Sample plugin for Google Analytics

A common request is to use Google Analytics for Laconica servers. This
plugin will add the correct spell to make Google Analytics work.

plugins/GoogleAnalyticsPlugin.php

+<?php
+/**
+ * Laconica, the distributed open-source microblogging tool
+ *
+ * Plugin to use Google Analytics
+ *
+ * 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  Plugin
+ * @package   Laconica
+ * @author    Evan Prodromou <evan@controlyourself.ca>
+ * @copyright 2008 Control Yourself, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://laconi.ca/
+ */
+
+if (!defined('LACONICA')) {
+    exit(1);
+}
+
+/**
+ * Plugin to use Google Analytics
+ *
+ * This plugin will spoot out the correct JavaScript spell to invoke Google Analytics on a page.
+ *
+ * Note that Google Analytics is not compatible with the Franklin Street Statement; consider using
+ * Pikiw (http://www.pikiw.org/) instead!
+ *
+ * @category Plugin
+ * @package  Laconica
+ * @author   Evan Prodromou <evan@controlyourself.ca>
+ * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link     http://laconi.ca/
+ *
+ * @see      Event
+ */
+
+class GoogleAnalyticsPlugin extends Plugin
+{
+    var $code = null;
+
+    function __construct($code=null)
+    {
+        $this->code = $code;
+        parent::__construct();
+    }
+
+    function onEndShowScripts($action)
+    {
+        $js1 = 'var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");'.
+          'document.write(unescape("%3Cscript src=\'" + gaJsHost + "google-analytics.com/ga.js\' type=\'text/javascript\'%3E%3C/script%3E"));';
+        $js2 = sprintf('try{'.
+                       'var pageTracker = _gat._getTracker("%s");'.
+                       'pageTracker._trackPageview();'.
+                       '} catch(err) {}',
+                       $this->code);
+        $action->elementStart('script', array('type' => 'text/javascript'));
+        $action->raw($js1);
+        $action->elementEnd('script');
+        $action->elementStart('script', array('type' => 'text/javascript'));
+        $action->raw($js2);
+        $action->elementEnd('script');
+    }
+}