获取当前URL

function get_url() {
    $sys_protocal = isset($_SERVER['SERVER_PORT']) && $_SERVER['SERVER_PORT'] == '443' ? 'https://' : 'http://';
    $php_self = $_SERVER['PHP_SELF'] ? $_SERVER['PHP_SELF'] : $_SERVER['SCRIPT_NAME'];
    $path_info = isset($_SERVER['PATH_INFO']) ? $_SERVER['PATH_INFO'] : '';
    $relate_url = isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : $php_self.(isset($_SERVER['QUERY_STRING']) ? '?'.$_SERVER['QUERY_STRING'] : $path_info);
    return $sys_protocal.(isset($_SERVER['HTTP_HOST']) ? $_SERVER['HTTP_HOST'] : '').$relate_url;
}