add DiskCache.getUrl() and use it in a bunch of places

classes/article.php

@@ -676,7 +676,7 @@ class Article extends Handler_Protected {
 		while ($line = $sth->fetch()) {
 
 			if (file_exists(CACHE_DIR . '/images/' . sha1($line["content_url"]))) {
-				$line["content_url"] = get_self_url_prefix() . '/public.php?op=cached_url&hash=' . sha1($line["content_url"]);
+				$line["content_url"] = DiskCache::getUrl(sha1($line["content_url"]));
 			}
 
 			array_push($rv, $line);

classes/diskcache.php

@@ -56,4 +56,8 @@ class DiskCache {
 	public function send($filename) {
 		return send_local_file($this->getFullPath($filename));
 	}
+
+	static public function getUrl($filename) {
+		return get_self_url_prefix() . "/public.php?op=cached_url&file=" . $filename;
+	}
 }

classes/handler/public.php

@@ -1202,7 +1202,7 @@ class Handler_Public extends Handler {
 	}
 
 	function cached_url() {
-		@$req_filename = basename($_GET['hash']);
+		@$req_filename = basename($_GET['file']);
 
 		// we don't need an extension to find the file, hash is a complete URL
 		$hash = preg_replace("/\.[^\.]*$/", "", $req_filename);

include/functions.php

@@ -1258,20 +1258,7 @@
 
 				if (file_exists($cached_filename)) {
 
-					// this is strictly cosmetic
-					if ($entry->tagName == 'img') {
-						$suffix = ".png";
-					} else if ($entry->parentNode && $entry->parentNode->tagName == "picture") {
-						$suffix = ".png";
-					} else if ($entry->parentNode && $entry->parentNode->tagName == "video") {
-						$suffix = ".mp4";
-					} else if ($entry->parentNode && $entry->parentNode->tagName == "audio") {
-						$suffix = ".ogg";
-					} else {
-						$suffix = "";
-					}
-
-					$src = get_self_url_prefix() . '/public.php?op=cached_url&hash=' . sha1($src) . $suffix;
+					$src = DiskCache::getUrl(sha1($src));
 
 					if ($entry->hasAttribute('poster'))
 						$entry->setAttribute('poster', $src);