PHP经过访客来路获取搜索关键词的方法

<?phpclass 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;	}}?>