rework image caching to work without permanent article content rewriting (refs #582)

image.php

@@ -4,14 +4,35 @@
 
 	require_once "config.php";
 
-	$url = base64_decode($_GET['url']);
+	// backwards compatible wrapper for old-style image caching
+	/* if (isset($_GET['url'])) {
+		$url = base64_decode($_GET['url']);
 
-	$filename = CACHE_DIR . '/images/' . sha1($url) . '.png';
+		$filename = CACHE_DIR . '/images/' . sha1($url) . '.png';
 
-	if (file_exists($filename)) {
-		header("Content-type: image/png");
-		echo file_get_contents($filename);
-	} else {
-		header("Location: $url");
+		if (file_exists($filename)) {
+			header("Content-type: image/png");
+			echo file_get_contents($filename);
+		} else {
+			header("Location: $url");
+		}
+
+		return;
+	} */
+
+	@$hash = basename($_GET['hash']);
+
+	if ($hash) {
+
+		$filename = CACHE_DIR . '/images/' . $hash . '.png';
+
+		if (file_exists($filename)) {
+			header("Content-type: image/png");
+			echo file_get_contents($filename);
+		} else {
+			header($_SERVER["SERVER_PROTOCOL"]." 404 Not Found");
+			echo "File not found.";
+		}
 	}
+
 ?>

include/functions.php

@@ -2590,10 +2590,17 @@
 					$entry->setAttribute('href',
 						rewrite_relative_url($site_url, $entry->getAttribute('href')));
 
-				if ($entry->hasAttribute('src'))
-					if (preg_match('/^image.php\?i=[a-z0-9]+$/', $entry->getAttribute('src')) == 0)
-						$entry->setAttribute('src',
-							rewrite_relative_url($site_url, $entry->getAttribute('src')));
+				if ($entry->hasAttribute('src')) {
+					$src = rewrite_relative_url($site_url, $entry->getAttribute('src'));
+
+					$cached_filename = CACHE_DIR . '/images/' . sha1($src) . '.png';
+
+					if (file_exists($cached_filename)) {
+						$src = SELF_URL_PATH . '/image.php?hash=' . sha1($src);
+					}
+
+					$entry->setAttribute('src', $src);
+				}
 			}
 
 			if (strtolower($entry->nodeName) == "a") {

include/rssfuncs.php

@@ -581,7 +581,7 @@
 				}
 
 				if ($cache_images && is_writable(CACHE_DIR . '/images'))
-					$entry_content = cache_images($entry_content, $site_url, $debug_enabled);
+					cache_images($entry_content, $site_url, $debug_enabled);
 
 				$entry_content = db_escape_string($entry_content, false);