Introduce class `Icinga\Web\Controller\StaticController`

library/Icinga/Web/Controller/StaticController.php

@@ -0,0 +1,77 @@
+<?php
+/* Icinga Web 2 | (c) 2020 Icinga GmbH | GPLv2+ */
+
+namespace Icinga\Web\Controller;
+
+use Icinga\Application\Icinga;
+use Icinga\Web\Request;
+
+class StaticController
+{
+    /**
+     * Handle incoming request
+     *
+     * @param Request $request
+     *
+     * @returns void
+     */
+    public function handle(Request $request)
+    {
+        $app = Icinga::app();
+
+        // +4 because strlen('/lib') === 4
+        $assetPath = ltrim(substr($request->getRequestUri(), strlen($request->getBaseUrl()) + 4), '/');
+
+        $library = null;
+        foreach ($app->getLibraries() as $candidate) {
+            if (substr($assetPath, 0, strlen($candidate->getName())) === $candidate->getName()) {
+                $library = $candidate;
+                $assetPath = ltrim(substr($assetPath, strlen($candidate->getName())), '/');
+                break;
+            }
+        }
+
+        if ($library === null) {
+            $app->getResponse()
+                ->setHttpResponseCode(404);
+
+            return;
+        }
+
+        $assetRoot = $library->getStaticAssetPath();
+        $filePath = $assetRoot . DIRECTORY_SEPARATOR . $assetPath;
+
+        // Doesn't use realpath as it isn't supposed to access files outside asset/static
+        if (! is_readable($filePath) || ! is_file($filePath)) {
+            $app->getResponse()
+                ->setHttpResponseCode(404);
+
+            return;
+        }
+
+        $fileStat = stat($filePath);
+        $eTag = sprintf(
+            '%x-%x-%x',
+            $fileStat['ino'],
+            $fileStat['size'],
+            (float) str_pad($fileStat['mtime'], 16, '0')
+        );
+
+        $app->getResponse()->setHeader(
+            'Cache-Control',
+            'public, max-age=1814400, stale-while-revalidate=604800',
+            true
+        );
+
+        if ($request->getServer('HTTP_IF_NONE_MATCH') === $eTag) {
+            $app->getResponse()
+                ->setHttpResponseCode(304);
+        } else {
+            $app->getResponse()
+                ->setHeader('ETag', $eTag)
+                ->setHeader('Content-Type', mime_content_type($filePath), true)
+                ->setHeader('Last-Modified', gmdate('D, d M Y H:i:s', $fileStat['mtime']) . ' GMT')
+                ->setBody(file_get_contents($filePath));
+        }
+    }
+}