files_opds: add FictionBook 2 (.fb2) metadata parser

files_opds/lib/fb2.php

@@ -0,0 +1,217 @@
+<?php
+
+/**
+ * Nextcloud - Files_Opds App
+ *
+ * @author Frank de Lange
+ * @copyright 2016 Frank de Lange
+ *
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ */
+
+namespace OCA\Files_Opds;
+
+/**
+ * FB2 class, a simpleminded read-only fb2 parser intended for metadata extraction
+ */
+class FB2 {
+	protected $file;
+
+	/**
+	 * @brief Constructor
+	 *
+	 * @param string $file path to fb2 file to work on
+	 * @throws Exception if metadata could not be loaded
+	 */
+	public function __construct($file) {
+		// open file
+		$this->file = $file;
+		if (!($this->xml = simplexml_load_file($file))) {
+			throw new \Exception("Failed to read FB2 file");
+		}
+
+		// check for valid XML content 
+		if(!$this->xml) {
+			throw new \Exception("Failed to access XML content");
+		}
+	}
+
+	/**
+	 * @brief file name getter
+	 * @return string filename
+	 */
+	public function file() {
+		return $this->file;
+	}
+
+	/**
+	 * @brief get author(s)
+	 *
+	 * @return array $authors
+	 */
+	public function Authors() {
+		$authors = array();
+		foreach($this->xml->description->{'title-info'}->author as $author) {
+			$authors[] = (string) implode(' ', array_filter(array ($author->{'first-name'} , $author->{'middle-name'} , $author->{'last-name'}, $author->{'nickname'}),function($v){ return (!empty((string) $v));}));
+		}
+		return $authors;
+	}
+
+	/**
+	 * @brief get book title
+	 *
+	 * @return string $title
+	 */
+	public function Title(){
+		return $this->get_string($this->xml->description->{'title-info'}->{'book-title'});
+	}
+
+	/**
+	 * @brief get language
+	 *
+	 * @return string $lang
+	 */
+	public function Language(){
+		return $this->get_string($this->xml->description->{'title-info'}->{'lang'});
+	}
+
+	/**
+	 * @brief get date
+	 *
+	 * @return string $date
+	 */
+	public function Date(){
+		return $this->get_string($this->xml->description->{'document-info'}->{'date'});
+	}
+
+	/**
+	 * @brief get publisher info
+	 *
+	 * @return string $publisher
+	 */
+	public function Publisher(){
+		return $this->get_string($this->xml->description->{'publish-info'}->{'publisher'});
+	}
+
+	/**
+	 * @brief get copyright info
+	 *
+	 * @return string $rights
+	 */
+	public function Copyright(){
+		/* no copyright info in fb2 files */
+		return '';
+	}
+
+	/**
+	 * @brief get description
+	 *
+	 * @return string $description
+	 */
+	public function Description(){
+		$description = null;
+		if (isset($this->xml->description->{'title-info'}->{'annotation'})) {
+			$description = $this->get_innerxml($this->xml->description->{'title-info'}->{'annotation'});
+		}
+
+		return $description;
+	}
+
+	/**
+	 * @brief get ISBN number
+	 *
+	 * @return string $isbn
+	 */
+	public function ISBN(){
+		return $this->get_string($this->xml->description->{'publish-info'}->{'isbn'});
+	}
+
+	/**
+	 * @brief get subjects (aka. tags)
+	 *
+	 * @return array $subjects
+	 */
+	public function Subjects(){
+		$subjects = array();
+		foreach($this->xml->description->{'title-info'}->keywords as $keyword) {
+			$subjects[] =  $keyword->__toString();
+		}
+		return $subjects;
+	}
+
+	/**
+	 * @brief get cover data
+	 *
+	 * Returns an associative array with the following keys:
+	 *
+	 *   mime  - filetype (usually image/jpeg)
+	 *   data  - binary image data
+	 *   found - internal path, or null if no image is set in fb2
+	 * 
+	 * @return array or null
+	 */
+	public function Cover(){
+		$mime = "";
+		$data = null;
+		$path = false;
+
+		if ($this->xml->description->{'title-info'}->coverpage) {
+			$cover_link = isset($this->xml->description->{'title-info'}->coverpage->image->attributes('xlink',true)->href)
+				?  $this->xml->description->{'title-info'}->coverpage->image->attributes('xlink',true)->href->__toString() : "" ;
+			$cover_link = isset($this->xml->description->{'title-info'}->coverpage->image->attributes('l',true)->href)
+				?  $this->xml->description->{'title-info'}->coverpage->image->attributes('l',true)->href->__toString() : $cover_link ;
+
+			$cover_link = trim($cover_link,'#');
+
+			foreach ($this->xml->binary as $binary) {
+				if ($binary['id']->__toString() === $cover_link) {
+					$data = base64_decode($binary->__toString());
+					$mime = $binary['content-type']->__toString();
+					$path = $cover_link;
+					break;
+				}
+			}
+		}
+
+		return (!is_null($data))
+			? array(
+				'mime'  => $mime,
+				'data'  => $data,
+				'found' => $path
+			)
+			: null;
+	}
+
+	/**
+	 * @brief get innerXML as string
+	 * 
+	 * Returns the innerXML for an XML element as string
+	 *
+	 * @return string
+	 */
+	protected function get_innerxml($element) {
+		$innerxml = '';
+		foreach (dom_import_simplexml($element)->childNodes as $child) {
+			$innerxml .= $child->ownerDocument->saveXML($child);
+		}
+	
+		return $innerxml;
+	}
+
+	/**
+	 * @brief get element as string
+	 * 
+	 * Returns simplexml element as string, can cope with null elements
+	 * 
+	 * @return string or null
+	 */
+	protected function get_string($element) {
+		if (!empty($element)) {
+			return $element->__toString();
+		} else {
+			return '';
+		}
+	}
+}
+

files_opds/lib/meta.php

@@ -205,7 +205,6 @@ class Meta
 		return $meta;
 	}
 
-
 	/**
 	 * @brief check epub for metadata
 	 *
@@ -234,6 +233,34 @@ class Meta
 		}
 	}
 
+	/**
+	 * @brief check fb2 for metadata
+	 *
+	 * @param string $path path to fb2
+	 * @param arrayref $meta reference to array of metadata
+	 */
+	public static function fb2($path,&$meta) {
+		$success = false;
+		try {
+			$fb2 = new FB2($path);
+			/* first try ISBN */
+			if(!(($isbn = $fb2->ISBN()) && (Isbn::get($isbn, $meta)))) {
+				/* use FB2 internal metadata instead */
+				$meta['author'] = json_encode($fb2->Authors());
+				$meta['title'] = $fb2->Title();
+				$meta['date'] = $fb2->Date();
+				$meta['publisher'] = $fb2->Publisher();
+				$meta['copyright'] = $fb2->Copyright();
+				$meta['language'] = $fb2->Language();
+				$meta['description'] = strip_tags($fb2->Description());
+				$meta['isbn'] = $fb2->ISBN();
+				$meta['subjects'] = json_encode($fb2->Subjects());
+			}
+		} catch (\Exception $e) {
+			\OCP\Util::writeLog(get_class(), $e->getMessage(), \OCP\Util::ERROR);
+		}
+	}
+
 	/**
 	 * @brief check pdf for metadata
 	 *