浏览器检测：从用户代理确定浏览器和操作系统

<?php
/**
* @version $1.1$
* @package dinke.net
* @copyright © 2008 Dinke.net
* @author Dragan Dinic <dragan@dinke.net>
*/

/**
* Browser Detection class
* contains common static method for
* getting browser version and os
*
* It supports most popular browsers (IE, FF, Safari, Opera, Chrome ...)
* As well as some not so popular (lynx etc.)
* It doesn't recognize bots (like google, yahooo etc)
*
* usage
* <code>
* $browser = Browser_Detection::get_browser($_SERVER['HTTP_USER_AGENT']);
* $os = Browser_Detection::get_os($_SERVER['HTTP_USER_AGENT']);
* </code>
* @access public
*/
class Browser_Detection
{

/**
* Get browsername and version
* @param string user agent
* @return string browser name and version or false if unrecognized
* @static
* @access public
*/
function get_browser($useragent)
{
//check for most popular browsers first
//unfortunately that's ie. We also ignore opera and netscape 8
//because they sometimes send msie agent
if(strpos($useragent,"MSIE") !== false && strpos($useragent,"Opera") === false && strpos($useragent,"Netscape") === false)
{
//deal with IE
$found = preg_match("/MSIE ([0-9]{1}\.[0-9]{1,2})/",$useragent, $mathes);
if($found)
{
return "Internet Explorer " . $mathes[1];
}
}
elseif(strpos($useragent,"Gecko"))
{
//deal with Gecko based

//if firefox
$found = preg_match("/Firefox\/([0-9]{1}\.[0-9]{1}(\.[0-9])?)/",$useragent,$mathes);
if($found)
{
return "Mozilla Firefox " . $mathes[1];
}

//if Netscape (based on gecko)
$found = preg_match("/Netscape\/([0-9]{1}\.[0-9]{1}(\.[0-9])?)/",$useragent,$mathes);
if($found)
{
return "Netscape " . $mathes[1];
}

//check chrome before safari because chrome agent contains both
$found = preg_match("/Chrome\/([^\s]+)/",$useragent, $mathes);
if($found)
{
return "Google Chrome " . $mathes[1];
}

//if Safari (based on gecko)
$found = preg_match("/Safari\/([0-9]{2,3}(\.[0-9])?)/",$useragent, $mathes);
if($found)
{
return "Safari " . $mathes[1];
}

//if Galeon (based on gecko)
$found = preg_match("/Galeon\/([0-9]{1}\.[0-9]{1}(\.[0-9])?)/",$useragent,$mathes);
if($found)
{
return "Galeon " . $mathes[1];
}

//if Konqueror (based on gecko)
$found = preg_match("/Konqueror\/([0-9]{1}\.[0-9]{1}(\.[0-9])?)/",$useragent,$mathes);
if($found)
{
return "Konqueror " . $mathes[1];
}

//no specific Gecko found
//return generic Gecko
return "Gecko based";
}

elseif(strpos($useragent,"Opera") !== false)
{
//deal with Opera
$found = preg_match("/Opera[\/ ]([0-9]{1}\.[0-9]{1}([0-9])?)/",$useragent,$mathes);
if($found)
{
return "Opera " . $mathes[1];
}
}
elseif (strpos($useragent,"Lynx") !== false)
{
//deal with Lynx
$found = preg_match("/Lynx\/([0-9]{1}\.[0-9]{1}(\.[0-9])?)/",$useragent,$mathes);
if($found)
{
return "Lynx " . $mathes[1];
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}

}
elseif (strpos($useragent,"Netscape") !== false)
{
//NN8 with IE string
$found = preg_match("/Netscape\/([0-9]{1}\.[0-9]{1}(\.[0-9])?)/",$useragent,$mathes);
if($found)
{
return "Netscape " . $mathes[1];
}
}
else
{
//unrecognized, this should be less than 1% of browsers (not counting bots like google etc)!
return false;
}
}

/**
* Get browsername and version
* @param string user agent
* @return string os name and version or false in unrecognized os
* @static
* @access public
*/
function get_os($useragent)
{
$useragent = strtolower($useragent);

//check for (aaargh) most popular first
//winxp
if(strpos("$useragent","windows nt 5.1") !== false)
{
return "Windows XP";
}
elseif (strpos("$useragent","windows nt 6.0") !== false)
{
return "Windows Vista";
}
elseif (strpos("$useragent","windows 98") !== false)
{
return "Windows 98";
}
elseif (strpos("$useragent","windows nt 5.0") !== false)
{
return "Windows 2000";
}
elseif (strpos("$useragent","windows nt 5.2") !== false)
{
return "Windows 2003 server";
}
elseif (strpos("$useragent","windows nt 6.0") !== false)
{
return "Windows Vista";
}
elseif (strpos("$useragent","windows nt") !== false)
{
return "Windows NT";
}
elseif (strpos("$useragent","win 9x 4.90") !== false && strpos("$useragent","win me"))
{
return "Windows ME";
}
elseif (strpos("$useragent","win ce") !== false)
{
return "Windows CE";
}
elseif (strpos("$useragent","win 9x 4.90") !== false)
{
return "Windows ME";
}
elseif (strpos("$useragent","iphone") !== false)
{
return "iPhone";
}
elseif (strpos("$useragent","mac os x") !== false)
{
return "Mac OS X";
}
elseif (strpos("$useragent","macintosh") !== false)
{
return "Macintosh";
}
elseif (strpos("$useragent","linux") !== false)
{
return "Linux";
}
elseif (strpos("$useragent","freebsd") !== false)
{
return "Free BSD";
}
elseif (strpos("$useragent","symbian") !== false)
{
return "Symbian";
}
else
{
return false;
}
}
}
?>

<?php

require_once("browser_detection.php");

$browser = Browser_Detection::get_browser($_SERVER['HTTP_USER_AGENT']);
if($browser !== false)
{
echo "Your browser is $browser <br />";
}

$os = Browser_Detection::get_os($_SERVER['HTTP_USER_AGENT']);

if($os !== false)
{
echo "Your OS is $os <br />";
}
?>