，可设置为'none'，同时开启secure
// 'same_site' => 'none',
// 'secure' => true,

内容的提问来源于stack exchange，提问作者Loki