Fix around bugs of ownCloud Android app

README.md

@@ -35,6 +35,7 @@ It has been tested with:
 * ownCloud Desktop 2.5.1 and 2.11.1 (Debian)
 * NextCloud Desktop 3.1.1 and 3.6.0 (Debian)
 * NextCloud Android app 3.21.0 (F-Droid)
+* ownCloud Android app 2.21.2 (F-Droid)
 * [NextCloud CLI client](https://docs.nextcloud.com/desktop/3.5/advancedusage.html) 3.1.1 (Debian) *-- Note: make sure to pass options before parameters.*
 
 The following NextCloud specific features are supported:

lib/KaraDAV/Storage.php

@@ -93,9 +93,11 @@ class Storage extends AbstractStorage
 
 		switch ($name) {
 			case 'DAV::getcontentlength':
-				return is_dir($target) ? 0 : filesize($target);
+				return is_dir($target) ? null : filesize($target);
 			case 'DAV::getcontenttype':
-				return mime_content_type($target);
+				// ownCloud app crashes if mimetype is provided for a directory
+				// https://github.com/owncloud/android/issues/3768
+				return is_dir($target) ? null : mime_content_type($target);
 			case 'DAV::resourcetype':
 				return is_dir($target) ? 'collection' : '';
 			case 'DAV::getlastmodified':
@@ -127,11 +129,24 @@ class Storage extends AbstractStorage
 			case 'DAV::lastaccessed':
 				return new \DateTime('@' . fileatime($target));
 			case 'DAV::creationdate':
+				// The ownCloud Android app doesn't like formatted dates, it makes it crash.
+				if (false !== stripos($_SERVER['HTTP_USER_AGENT'] ?? '', 'owncloud')) {
+					return filectime($target);
+				}
+
 				return new \DateTime('@' . filectime($target));
+			case WebDAV::PROP_DIGEST_MD5:
+				if (!is_file($target)) {
+					return null;
+				}
+
+				return md5_file($target);
 			// NextCloud stuff
 			case Nextcloud::PROP_NC_HAS_PREVIEW:
 			case Nextcloud::PROP_NC_IS_ENCRYPTED:
 				return 'false';
+			case NextCloud::PROP_OC_SHARETYPES:
+				return WebDAV::EMPTY_PROP_VALUE;
 			case Nextcloud::PROP_NC_RICH_WORKSPACE:
 				if (!is_dir($target)) {
 					return '';
@@ -151,6 +166,11 @@ class Storage extends AbstractStorage
 				return NextCloud::getDirectID($username, $uri);
 			case Nextcloud::PROP_OC_PERMISSIONS:
 				return implode('', [NextCloud::PERM_READ, NextCloud::PERM_WRITE, NextCloud::PERM_CREATE, NextCloud::PERM_DELETE, NextCloud::PERM_RENAME_MOVE]);
+			case 'DAV::quota-available-bytes':
+				return null;
+				return -3;
+			case 'DAV::quota-used-bytes':
+				return null;
 			case Nextcloud::PROP_OC_SIZE:
 				if (is_dir($target)) {
 					return self::getDirectorySize($target);

lib/KaraDAV/WebDAV.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace KaraDAV;
+
+use KD2\WebDAV\Server as WebDAV_Server;
+
+class WebDAV extends WebDAV_Server
+{
+	protected function html_directory(string $uri, iterable $list, array $strings = self::LANGUAGE_STRINGS): ?string
+	{
+		$out = parent::html_directory($uri, $list, $strings);
+
+		if (null !== $out) {
+			$out = str_replace('</head>', sprintf('<link rel="stylesheet" type="text/css" href="%sfiles.css" /></head>', WWW_URL), $out);
+			$out = str_replace('</body>', sprintf('<script type="text/javascript" src="%sfiles.js"></script></body>', WWW_URL), $out);
+		}
+
+		return $out;
+	}
+}