UnknownUriException added for better error handling

lib/unknownuriexception.php

@@ -0,0 +1,49 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * class for exception thrown when a lookup by URI fails
+ *
+ * PHP version 5
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Exception
+ * @package   GNUsocial
+ * @author    Mikael Nordfeldth <mmn@hethane.se>
+ * @copyright 2014 Free Software Foundation, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
+ * @link      https://www.gnu.org/software/social/
+ */
+
+if (!defined('GNUSOCIAL')) { exit(1); }
+
+class UnknownUriException extends ServerException
+{
+    public $object_uri = null;
+
+    public function __construct($object_uri, $msg=null)
+    {
+        $this->object_uri = $object_uri;
+
+        if ($msg === null) {
+            // TRANS: Exception text shown when no object found with certain URI
+            // TRANS: %s is the URI.
+            $msg = sprintf(_('No object found with URI "%s"'), $this->object_uri);
+            common_debug(__CLASS__ . ': ' . $msg);
+        }
+
+        parent::__construct($msg, 404);
+    }
+}