php获取从百度搜索进入网站的关键词

<?php
 
function search_word_from() {
   $referer = isset($_SERVER['HTTP_REFERER'])?$_SERVER['HTTP_REFERER']:'';
   if(strstr( $referer, 'baidu.com')){ //百度
      preg_match( "|baidu.+wo?r?d=([^\&]*)|is", $referer, $tmp );
       $keyword = urldecode( $tmp[1] );
       $from = 'baidu';
   }elseif(strstr( $referer, 'google.com') or strstr( $referer, 'google.cn')){ //谷歌
      preg_match( "|google.+q=([^\&]*)|is", $referer, $tmp );
       $keyword = urldecode( $tmp[1] );
       $from = 'google';
   }elseif(strstr( $referer, 'so.com')){ //360搜索
      preg_match( "|so.+q=([^\&]*)|is", $referer, $tmp );
       $keyword = urldecode( $tmp[1] );
       $from = '360'; 
   }elseif(strstr( $referer, 'sogou.com')){ //搜狗
      preg_match( "|sogou.com.+query=([^\&]*)|is", $referer, $tmp );
       $keyword = urldecode( $tmp[1] );
       $from = 'sogou';   
   }elseif(strstr( $referer, 'soso.com')){ //搜搜
      preg_match( "|soso.com.+w=([^\&]*)|is", $referer, $tmp );
       $keyword = urldecode( $tmp[1] );
       $from = 'soso';
   }else {
       $keyword ='';
       $from = '';
   }
 
   return array('keyword'=>$keyword,'from'=>$from);
}
 
//以下为测试
//在搜索引擎搜索个关键词，进入网站
$word = search_word_from();
if(!empty($word['keyword'])){
   echo '关键字：'.$word['keyword'].' 来自：'.$word['from'];
}
?>