搜索引擎来源关键字分析程序

<?php
/**
 * 分析搜索引擎到来的关键字
 * 
 * 
 * @author zhangjun
 * @charset utf-8
 */
class searchTerms {
	public static $banUrl = array('qq.com','localhost'); //不解析的referer 有利于加快程序处理速度
	
	public static $parseHost = array('baidu','google','360','soso');  //能解析的referer

	
	/**
	 * 主方法
	 * @return boolean || array
	 */
	public static function keyword(){
		if(!isset($_SERVER['HTTP_REFERER']))
			return false;
		$referer = trim($_SERVER['HTTP_REFERER']);
		$refererArr = parse_url($referer);
		
		//判断refer是否来至不需要分析的地址。
		if(self::inBanUrl($refererArr['host'])) 
			return false;
		
		$hasParseFun = false;
		foreach(self::$parseHost as $host) {
			if(strpos ($refererArr['host'],$host) !== false) { 
				$hasParseFun = true;
				break;
			}	
		}
		
		if(!$hasParseFun)
			return false;
		
		$queryVars = array();
		parse_str($refererArr['query'], $queryVars);
		//调用每个搜索引擎的单独处理方法
		$method = 'parse'.ucfirst($host);
		return self::$method($queryVars);
	}
	/* 已取消使用正则的方式。
	public static function buldPattern($rule) {
		$host = str_replace('.', '\.', $rule['host']);
		$patterns = array();
		foreach ($rule['key'] as $key) {
			$patterns[] = $host . '.+?'.$key.'=';
		} 
		return "/(?:" . implode('|', $patterns).')([^&]*)/';
	}*/
	public static function inBanUrl($referer) {
		foreach(self::$banUrl as $url) {
			if(strpos($url, $referer) !== false) 
				return true;
		}
		return false;
	}
	
	public static function parseBaidu($params)
	{
		$searchTerms = '';
		if(isset($params['kw'])) {
			$searchTerms = $params['kw'];
		} else if(isset ($params['wd'])) {
			$searchTerms = $params['wd'];
		} else if(isset ($params['word'])) {
			$searchTerms = $params['word'];
		}

		return isset($params['ie']) && (strtolower($params['ie']) == 'utf-8') ? $searchTerms : iconv('gbk', 'utf-8', $searchTerms);
	}
	
	public static function parseGoogle($params)
	{
		$searchTerms = '';
		if(isset($params['q'])) {
			$searchTerms = $params['q'];
		}
		return isset($params['ie']) && ($params['ie'] == "GB") ? iconv('gbk', 'utf-8', $searchTerms) : $params['q'];
	}
	
	public static function parse360($params)
	{
		$searchTerms = '';
		if(isset($params['q'])) {
			$searchTerms = $params['q'];
		}
		return $searchTerms;
	}
	
	public static function parseSoso($params)
	{
		$searchTerms = '';
		if(isset($params['w'])) {
			$searchTerms = $params['w'];
		}
		return iconv('gbk', 'utf-8', $searchTerms);
	}
}