PHP判断设备访问来源

/**

• 判断用户请求设备是否是移动设备

• @return bool
  */
  function isMobile() {

  //如果有HTTP_X_WAP_PROFILE则一定是移动设备
  if (isset($_SERVER[‘HTTP_X_WAP_PROFILE’])) {
  return true;
  }

  //如果via信息含有wap则一定是移动设备,部分服务商会屏蔽该信息
  if (isset(KaTeX parse error: Expected 'EOF', got '&' at position 22: …R['HTTP_VIA']) &̲& stristr(_SERVER[‘HTTP_VIA’], ‘wap’)) {
  return true;
  }

  //野蛮方法,判断手机发送的客户端标志,兼容性有待提高
  if (isset($_SERVER[‘HTTP_USER_AGENT’])) {

   $clientKeywords = ['nokia','sony','ericsson','mot','samsung','htc','sgh','lg','sharp','sie-','philips','panasonic','alcatel','lenovo','iphone','ipod','blackberry','meizu','android','netfront','symbian','ucweb','windowsce','palm','operamini','operamobi','openwave','nexusone','cldc','midp','wap','mobile'];
  
   //从HTTP_USER_AGENT中查找手机浏览器的关键字
   if (preg_match("/(".implode('|', $clientKeywords).")/i", strtolower($_SERVER['HTTP_USER_AGENT']))) {
       return true;
   }
  

  }

  //协议法,因为有可能不准确,放到最后判断
  if (isset(KaTeX parse error: Expected '}', got 'EOF' at end of input: … if ((strpos(_SERVER[‘HTTP_ACCEPT’], ‘vnd.wap.wml’) !== false) && (strpos(${}_{S}ERVER{[}^{\prime }HTT{P}_{A}CCEP{T}^{\prime }]{,}^{\prime }text/htm{l}^{\prime })===false||(strpos($_SERVER[‘HTTP_ACCEPT’], ‘vnd.wap.wml’) < strpos($_SERVER[‘HTTP_ACCEPT’], ‘text/html’)))) {
  return true;
  }
  }

  return false;
  }