From 82f2c910052219e65be61b2be1e4ee5420080bf3 Mon Sep 17 00:00:00 2001
From: Ralf Becker <ralfbecker@outdoor-training.de>
Date: Wed, 15 Feb 2012 21:32:45 +0000
Subject: [PATCH] Ajax log file viewer (tail -f)

---
 phpgwapi/inc/class.egw_tail.inc.php | 151 ++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 phpgwapi/inc/class.egw_tail.inc.php

diff --git a/phpgwapi/inc/class.egw_tail.inc.php b/phpgwapi/inc/class.egw_tail.inc.php
new file mode 100644
index 0000000000..87c190acbd
--- /dev/null
+++ b/phpgwapi/inc/class.egw_tail.inc.php
@@ -0,0 +1,151 @@
+<?php
+/**
+ * EGroupware - Ajax log file viewer (tail -f)
+ *
+ * @link http://www.egroupware.org
+ * @author Ralf Becker <RalfBecker@outdoor-training.de>
+ * @copyright 2012 by RalfBecker@outdoor-training.de
+ * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
+ * @package etemplate
+ * @subpackage api
+ * @version $Id$
+ */
+
+/**
+ * Ajax log file viewer (tail -f)
+ *
+ * To not allow to view arbitrary files, allowed filenames are stored in the session.
+ * Class fetches log-file periodically in chunks for 8k.
+ * If fetch returns no new content next request will be in 2s, otherwise in 200ms.
+ * As logfiles can be quiet huge, we display at max the last 32k of it!
+ *
+ * Example usage:
+ *
+ * $error_log = new egw_tail('/var/log/apache2/error_log');
+ * echo $error_log->show();
+ *
+ * Strongly prefered for security reasons is to use a path relative to EGroupware's files_dir,
+ * eg. new egw_tail('groupdav/somelog')!
+ */
+class egw_tail
+{
+	/**
+	 * Maximum size of single ajax request
+	 *
+	 * Currently also maximum size / 4 of displayed logfile content!
+	 */
+	const MAX_CHUNK_SIZE = 8192;
+
+	/**
+	 * Contains allowed filenames to display, we can NOT allow to display arbitrary files!
+	 *
+	 * @param array
+	 */
+	protected $filenames;
+
+	/**
+	 * Filename class is instanciated to view, set by constructor
+	 *
+	 * @param string
+	 */
+	protected $filename;
+
+	/**
+	 * Constructor
+	 *
+	 * @param string $filename=null if not starting with as slash relative to EGw files dir (this is strongly prefered for security reasons)
+	 */
+	public function __construct($filename=null)
+	{
+		$this->filenames =& egw_cache::getSession('phpgwapi', __CLASS__);
+
+		if ($filename)
+		{
+			$this->filename = $filename;
+
+			if (!in_array($filename,$this->filenames)) $this->filenames[] = $filename;
+		}
+	}
+
+	/**
+	 * Ajax callback to load next chunk of log-file
+	 *
+	 * @param string $filename
+	 * @param int $start=0 last position in log-file
+	 */
+	public function ajax_chunk($filename,$start=0)
+	{
+		if (!in_array($filename,$this->filenames))
+		{
+			throw new egw_exception_wrong_parameter("Not allowed to view '$filename'!");
+		}
+		if ($filename[0] != '/') $filename = $GLOBALS['egw_info']['server']['files_dir'].'/'.$filename;
+
+		if (!$start || $start < 0)
+		{
+			$start = filesize($filename) - 4*self::MAX_CHUNK_SIZE;
+			if ($start < 0) $start = 0;
+		}
+		$content = file_get_contents($filename, false, null, $start, self::MAX_CHUNK_SIZE);
+		$length = bytes($content);
+
+		$response = egw_json_response::get();
+		$response->data(array(	// send all responses as data
+			'next' => $start + $length,
+			'length' => $length,
+			'content' => $content,
+		));
+	}
+
+	/**
+	 * Return html & javascript for logviewer
+	 *
+	 * @param string $id='log'
+	 * @return string
+	 */
+	public function show($id='log')
+	{
+		if (!isset($this->filename))
+		{
+			throw new egw_exception_wrong_parameter("Must be instanciated with filename!");
+		}
+		return '
+<script type="text/javascript">
+var '.$id.'_tail_start = 0;
+function refresh_'.$id.'()
+{
+	var ajax = new egw_json_request("home.egw_tail.ajax_chunk",["'.$this->filename.'",'.$id.'_tail_start]);
+	ajax.sendRequest(true,function(_data) {
+		if (_data.length) {
+			'.$id.'_tail_start = _data.next;
+			var log = $j("#'.$id.'").append(_data.content.replace(/</g,"&lt;"));
+			log.animate({ scrollTop: log.attr("scrollHeight") - log.height() + 20 }, 500);
+		}
+		window.setTimeout(refresh_'.$id.',_data.length?200:2000);
+	});
+}
+$j(document).ready(function()
+{
+	var log = $j("#'.$id.'");
+	log.width(log.width());
+	refresh_'.$id.'();
+});
+</script>
+<pre class="tail" id="'.$id.'" style="width: 100%; border: 2px groove silver; height: 480px; overflow: auto;"></pre>';
+	}
+}
+
+// some testcode, if this file is called via it's URL
+if (isset($_SERVER['SCRIPT_FILENAME']) && $_SERVER['SCRIPT_FILENAME'] == __FILE__)
+{
+	$GLOBALS['egw_info'] = array(
+		'flags' => array(
+			'currentapp' => 'admin',
+		),
+	);
+	include_once '../../header.inc.php';
+
+	$error_log = new egw_tail($file='/opt/local/apache2/logs/error_log');
+	echo "<h3>$file</h3>\n";
+	echo $error_log->show();
+}
\ No newline at end of file