From 0e852def6ae5aa529cca0aef1187152fb5a880be Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@pobox.com>
Date: Thu, 21 Jan 2010 16:42:50 -0800
Subject: XMPP queued output & initial retooling of DB queue manager to support
 non-Notice objects.

Queue handlers for XMPP individual & firehose output now send their XML stanzas
to another output queue instead of connecting directly to the chat server. This
lets us have as many general processing threads as we need, while all actual
XMPP input and output go through a single daemon with a single connection open.

This avoids problems with multiple connected resources:
* multiple windows shown in some chat clients (psi, gajim, kopete)
* extra load on server
* incoming message delivery forwarding issues

Database changes:
* queue_item drops 'notice_id' in favor of a 'frame' blob.
  This is based on Craig Andrews' work branch to generalize queues to take any
  object, but conservatively leaving out the serialization for now.
  Table updater (preserves any existing queued items) in db/rc3to09.sql

Code changes to watch out for:
* Queue handlers should now define a handle() method instead of handle_notice()
* QueueDaemon and XmppDaemon now share common i/o (IoMaster) and respawning
  thread management (RespawningDaemon) infrastructure.
* The polling XmppConfirmManager has been dropped, as the message is queued
  directly when saving IM settings.
* Enable $config['queue']['debug_memory'] to output current memory usage at
  each run through the event loop to watch for memory leaks

To do:
* Adapt XMPP i/o to component connection mode for multi-site support.
* XMPP input can also be broken out to a queue, which would allow the actual
  notice save etc to be handled by general queue threads.
* Make sure there are no problems with simply pushing serialized Notice objects
  to queues.
* Find a way to improve interactive performance of the database-backed queue
  handler; polling is pretty painful to XMPP.
* Possibly redo the way QueueHandlers are injected into a QueueManager. The
  grouping used to split out the XMPP output queue is a bit awkward.
---
 lib/queued_xmpp.php | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 lib/queued_xmpp.php

(limited to 'lib/queued_xmpp.php')

diff --git a/lib/queued_xmpp.php b/lib/queued_xmpp.php
new file mode 100644
index 000000000..4b890c4ca
--- /dev/null
+++ b/lib/queued_xmpp.php
@@ -0,0 +1,117 @@
+<?php
+/**
+ * StatusNet, the distributed open-source microblogging tool
+ *
+ * Queue-mediated proxy class for outgoing XMPP messages.
+ *
+ * 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  Network
+ * @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);
+}
+
+require_once INSTALLDIR . '/lib/jabber.php';
+
+class Queued_XMPP extends XMPPHP_XMPP
+{
+	/**
+	 * Constructor
+	 *
+	 * @param string  $host
+	 * @param integer $port
+	 * @param string  $user
+	 * @param string  $password
+	 * @param string  $resource
+	 * @param string  $server
+	 * @param boolean $printlog
+	 * @param string  $loglevel
+	 */
+	public function __construct($host, $port, $user, $password, $resource, $server = null, $printlog = false, $loglevel = null)
+	{
+		parent::__construct($host, $port, $user, $password, $resource, $server, $printlog, $loglevel);
+		// Normally the fulljid isn't filled out until resource binding time;
+		// we need to save it here since we're not talking to a real server.
+		$this->fulljid = "{$this->basejid}/{$this->resource}";
+    }
+
+    /**
+     * Send a formatted message to the outgoing queue for later forwarding
+     * to a real XMPP connection.
+     *
+     * @param string $msg
+     */
+    public function send($msg, $timeout=NULL)
+    {
+        $qm = QueueManager::get();
+        $qm->enqueue(strval($msg), 'xmppout');
+    }
+
+    /**
+     * Since we'll be getting input through a queue system's run loop,
+     * we'll process one standalone message at a time rather than our
+     * own XMPP message pump.
+     *
+     * @param string $message
+     */
+    public function processMessage($message) {
+       $frame = array_shift($this->frames);
+       xml_parse($this->parser, $frame->body, false);
+    }
+
+    //@{
+    /**
+     * Stream i/o functions disabled; push input through processMessage()
+     */
+    public function connect($timeout = 30, $persistent = false, $sendinit = true)
+    {
+        throw new Exception("Can't connect to server from XMPP queue proxy.");
+    }
+
+    public function disconnect()
+    {
+        throw new Exception("Can't connect to server from XMPP queue proxy.");
+    }
+
+    public function process()
+    {
+        throw new Exception("Can't read stream from XMPP queue proxy.");
+    }
+
+    public function processUntil($event, $timeout=-1)
+    {
+        throw new Exception("Can't read stream from XMPP queue proxy.");
+    }
+
+    public function read()
+    {
+        throw new Exception("Can't read stream from XMPP queue proxy.");
+    }
+
+    public function readyToProcess()
+    {
+        throw new Exception("Can't read stream from XMPP queue proxy.");
+    }
+    //@}
+}
+
-- 
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