php 版获取重定向后的地址

2. [代码][PHP]代码     跳至 [1] [2] [全屏预览]

<?php
//取重定向的地址
class RedirectUrl{
	//地址
	var $url;
	//初始化地址
	function RedirectUrl($url){
		$this->url = $url;
	}
	/**
	 * get_redirect_url()
	 * 取重定向的地址
	 *
	 * @param string $url
	 * @return string
	 */
	private function get_redirect_url($url){
		$redirect_url = null;

		$url_parts = @parse_url($url);
		if (!$url_parts) return false;
		if (!isset($url_parts['host'])) return false; //can't process relative URLs
		if (!isset($url_parts['path'])) $url_parts['path'] = '/';

		$sock = fsockopen($url_parts['host'], (isset($url_parts['port']) ? (int)$url_parts['port'] : 80), $errno, $errstr, 30);
		if (!$sock) return false;

		$request = "HEAD " . $url_parts['path'] . (isset($url_parts['query']) ? '?'.$url_parts['query'] : '') . " HTTP/1.1\r\n";
		$request .= 'Host: ' . $url_parts['host'] . "\r\n";
		$request .= "Connection: Close\r\n\r\n";
		fwrite($sock, $request);
		$response = '';
		while(!feof($sock)) $response .= fread($sock, 8192);
		fclose($sock);

		if (preg_match('/^Location: (.+?)$/m', $response, $matches)){
			return trim($matches[1]);
		} else {
			return false;
		}
	}

	/**
	 * get_all_redirects()
	 * 取所有重定向地址
	 *
	 * @param string $url
	 * @return array
	 */
	private function get_all_redirects($url){
		$redirects = array();
		while ($newurl = $this->get_redirect_url($url)){
			if (in_array($newurl, $redirects)){
				break;
			}
			$redirects[] = $newurl;
			$url = $newurl;
		}
		return $redirects;
	}

	/**
	 * get_final_url()
	 * 取实际地址
	 * 
	 * @param string $url
	 * @return string
	 */
	function get_final_url(){
		$redirects = $this->get_all_redirects($this->url);

		if (count($redirects)>0){
			return array_pop($redirects);
		} else {
			return $this->url;
		}
	}
}

/**
 * get_show_pic
 * 取最终要显示的图片地址
 *
 * @param string $url
 * @return  string
 */
function get_show_pic($url,$noimg = 'noimg.gif',$newimg="http://special.ku6img.com/projects/2010/d-color/images/slt-1.jpg"){
	$obj = new RedirectUrl($url);

	$realurl = $obj->get_final_url();

	if(strpos($realurl,$noimg)>0){
		return $newimg;
	}
	return $url;
}
//参考
echo "<img src='".get_show_pic("http://i2.ku6img.com/encode/picpath/2010/12/9/14/1294948410019/5.jpg")."'/>";
?>