1 files changed, 76 insertions, 1 deletions

diff --git a/apps/files_sharing/lib/external/storage.php b/apps/files_sharing/lib/external/storage.php
index 454196f15ae..be3f367c383 100644
--- a/apps/files_sharing/lib/external/storage.php
+++ b/apps/files_sharing/lib/external/storage.php
@@ -10,7 +10,11 @@ namespace OCA\Files_Sharing\External;
 
 use OC\Files\Filesystem;
 use OC\Files\Storage\DAV;
+use OC\ForbiddenException;
 use OCA\Files_Sharing\ISharedStorage;
+use OCP\Files\NotFoundException;
+use OCP\Files\StorageInvalidException;
+use OCP\Files\StorageNotAvailableException;
 
 class Storage extends DAV implements ISharedStorage {
 	/**
@@ -108,6 +112,8 @@ class Storage extends DAV implements ISharedStorage {
 	 *
 	 * @param string $path
 	 * @param int $time
+	 * @throws \OCP\Files\StorageNotAvailableException
+	 * @throws \OCP\Files\StorageInvalidException
 	 * @return bool
 	 */
 	public function hasUpdated($path, $time) {
@@ -117,6 +123,75 @@ class Storage extends DAV implements ISharedStorage {
 			return false;
 		}
 		$this->updateChecked = true;
-		return parent::hasUpdated('', $time);
+		try {
+			return parent::hasUpdated('', $time);
+		} catch (StorageNotAvailableException $e) {
+			// see if we can find out why the share is unavailable\
+			try {
+				$this->getShareInfo();
+			} catch (NotFoundException $shareException) {
+				// a 404 can either mean that the share no longer exists or there is no ownCloud on the remote
+				if ($this->testRemote()) {
+					// valid ownCloud instance means that the public share no longer exists
+					// since this is permanent (re-sharing the file will create a new token)
+					// we mark the storage as invalid
+					throw new StorageInvalidException();
+				} else {
+					// ownCloud instance is gone, likely to be a temporary server configuration error
+					throw $e;
+				}
+			} catch(\Exception $shareException) {
+				// todo, maybe handle 403 better and ask the user for a new password
+				throw $e;
+			}
+			throw $e;
+		}
+	}
+
+	/**
+	 * check if the configured remote is a valid ownCloud instance
+	 *
+	 * @return bool
+	 */
+	protected function testRemote() {
+		try {
+			$result = file_get_contents($this->remote . '/status.php');
+			$data = json_decode($result);
+			return is_object($data) and !empty($data->version);
+		} catch (\Exception $e) {
+			return false;
+		}
+	}
+
+	public function getShareInfo() {
+		$remote = $this->getRemote();
+		$token = $this->getToken();
+		$password = $this->getPassword();
+		$url = $remote . '/index.php/apps/files_sharing/shareinfo?t=' . $token;
+
+		$ch = curl_init();
+
+		curl_setopt($ch, CURLOPT_URL, $url);
+		curl_setopt($ch, CURLOPT_POST, 1);
+		curl_setopt($ch, CURLOPT_POSTFIELDS,
+			http_build_query(array('password' => $password)));
+		curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+
+		$result = curl_exec($ch);
+
+		$status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
+		curl_close($ch);
+
+		switch ($status) {
+			case 401:
+			case 403:
+				throw new ForbiddenException();
+			case 404:
+				throw new NotFoundException();
+			case 500:
+				throw new \Exception();
+		}
+
+		return json_decode($result, true);
 	}
 }