[12.x] Allow limiting number of assets to preload (#55618)

* Allow limiting number of assets to preload

* Lint

Author: timacdonald

src/Illuminate/Http/Middleware/AddLinkHeadersForPreloadedAssets.php

@@ -8,18 +8,31 @@
 
 class AddLinkHeadersForPreloadedAssets
 {
+    /**
+     * Configure the middleware.
+     *
+     * @param  int  $limit
+     * @return string
+     */
+    public static function using($limit)
+    {
+        return static::class.':'.$limit;
+    }
+
     /**
      * Handle the incoming request.
      *
      * @param  \Illuminate\Http\Request  $request
      * @param  \Closure  $next
+     * @param  int  $limit
      * @return \Illuminate\Http\Response
      */
-    public function handle($request, $next)
+    public function handle($request, $next, $limit = null)
     {
-        return tap($next($request), function ($response) {
+        return tap($next($request), function ($response) use ($limit) {
             if ($response instanceof Response && Vite::preloadedAssets() !== []) {
                 $response->header('Link', (new Collection(Vite::preloadedAssets()))
+                    ->when($limit, fn ($assets, $limit) => $assets->take($limit))
                     ->map(fn ($attributes, $url) => "<{$url}>; ".implode('; ', $attributes))
                     ->join(', '), false);
             }

tests/Http/Middleware/VitePreloadingTest.php

@@ -106,4 +106,47 @@ public function testItDoesNotOverwriteOtherLinkHeaders()
             $response->headers->all('Link'),
         );
     }
+
+    public function testItCanLimitNumberOfAssetsPreloaded()
+    {
+        $app = new Container;
+        $app->instance(Vite::class, new class extends Vite
+        {
+            protected $preloadedAssets = [
+                'https://laravel.com/first.js' => [
+                    'rel="modulepreload"',
+                    'foo="bar"',
+                ],
+                'https://laravel.com/second.js' => [
+                    'rel="modulepreload"',
+                    'foo="bar"',
+                ],
+                'https://laravel.com/third.js' => [
+                    'rel="modulepreload"',
+                    'foo="bar"',
+                ],
+                'https://laravel.com/fourth.js' => [
+                    'rel="modulepreload"',
+                    'foo="bar"',
+                ],
+            ];
+        });
+        Facade::setFacadeApplication($app);
+
+        $response = (new AddLinkHeadersForPreloadedAssets)->handle(new Request, fn () => new Response('ok'), 2);
+
+        $this->assertSame(
+            [
+                '<https://laravel.com/first.js>; rel="modulepreload"; foo="bar", <https://laravel.com/second.js>; rel="modulepreload"; foo="bar"',
+            ],
+            $response->headers->all('Link'),
+        );
+    }
+
+    public function test_it_can_configure_the_middleware()
+    {
+        $definition = AddLinkHeadersForPreloadedAssets::using(limit: 5);
+
+        $this->assertSame('Illuminate\Http\Middleware\AddLinkHeadersForPreloadedAssets:5', $definition);
+    }
 }