PHP获取搜索引擎关键字来源（百度、谷歌、雅虎、搜狗、搜搜、必应、有道）

<?php
//获取来自搜索引擎入站时的关键词
function get_keyword($url,$kw_start)
 {
  $start=stripos($url,$kw_start);
  $url=substr($url,$start+strlen($kw_start));
  $start=stripos($url,'&');
   if ($start>0)
   {
    $start=stripos($url,'&');
    $s_s_keyword=substr($url,0,$start);
   }
   else
   {
   $s_s_keyword=substr($url,0);
   }
  return $s_s_keyword;
 }

 $url=isset($_SERVER['HTTP_REFERER'])?$_SERVER['HTTP_REFERER']:'';//获取入站url。
 $search_1="google.com"; //q= utf8
 $search_2="baidu.com"; //wd= gbk
 $search_3="yahoo.cn"; //q= utf8
 $search_4="sogou.com"; //query= gbk
 $search_5="soso.com"; //w= gbk
 $search_6="bing.com"; //q= utf8
 $search_7="youdao.com"; //q= utf8

 $google=preg_match("/\b{$search_1}\b/",$url);//记录匹配情况，用于入站判断。
 $baidu=preg_match("/\b{$search_2}\b/",$url);
 $yahoo=preg_match("/\b{$search_3}\b/",$url);
 $sogou=preg_match("/\b{$search_4}\b/",$url);
 $soso=preg_match("/\b{$search_5}\b/",$url);
 $bing=preg_match("/\b{$search_6}\b/",$url);
 $youdao=preg_match("/\b{$search_7}\b/",$url);
 $s_s_keyword="";
 $bul=$_SERVER['HTTP_REFERER'];
 //获取没参数域名
 preg_match('@^(?:http://)?([^/]+)@i',$bul,$matches);
 $burl=$matches[1];
 //匹配域名设置
 $curl="www.netxu.com";
 if($burl!=$curl){
   if ($google)
  {//来自google
   $s_s_keyword=get_keyword($url,'q=');//关键词前的字符为"q="。
   $s_s_keyword=urldecode($s_s_keyword);
   $urlname="谷歌：";
   $_SESSION["urlname"]=$urlname;
   $_SESSION["s_s_keyword"]=$s_s_keyword;
   //$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎为gbk
  }
  else if($baidu)
  {//来自百度
   $s_s_keyword=get_keyword($url,'wd=');//关键词前的字符为"wd="。
   $s_s_keyword=urldecode($s_s_keyword);
   $s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎为gbk
   $urlname="百度：";
   $_SESSION["urlname"]=$urlname;
   $_SESSION["s_s_keyword"]=$s_s_keyword;
  }
  else if($yahoo)
  {//来自雅虎
   $s_s_keyword=get_keyword($url,'q=');//关键词前的字符为"q="。
   $s_s_keyword=urldecode($s_s_keyword);
   //$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎为gbk
   $urlname="雅虎：";
   $_SESSION["urlname"]=$urlname;
   $_SESSION["s_s_keyword"]=$s_s_keyword;
  }
  else if($sogou)
  {//来自搜狗
   $s_s_keyword=get_keyword($url,'query=');//关键词前的字符为"query="。
   $s_s_keyword=urldecode($s_s_keyword);
   $s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎为gbk
   $urlname="搜狗：";
   $_SESSION["urlname"]=$urlname;
   $_SESSION["s_s_keyword"]=$s_s_keyword;
  }
  else if($soso)
  {//来自搜搜
   $s_s_keyword=get_keyword($url,'w=');//关键词前的字符为"w="。
   $s_s_keyword=urldecode($s_s_keyword);
   $s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎为gbk
   $urlname="搜搜：";
   $_SESSION["urlname"]=$urlname;
   $_SESSION["s_s_keyword"]=$s_s_keyword;
  }
  else if($bing)
  {//来自必应
   $s_s_keyword=get_keyword($url,'q=');//关键词前的字符为"q="。
   $s_s_keyword=urldecode($s_s_keyword);
   //$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎为gbk
   $urlname="必应：";
   $_SESSION["urlname"]=$urlname;
   $_SESSION["s_s_keyword"]=$s_s_keyword;
  }
  else if($youdao)
  {//来自有道
   $s_s_keyword=get_keyword($url,'q=');//关键词前的字符为"q="。
   $s_s_keyword=urldecode($s_s_keyword);
   //$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎为gbk
   $urlname="有道：";
   $_SESSION["urlname"]=$urlname;
   $_SESSION["s_s_keyword"]=$s_s_keyword;
  }
  else{
   $urlname=$burl;
   $s_s_keyword="";
   $_SESSION["urlname"]=$urlname;
   $_SESSION["s_s_keyword"]=$s_s_keyword;
  }
  $s_urlname=$urlname;
  $s_urlkey=$s_s_keyword;
 }
 else{
  $s_urlname=$_SESSION["urlname"];
  $s_urlkey=$_SESSION["s_s_keyword"];
 }
?>