PHP 检测机器人，屏蔽内页

PHP 检测机器人，屏蔽内页

<?php
// SpiderHelper::rewrite301();
// SpiderHelper::showRobotTxt();
class SpiderHelper {
	
	/**
	 * 如果是爬虫，301跳转到某个地址
	 * @param string $location
	 */
	public static function rewrite301($location = '/') {
		if(self::isSpider()){
			header('HTTP/1.1 301 Moved Permanently');
			header('Location: '.$location);
			exit();
		}
	}
	
	/**
	 * 显示文件内容
	 * @var unknown
	 */
	public static function showRobotTxt() {
		if(self::isSpider()){
			echo	"User-agent: *\r\n".
					"Disallow: /";
			exit();
		}
	}
	
	/**
	 * 检查是否是爬虫
	 * @param string $userAgent 客户端类型
	 * @return boolean
	 */
	public static function isSpider($userAgent = '') {
		static $kwSpiders = array('bot', 'crawl', 'spider' ,'slurp', 'sohu-search', 'lycos', 'robozilla');
		static $kwBrowsers = array('msie', 'netscape', 'opera', 'konqueror', 'mozilla');
	
		$userAgent = strtolower(empty($userAgent) ? $_SERVER['HTTP_USER_AGENT'] : $userAgent);
		if(strpos($userAgent, 'http://') === false && self::checkStrpos($userAgent, $kwBrowsers)){ // 浏览器
			return false;
		}
		if(self::checkStrpos($userAgent, $kwSpiders)){ // 蜘蛛
			return true;
		}
		return false;
	}
	
	/**
	 * 是否存在数组中的关键字
	 * @param unknown $needle 字符串
	 * @param unknown $haystack 关键字数组
	 * @param string $returnValue 是否返回匹配到的值
	 * @return boolean|Ambigous <boolean, unknown>
	 */
	private static function checkStrpos($needle, $haystack, $returnValue = false) {
		if(empty($needle)){
			return false;
		}
		foreach((array)$haystack as $v) {
			if(strpos($needle, $v) !== false) {
				$return = $returnValue ? $v : true;
				return $return;
			}
		}
		return false;
	}
}