PHP通过访客来路获取搜索关键词的方法

<?php

class keyword{

public function getKeyword($referer){
if(strpos($referer,"http://www.baidu.com")> -1 ){
$keyword = $this->getbaidukeyword($referer);
}else if(strpos($referer,"http://www.google.com")> -1 ){
$keyword = $this->getgooglekeyword($referer);
}else if(strpos($referer,"http://www.soso.com")> -1 ){
$keyword = $this->getsosokeyword($referer);
}else if(strpos($referer,"http://www.sogou.com")> -1 ){
$keyword = $this->getsogoukeyword($referer);
}

return $keyword;
}

//由来路取得百度关键词
private function getbaidukeyword($str){
$s = strpos($str,'wd=');
if($s>-1){
$str = substr($str,$s+3);
$e = strpos($str,'&');
if($e>-1){
$str = substr($str,0,$e);
}
$str = rawurldecode($str);
}
return $str;
}
//获得谷歌关键词
private function getgooglekeyword($str){
$s = strpos($str,'&q=');
if($s>-1){
$str = substr($str,$s+3);
$e = strpos($str,'&');
if($e>-1){
$str = substr($str,0,$e);
}
$str = rawurldecode($str);
}
return $str;
}
//获得SOSO关键词
private function getsosokeyword($str){
$s = strpos($str,'?w=');
if($s>-1){
$str = substr($str,$s+3);
$e = strpos($str,'&');
if($e>-1){
$str = substr($str,0,$e);
}
$str = rawurldecode($str);
}else{
$s = strpos($str,'&w=');
if($s>-1){
$str = substr($str,$s+3);
$e = strpos($str,'&');
if($e>-1){
$str = substr($str,0,$e);
}
$str = rawurldecode($str);
}
}
return $str;
}
//获得sogou关键词
private function getsogoukeyword($str){
$s = strpos($str,'query=');
if($s>-1){
$str = substr($str,$s+6);
$e = strpos($str,'&');
if($e>-1){
$str = substr($str,0,$e);
}
$str = rawurldecode($str);
}
return $str;
}

}

?>