- add rudimentary epub parser for metadata extraction

- add cover images
 - add configurable preview settings (should probably be in core or in a separate app)
 - add some metadata to feed template (file size, type and filename)

files_opds/lib/epub-preview.php

@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * ownCloud - Files_Opds App
+ *
+ * @author Frank de Lange
+ * @copyright 2014 Frank de Lange
+ *
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ */
+
+namespace OC\Preview;
+
+/**
+ * Epub preview - returns cover or null
+ */
+class Epub extends Provider {
+
+        public function getMimeType() {
+                return '/application\/epub\+zip/';
+        }
+
+	public function getThumbnail($path, $maxX, $maxY, $scalingup, $fileview) {
+                //get fileinfo
+                $fileInfo = $fileview->getFileInfo($path);
+                if(!$fileInfo) {
+                        return false;
+                }
+
+                $absPath = $fileview->toTmpFile($path);
+
+		$epub = new \OCA\Files_Opds\Epub($absPath);
+
+		$cover = $epub->Cover();
+
+		if ($cover) {
+
+			$image = new \OC_Image();
+
+			$image->loadFromData($cover['data']);
+		}
+
+		return (($cover !== null) && $image->valid()) ? $image : false;
+        }
+
+}
+