在 Python 中解析 Nginx 的 http_userid_module cookie

Question

我已经设置nginx userid模块，在向服务器请求匿名跟踪时生成uid cookie。虽然设置cookie的一切都如预期，但我不知道应该如何解析这些cookie（在Python中）以进行进一步分析。

根据nginx的文档(http://nginx.org/en/docs/http/ngx_http_userid_module.html#userid_service)http_userid模块完全符合apache的moduid，并根据apache的Moduid文档(http://www.lexa.ru/programs/mod-uid-eng.html)cookie值实际上包含有价值的数据，例如cookie发布的时间戳。

base64解码部分很容易：）想知道这里是否有人可以帮助完成解析这些cookie中数据所需的其余操作？

Answer 1

import base64
import socket
import struct

def decode_cookie(cookie):
    """decode a u cookie into an uid
    :param cookie: a cookie value that will be decoded into a uid
    :return: string representing the uid
    This algorithm is for version 2 of http://wiki.nginx.org/HttpUseridModule.
    This nginx module follows the apache mod_uid module algorithm, which is
    documented here: http://www.lexa.ru/programs/mod-uid-eng.html.
    """
    # get the raw binary value
    binary_cookie = base64.b64decode(cookie)
    # unpack into 4 parts, each a network byte orderd 32 bit unsigned int
    unsigned_ints = struct.unpack('!4I', binary_cookie)
    # convert from network (big-endian) to host byte (probably little-endian) order
    host_byte_order_ints = [socket.ntohl(i) for i in unsigned_ints]
    # convert to upper case hex value
    uid = 'u=' + ''.join(['{0:08X}'.format(h) for h in host_byte_order_ints])
    return uid

def encode_uid(uid):
    """encode an uid into a u cookie
    :param uid: an uid that will be encoded into a cookie.
    :return: string representing the u cookie
    The algorithm is for version 2 of http://wiki.nginx.org/HttpUseridModule.
    This nginx module follows the apache mod_uid module algorithm, which is
    documented here: http://www.lexa.ru/programs/mod-uid-eng.html.
    """
    # get the hex value of the uid
    hex_value = uid.split('=')[1]
    # convert 128 bit string into 4 32 bit integers
    host_byte_order_ints = [int(hex_value[i:i+8], 16) for i in range(0, 32, 8)]
    # convert from host byte (probably little-endian) to network byte (big-endian) order
    unsigned_ints = [socket.htonl(i) for i in host_byte_order_ints]
    # convert to raw binary value
    binary_cookie = struct.pack('!4I', *unsigned_ints)
    # get the base64 version of the cookie
    cookie = base64.b64encode(binary_cookie)
    return cookie

Answer 2

PHP中@d3w4rd答案的背包，以防有人在找它。

class NginxUniqid
{
    public static function decodeCookie($cookie)
    {
        return strtoupper(join('', array_map(function ($e) {
            return str_pad(
                base_convert($e, 10, 16),
                8, '0', STR_PAD_LEFT
            );
        }, unpack('I4', base64_decode($cookie)))));
    }
    public static function encodeUid($hex)
    {
        return base64_encode(pack(
            'I4',
            base_convert(substr($hex, 0, 8), 16, 10),
            base_convert(substr($hex, 8, 8), 16, 10),
            base_convert(substr($hex, 16, 8), 16, 10),
            base_convert(substr($hex, 24, 8), 16, 10)
        ));
    }
}