如何使用PHP判断用户是否通过手机访问？

直接看代码：

$agent = check_wap();
if( $agent )
{
 header('Location: http://www.nowamagic.net');
 exit;
}

// check if wap 
function check_wap(){
 // 先检查是否为wap代理，准确度高
 if(stristr($_SERVER['HTTP_VIA'],"wap")){
 return true;
 }
 // 检查浏览器是否接受 WML.
 elseif(strpos(strtoupper($_SERVER['HTTP_ACCEPT']),"VND.WAP.WML") > 0){
 return true;
 }
 //检查USER_AGENT
 elseif(preg_match('/(blackberry|configuration\/cldc|hp |hp-|htc |htc_|htc-|iemobile|kindle|midp|mmp|motorola|mobile|nokia|opera mini|opera |Googlebot-Mobile|YahooSeeker\/M1A1-R2D2|android|iphone|ipod|mobi|palm|palmos|pocket|portalmmm|ppc;|smartphone|sonyericsson|sqh|spv|symbian|treo|up.browser|up.link|vodafone|windows ce|xda |xda_)/i', $_SERVER['HTTP_USER_AGENT'])){
 return true; 
 }
 else{
 return false; 
 }
}

PHP框架剥离的判断是否为手机移动终端的函数：

function is_mobile_request()   
{   
  $_SERVER['ALL_HTTP'] = isset($_SERVER['ALL_HTTP']) ? $_SERVER['ALL_HTTP'] : '';   
  $mobile_browser = '0';   
  if(preg_match('/(up.browser|up.link|mmp|symbian|smartphone|midp|wap|phone|iphone|ipad|ipod|android|xoom)/i', strtolower($_SERVER['HTTP_USER_AGENT'])))   
	$mobile_browser++;   
  if((isset($_SERVER['HTTP_ACCEPT'])) and (strpos(strtolower($_SERVER['HTTP_ACCEPT']),'application/vnd.wap.xhtml+xml') !== false))   
	$mobile_browser++;   
  if(isset($_SERVER['HTTP_X_WAP_PROFILE']))   
	$mobile_browser++;   
  if(isset($_SERVER['HTTP_PROFILE']))   
	$mobile_browser++;   
  $mobile_ua = strtolower(substr($_SERVER['HTTP_USER_AGENT'],0,4));   
  $mobile_agents = array(   
		'w3c ','acs-','alav','alca','amoi','audi','avan','benq','bird','blac',   
		'blaz','brew','cell','cldc','cmd-','dang','doco','eric','hipt','inno',   
		'ipaq','java','jigs','kddi','keji','leno','lg-c','lg-d','lg-g','lge-',   
		'maui','maxo','midp','mits','mmef','mobi','mot-','moto','mwbp','nec-',   
		'newt','noki','oper','palm','pana','pant','phil','play','port','prox',   
		'qwap','sage','sams','sany','sch-','sec-','send','seri','sgh-','shar',   
		'sie-','siem','smal','smar','sony','sph-','symb','t-mo','teli','tim-',   
		'tosh','tsm-','upg1','upsi','vk-v','voda','wap-','wapa','wapi','wapp',   
		'wapr','webc','winw','winw','xda','xda-'  
		);   
  if(in_array($mobile_ua, $mobile_agents))   
	$mobile_browser++;   
  if(strpos(strtolower($_SERVER['ALL_HTTP']), 'operamini') !== false)   
	$mobile_browser++;   
  // Pre-final check to reset everything if the user is on Windows   
  if(strpos(strtolower($_SERVER['HTTP_USER_AGENT']), 'windows') !== false)   
	$mobile_browser=0;   
  // But WP7 is also Windows, with a slightly different characteristic   
  if(strpos(strtolower($_SERVER['HTTP_USER_AGENT']), 'windows phone') !== false)   
	$mobile_browser++;   
  if($mobile_browser>0)   
	return true;   
  else 
	return false;   
}