1 files changed, 114 insertions, 0 deletions
diff --git a/apps/files_sharing/lib/helper.php b/apps/files_sharing/lib/helper.php
new file mode 100644
index 00000000000..b602fe3599d
--- /dev/null
+++ b/apps/files_sharing/lib/helper.php
@@ -0,0 +1,114 @@
+<?php
+
+namespace OCA\Files_Sharing;
+
+class Helper {
+
+	/**
+	 * Sets up the filesystem and user for public sharing
+	 * @param string $token string share token
+	 * @param string $relativePath optional path relative to the share
+	 * @param string $password optional password
+	 */
+	public static function setupFromToken($token, $relativePath = null, $password = null) {
+		\OC_User::setIncognitoMode(true);
+
+		$linkItem = \OCP\Share::getShareByToken($token);
+		if($linkItem === false || ($linkItem['item_type'] !== 'file' && $linkItem['item_type'] !== 'folder')) {
+			\OC_Response::setStatus(404);
+			\OC_Log::write('core-preview', 'Passed token parameter is not valid', \OC_Log::DEBUG);
+			exit;
+		}
+
+		if(!isset($linkItem['uid_owner']) || !isset($linkItem['file_source'])) {
+			\OC_Response::setStatus(500);
+			\OC_Log::write('core-preview', 'Passed token seems to be valid, but it does not contain all necessary information . ("' . $token . '")', \OC_Log::WARN);
+			exit;
+		}
+
+		$type = $linkItem['item_type'];
+		$fileSource = $linkItem['file_source'];
+		$shareOwner = $linkItem['uid_owner'];
+		$rootLinkItem = \OCP\Share::resolveReShare($linkItem);
+		$path = null;
+		if (isset($rootLinkItem['uid_owner'])) {
+			\OCP\JSON::checkUserExists($rootLinkItem['uid_owner']);
+			\OC_Util::tearDownFS();
+			\OC_Util::setupFS($rootLinkItem['uid_owner']);
+			$path = \OC\Files\Filesystem::getPath($linkItem['file_source']);
+		}
+
+		if ($path === null) {
+			\OCP\Util::writeLog('share', 'could not resolve linkItem', \OCP\Util::DEBUG);
+			\OC_Response::setStatus(404);
+			\OCP\JSON::error(array('success' => false));
+			exit();
+		}
+
+		if (!isset($linkItem['item_type'])) {
+			\OCP\Util::writeLog('share', 'No item type set for share id: ' . $linkItem['id'], \OCP\Util::ERROR);
+			\OC_Response::setStatus(404);
+			\OCP\JSON::error(array('success' => false));
+			exit();
+		}
+
+		if (isset($linkItem['share_with'])) {
+			if (!self::authenticate($linkItem, $password)) {
+				\OC_Response::setStatus(403);
+				\OCP\JSON::error(array('success' => false));
+				exit();
+			}
+		}
+
+		$basePath = $path;
+		$rootName = basename($path);
+
+		if ($relativePath !== null && \OC\Files\Filesystem::isReadable($basePath . $relativePath)) {
+			$path .= \OC\Files\Filesystem::normalizePath($relativePath);
+		}
+
+		return array(
+			'linkItem' => $linkItem,
+			'basePath' => $basePath,
+			'realPath' => $path
+		);
+	}
+
+	/**
+	 * Authenticate link item with the given password
+	 * or with the session if no password was given.
+	 * @param array $linkItem link item array
+	 * @param string $password optional password
+	 *
+	 * @return true if authorized, false otherwise
+	 */
+	public static function authenticate($linkItem, $password) {
+		if ($password !== null) {
+			if ($linkItem['share_type'] == \OCP\Share::SHARE_TYPE_LINK) {
+				// Check Password
+				$forcePortable = (CRYPT_BLOWFISH != 1);
+				$hasher = new PasswordHash(8, $forcePortable);
+				if (!($hasher->CheckPassword($password.OC_Config::getValue('passwordsalt', ''),
+											 $linkItem['share_with']))) {
+					return false;
+				} else {
+					// Save item id in session for future requests
+					\OC::$session->set('public_link_authenticated', $linkItem['id']);
+				}
+			} else {
+				\OCP\Util::writeLog('share', 'Unknown share type '.$linkItem['share_type']
+					.' for share id '.$linkItem['id'], \OCP\Util::ERROR);
+				return false;
+			}
+
+		}
+		else {
+			// not authenticated ?
+			if ( ! \OC::$session->exists('public_link_authenticated')
+				|| \OC::$session->get('public_link_authenticated') !== $linkItem['id']) {
+				return false;
+			}
+		}
+		return true;
+	}
+}