Use session token protection on oEmbed proxy action for LinkPreview... and commit the file *sigh*

plugins/LinkPreview/linkpreview.js

@@ -54,7 +54,8 @@
                 url: url,
                 format: 'json',
                 maxwidth: oEmbed.width,
-                maxheight: oEmbed.height
+                maxheight: oEmbed.height,
+                token: $('#token').val()
             };
             $.get(oEmbed.api, params, function(data, xhr) {
                 callback(data);

plugins/LinkPreview/oembedproxyaction.php

@@ -0,0 +1,84 @@
+<?php
+/**
+ * StatusNet, the distributed open-source microblogging tool
+ *
+ * StatusNet-only extensions to the Twitter-like API
+ *
+ * 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/>.
+ *
+ * @package   StatusNet
+ * @author    Brion Vibber <brion@status.net>
+ * @copyright 2010 StatusNet, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://status.net/
+ */
+
+if (!defined('STATUSNET') && !defined('LACONICA')) {
+    exit(1);
+}
+
+/**
+ * Oembed proxy implementation
+ *
+ * This class provides an interface for our JS-side code to pull info on
+ * links from other sites, using either native oEmbed, our own custom
+ * handlers, or the oohEmbed.com offsite proxy service as configured.
+ *
+ * @category  oEmbed
+ * @package   StatusNet
+ * @author    Brion Vibber <brion@status.net>
+ * @copyright 2010 StatusNet, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://status.net/
+ */
+
+class OembedproxyAction extends OembedAction
+{
+
+    function handle($args)
+    {
+        // We're not a general oEmbed proxy service; limit to valid sessions.
+        $token = $this->trimmed('token');
+        if (!$token || $token != common_session_token()) {
+            $this->clientError(_('There was a problem with your session token. '.
+                                 'Try again, please.'));
+        }
+
+        $format = $this->arg('format');
+        if ($format && $format != 'json') {
+            throw new ClientException('Invalid format; only JSON supported.');
+        }
+
+        $url = $this->arg('url');
+        if (!common_valid_http_url($url)) {
+            throw new ClientException('Invalid URL.');
+        }
+
+        $params = array();
+        if ($this->arg('maxwidth')) {
+            $params['maxwidth'] = $this->arg('maxwidth');
+        }
+        if ($this->arg('maxheight')) {
+            $params['maxheight'] = $this->arg('maxheight');
+        }
+
+        $data = oEmbedHelper::getObject($url, $params);
+
+        $this->init_document('json');
+        print json_encode($data);
+    }
+
+}