prevent repeated loading attempts of broken feed icons

apply timeout of 10 seconds when loading feed icons
RSS-Bridge · Nov 12, 2023 · 76235cc · 76235cc
1 parent a55ffd9
commit 76235cc
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Showing 2 changed files with 91 additions and 25 deletions.
diff --git a/actions/FeedIconAction.php b/actions/FeedIconAction.php
@@ -11,63 +11,119 @@ public function __construct()
         $this->bridgeFactory = new BridgeFactory();
     }
 
-    public function execute(array $request)
+    public function execute(array $request): void
     {
         $bridgeClassName = $request['bridgeClassName'] ?? null;
 
-        if (!$bridgeClassName) {
+        if (!$bridgeClassName || !class_exists($bridgeClassName)) {
             $this->sendNotFoundResponse();
         }
 
         $cacheKey = $this->buildCacheKey($bridgeClassName);
 
-        if ($cachedImageData = $this->cache->get($cacheKey)) {
-            $mimeType = $this->cache->get($cacheKey . 'mimeType');
-            if ($mimeType) {
-                $this->sendImageResponse($mimeType, $cachedImageData);
-            }
-        }
-
-        $bridge = $this->bridgeFactory->create($bridgeClassName);
-        $image_url = $bridge->getIcon();
+        list(
+            'imageData' => $imageData,
+            'mimeType' => $mimeType
+        ) = $this->readCache($cacheKey);
 
-        if (!filter_var($image_url, FILTER_VALIDATE_URL)) {
+        if ($imageData && $mimeType) {
+            $this->sendImageResponse($mimeType, $imageData);
+        }
+        elseif('' === $imageData && '' === $mimeType) {
+            // empty values means that the image was broken and could not be loaded
             $this->sendNotFoundResponse();
         }
 
-        $image_data = file_get_contents($image_url);
+        $bridge = $this->bridgeFactory->create($bridgeClassName);
+        $imageUrl = $bridge->getIcon();
+
+        $imageUrl = $this->cleanImageUrl($imageUrl);
 
-        if ($image_data === false) {
+        if (!filter_var($imageUrl, FILTER_VALIDATE_URL)) {
+            //store empty values to prevent further attempts to load broken image
+            $this->writeCache($cacheKey, '', '');
             $this->sendNotFoundResponse();
         }
 
-        $image_info = getimagesize($image_url);
-        if ($image_info === false) {
+        list(
+            'imageData' => $imageData,
+            'mimeType' => $mimeType
+        ) = $this->readImageData($imageUrl);
+
+        if (false === $imageData || false === $mimeType) {
+            //store empty values to prevent further attempts to load broken image
+            $this->writeCache($cacheKey, '', '');
             $this->sendNotFoundResponse();
         }
 
-        $mimeType = $image_info['mime'];
-        $this->cache->set($cacheKey . 'mimeType', $mimeType);
-        $this->cache->set($cacheKey, $image_data);
-
-        $this->sendImageResponse($mimeType, $image_data);
+        $this->writeCache($cacheKey, $mimeType, $imageData);
+        $this->sendImageResponse($mimeType, $imageData);
     }
 
-    private function sendNotFoundResponse()
+    private function sendNotFoundResponse(): void
     {
         header('HTTP/1.1 404 Not Found');
         exit;
     }
 
-    private function sendImageResponse($mimeType, $imageData)
+    private function sendImageResponse(string $mimeType, string $imageData): void
     {
         header('Content-Type: ' . $mimeType);
         echo $imageData;
         exit;
     }
 
-    public function buildCacheKey($bridgeClassName): string
+    private function buildCacheKey(string $bridgeClassName): string
     {
         return md5($bridgeClassName . 'icon');
     }
+
+    private function cleanImageUrl(string $imageUrl): string
+    {
+        //negative look behind: replace duplicate slashes in path, but not in protocol part of uri
+        $imageUrl = preg_replace('~(?<!:)//~', '/', $imageUrl);
+        return str_replace(["\r", "\n"], '', $imageUrl);
+    }
+
+    private function writeCache(string $cacheKey, string $mimeType, string $imageData): void
+    {
+        $this->cache->set($cacheKey, ['imageData' => $imageData, 'mimeType' => $mimeType]);
+    }
+
+    private function readCache(string $cacheKey): array
+    {
+        return (array)$this->cache->get($cacheKey);
+    }
+
+    private function readImageData(string $imageUrl): array
+    {
+        $context = stream_context_create([
+            'http' => [
+                'timeout' => 10,
+            ],
+        ]);
+
+        $handle = @fopen($imageUrl, 'r', false, $context);
+
+        if ($handle === false) {
+            return ['imageData' => false, 'mimeType' => false];
+        }
+        $metaData = stream_get_meta_data($handle);
+        $headers = $metaData['wrapper_data'];
+
+        $contentType = false;
+
+        foreach ($headers as $header) {
+            if (stripos($header, 'Content-Type:') === 0) {
+                $contentType = trim(substr($header, 13)); // 13 is the length of "Content-Type:"
+                break;
+            }
+        }
+
+        $imageData = stream_get_contents($handle);
+
+        fclose($handle);
+
+        return ['imageData' => $imageData, 'mimeType' => $contentType];
+    }
 }
diff --git a/lib/BridgeCard.php b/lib/BridgeCard.php
@@ -20,7 +20,7 @@ public static function displayBridgeCard($bridgeClassName, $formats, $isActive =
 
         $uri = $bridge->getURI();
         $name = $bridge->getName();
-        $icon = $_SERVER['PHP_SELF'] . '?action=FeedIcon&bridgeClassName=' . $bridgeClassName;
+        $icon = self::hasBrokenIcon($bridgeClassName) ? '' : $_SERVER['PHP_SELF'] . '?action=FeedIcon&bridgeClassName=' . $bridgeClassName;
         $description = $bridge->getDescription();
         $parameters = $bridge->getParameters();
         if (Configuration::getConfig('proxy', 'url') && Configuration::getConfig('proxy', 'by_bridge')) {
@@ -371,4 +371,14 @@ private static function getCheckboxInput($entry, $id, $name)
         . ' />'
         . PHP_EOL;
     }
+
+    private static function hasBrokenIcon(string $bridgeClassName): bool
+    {
+        $logger = RssBridge::getLogger();
+        $cacheFactory = new CacheFactory($logger);
+        $cache = $cacheFactory->create();
+        $cacheKey = md5($bridgeClassName . 'icon');
+        $cachedImage = (array)$cache->get($cacheKey);
+        return isset($cachedImage['imageData']) && '' === $cachedImage['imageData'] && isset($cachedImage['mimeType']) && '' === $cachedImage['mimeType'];
+    }
 }