PHP独立Session数据库存储操作类分享(4)

/**
         * Fetches an alternate IP address of the current visitor, attempting to detect proxies etc.
         *
         * @return      string
         */
        static function fetch_alt_ip()
        {
                $alt_ip = $_SERVER[‘REMOTE_ADDR'];

if (isset($_SERVER[‘HTTP_CLIENT_IP']))
                {
                        $alt_ip = $_SERVER[‘HTTP_CLIENT_IP'];
                }
                else if (isset($_SERVER[‘HTTP_FROM']))
                {
                        $alt_ip = $_SERVER[‘HTTP_FROM'];
                }

return $alt_ip;
        }

/**
     * Returns the IP address with the specified number of octets removed
     *
     * @param    string    IP address
     *
     * @return    string    truncated IP address
     */
    static function fetch_substr_ip($ip, $length = null)
    {
        return implode(‘.', array_slice(explode(‘.', $ip), 0, 4 – $length));
    }

/**
     * Fetches a default session. Used when creating a new session.
     *
     * @param    integer    User ID the session should be for
     *
     * @return    array    Array of session variables
     */
    public function fetch_session($userid = 0)
    {
        $sessionhash = self::fetch_sessionhash();

$this->set_cookie(‘sessionhash', $sessionhash);

return array(
            ‘crc32sid'      => sprintf(‘%u', crc32($sessionhash)),
            ‘sessionhash'   => $sessionhash,
            ‘idhash'        => $this->_session_idhash,
            ‘userid'        => $userid,
            ‘ipaddress'     => $this->_session_host,
            ‘lastactivity'  => date(‘Y-m-d H:i:s', TIMENOW),
            ‘location'      => $_SERVER[‘REQUEST_URI'],
            ‘loggedin'      => $userid ? 1 : 0,
            ‘heartbeat'     => date(‘Y-m-d H:i:s', TIMENOW)
        );
    }

public function get_cookie($cookiename)
    {
        $full_cookiename = $this->_config[‘cookie_prefix'] . $cookiename;