php的URL重定向header()函数

// URL重定向

function redirect($url, $time=0, $msg=”) {

//多行URL地址支持

$url = str_replace(array(“n”, “r”), ”, $url);

if ( empty($msg) )

$msg = “系统将在{$time}秒之后自动跳转到{$url}!”;

if (!headers_sent()) {

// redirect

if (0 === $time) {

header(‘Location: ‘ . $url);

} else {

header(“refresh:{$time};url={$url}”);

echo($msg);

}

exit();

} else {

$str = “”;

if ($time != 0)

$str .= $msg;

exit($str);

}

}

//url重定向2

function redirect($url) {

echo “

”;

exit();

}

$url = "www.111com.net";

if (!empty($url))

{

Header("HTTP/1.1 303 See Other"); //这条语句可以不写

Header("Location: $url");

}

?>

/**

* get_redirect_url()

* Gets the address that the provided URL redirects to,

* or FALSE if there's no redirect.

*

* @param string $url

* @return string

*/

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/1.1rn";

$request .= 'Host: ' . $url_parts['host'] . "rn";

$request .= "Connection: Closernrn";

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()

* Follows and collects all redirects, in order, for the given URL.

*

* @param string $url

* @return array

*/

function get_all_redirects($url){

$redirects = array();

while ($newurl = get_redirect_url($url)){

if (in_array($newurl, $redirects)){

break;

}

$redirects[] = $newurl;

$url = $newurl;

}

return $redirects;

}

/**

* get_final_url()

* Gets the address that the URL ultimately leads to.

* Returns $url itself if it isn't a redirect.

*

* @param string $url

* @return string

*/

function get_final_url($url){

$redirects = get_all_redirects($url);

if (count($redirects)>0){

return array_pop($redirects);

} else {

return $url;

}

}