1 files changed, 138 insertions, 10 deletions

diff --git a/Zotlabs/Thumbs/Epubthumb.php b/Zotlabs/Thumbs/Epubthumb.php
index b50583e30..af372e85c 100644
--- a/Zotlabs/Thumbs/Epubthumb.php
+++ b/Zotlabs/Thumbs/Epubthumb.php
@@ -2,8 +2,11 @@
 
 namespace Zotlabs\Thumbs;
 
-use SebLucas\EPubMeta\EPub;
+use DOMDocument;
+use DOMElement;
+use DOMXPath;
 use GdImage;
+use ZipArchive;
 
 /**
  * Thumbnail creation for epub files.
@@ -24,20 +27,21 @@ class Epubthumb {
 	 * Create the thumbnail if the Epub has a cover.
 	 *
 	 * @param array $attach
-	 * @param number $preview_style unused
-	 * @param number $height (optional) default 300
-	 * @param number $width (optional) default 300
+	 * @param int $preview_style unused
+	 * @param int $height (optional) default 300
+	 * @param int $width (optional) default 300
 	 *
 	 * @SuppressWarnings(PHPMD.UnusedFormalParameter)
+	 * phpcs:disable Generic.CodeAnalysis.UnusedFunctionParameter.FoundBeforeLastUsed
 	 */
-	function Thumb($attach, $preview_style, $height = 300, $width = 300) {
+	function Thumb($attach, $preview_style, $height = 300, $width = 300): void {
 
 		$file = dbunescbin($attach['content']);
 		if (!$file) {
 			return;
 		}
 
-		$image = $this->getCover($file);
+		$image = $this->getCoverFromEpub($file);
 
 		if ($image) {
 			$srcwidth = imagesx($image);
@@ -56,15 +60,139 @@ class Epubthumb {
 		}
 	}
 
-	private function getCover(string $filename): GdImage|false {
-		$epub = new EPub($filename);
-		$cover = $epub->getCover();
+	/**
+	 * Fetch the cover from the epub archive, if it's present.
+	 *
+	 * There's a few limitations here: This will only work if the cover
+	 * is a raster image of a supported format. SVG does not work, neither
+	 * will other schemes sometimes used for cover/front page.
+	 *
+	 * @param string $filename	The local filename of the epub archive.
+	 *
+	 * @return GdImage|false	If a cover is found, it is returned as a
+	 *	GdImage object. Otherwise return false.
+	 */
+	private function getCoverFromEpub(string $filename): GdImage|false {
+		$epub = new ZipArchive();
+		$rc = $epub->open($filename, ZipArchive::RDONLY);
+
+		if ($rc !== true) {
+			logger("Error opening file '{$filename}': rc = ${rc}.", LOGGER_DEBUG, LOG_DEBUG);
+			return false;
+		}
+
+		$cover = false;
+		$cover_name = $this->parseEpub($epub);
+		if ($cover_name !== false) {
+			$cover = $epub->getFromName($cover_name);
+			if ($cover === false) {
+				logger("File '{$cover_name}' not found in EPUB.", LOGGER_DEBUG, LOG_DEBUG);
+			}
+		}
+
+		$epub->close();
 
-		if (! empty($cover)) {
+		if ($cover !== false && !empty($cover)) {
 			return imagecreatefromstring($cover);
 		} else {
 			return false;
 		}
 	}
+
+	/**
+	 * Parse the epub to find the path of the cover image.
+	 *
+	 * @param ZipArchive $epub	An opened epub ZipArchive.
+	 *
+	 * @return string|false		The path to the cover image or false.
+	 */
+	private function parseEpub(ZipArchive $epub): string|false {
+		$packagePath = $this->getEpubPackagePath($epub);
+		if ($packagePath !== false) {
+			$package = $epub->getFromName($packagePath);
+			if ($package === false || empty($package)) {
+				logger("Package file '${packagePath}' not found in EPUB", LOGGER_DEBUG, LOG_DEBUG);
+				return false;
+			}
+
+			$domdoc = new DOMDocument();
+			$domdoc->loadXML($package);
+			$xpath = new DOMXPath($domdoc);
+			$xpath->registerNamespace("n", "http://www.idpf.org/2007/opf");
+			$nodes = $xpath->query('/n:package/n:manifest/n:item[@properties="cover-image"]');
+
+			if ($nodes->count() === 0) {
+				logger('No cover found in EPUB manifest.', LOGGER_DEBUG, LOG_DEBUG);
+				return false;
+			}
+
+			$node = $nodes->item(0);
+			if ($node === null) {
+				logger('No nodes in non-empty node list?', LOGGER_DEBUG, LOG_DEBUG);
+				return false;
+			}
+
+			if (is_a($node, DOMElement::class)) {
+				// The URL's in the package file is relative to the subdirectory
+				// within the epub archive where it is located. See
+				// https://www.w3.org/TR/epub-33/#sec-parsing-urls-metainf
+				return dirname($packagePath) . '/' . $node->getAttribute('href');
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * Locate the package file within the epub.
+	 *
+	 * The package file in an epub archive contains the manifest
+	 * that again may contain a reference to the cover for the
+	 * epub.
+	 *
+	 * @param ZipArchive $epub	An opened epub archive.
+	 *
+	 * @return string|false		The full pathname of the package file or false.
+	 */
+	private function getEpubPackagePath(ZipArchive $epub): string|false {
+		//
+		// The only mandatory known file within the archive is the
+		// container file, so we fetch it to find the reference to
+		// the package file.
+		//
+		// See: https://www.w3.org/TR/epub-33/#sec-container-metainf
+		//
+		$container = $epub->getFromName('META-INF/container.xml');
+
+		if ($container === false || empty($container)) {
+			logger('No container in archive, probably not an EPUB.', LOGGER_DEBUG, LOG_DEBUG);
+			return false;
+		}
+
+		$domdoc = new DOMDocument();
+		$domdoc->loadXML($container);
+		$nodes = $domdoc->getElementsByTagName('rootfile');
+
+		if ($nodes->count() == 0) {
+			logger('EPUB rootfile not found, is this an epub?', LOGGER_DEBUG, LOG_DEBUG);
+			return false;
+		}
+
+		$packageNode = $nodes->item(0);
+		if ($packageNode === null || !is_a($packageNode, DOMElement::class)) {
+			logger('EPUB rootfile element missing or invalid.', LOGGER_DEBUG, LOG_DEBUG);
+			return false;
+		}
+
+		$packagePath = $packageNode->getAttribute('full-path');
+		$packageMediaType = $packageNode->getAttribute('media-type');
+
+		if (empty($packagePath) || $packageMediaType !== 'application/oebps-package+xml') {
+			logger('EPUB package path missing or incorrect media type.', LOGGER_DEBUG, LOG_DEBUG);
+			return false;
+		}
+
+		return $packagePath;
+	}
 }