php获取从百度、谷歌等搜索引擎进入网站关键词

<?php
function search_word_from() {
 $referer = isset($_SERVER['HTTP_REFERER'])?$_SERVER['HTTP_REFERER']:'';
 if(strstr( $referer, 'baidu.')){ //百度
  preg_match( "|baidu.+wo?r?d=([^\\&]*)|is", $referer, $tmp );
  $keyword = urldecode( $tmp[1] );
  $from = 'baidu';
 }elseif(strstr( $referer, 'google.') or strstr( $referer, 'google.')){ //谷歌
  preg_match( "|google.+q=([^\\&]*)|is", $referer, $tmp );
  $keyword = urldecode( $tmp[1] );
  $from = 'google';
 }elseif(strstr( $referer, 'so.')){ //360搜索
  preg_match( "|so.+q=([^\\&]*)|is", $referer, $tmp );
  $keyword = urldecode( $tmp[1] );
  $from = '360'; 
 }elseif(strstr( $referer, 'sogou.')){ //搜狗
  preg_match( "|sogou..+query=([^\\&]*)|is", $referer, $tmp );
  $keyword = urldecode( $tmp[1] );
  $from = 'sogou'; 
 }elseif(strstr( $referer, 'soso.')){ //搜搜
  preg_match( "|soso..+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'];
}
?>