public function handle($request, Closure $next)
{
    // 排除特定路由
    if ($request->routeIs('home') || $request->is('api/*')) {
        return $next($request);
    }

    // 域名检查逻辑
    $isTargetDomain = $request->getHost() === 'www.a.com';
    $request->attributes->set('is_target_domain', $isTargetDomain);

    return $next($request);
}    

Route::get('/home', [HomeController::class, 'index'])->withoutMiddleware([CheckDomain::class]);