反爬（四）

网站四处罚信息反爬破解

在Chrome中请求列表页时，刷新网页观察网络请求发现，先是跳转到一个中转链接：http://www.pbc.gov.cn/WZWSREL3poZW5nd3Vnb25na2FpLzEyNzkyNC8xMjgwNDEvMjE2MTQyMS9pbmRleC5odG1s?wzwschallenge=V1pXU19DT05GSVJNX1BSRUZJWF9MQUJFTDUxODU2NjI=，然后再跳转回到列表页。

下面我们来具体看看中间的过程：

1. 请求列表页http://www.pbc.gov.cn/zhengwugongkai/127924/128041/2161421/index.html

   请求头中没有携带Cookie，请求响应返回的Cookie为：wzws_cid=6fe01577596a409d77f565c225c8c5a664a89799db7d0985a62413f32f6ba6e2d15be123681d18238c4216ea84a3b705e2a6611466562bf4c66a22358bff5b241873a84dab388b5da80fc2ecf6a2acf41f764692145f8bb5a57762e2fe08c49c; path=/; expires=Thu, 19 Sep 2019 08:41:13 GMT

   此时请求返回的是一个携带大量加密js的HTML文件；

2. 自动去请求http://www.pbc.gov.cn/WZWSREL3poZW5nd3Vnb25na2FpLzEyNzkyNC8xMjgwNDEvMjE2MTQyMS9pbmRleC5odG1s?wzwschallenge=V1pXU19DT05GSVJNX1BSRUZJWF9MQUJFTDUxODU2NjI=

   请求头中携带的Cookie为：

   wzws_cid=6fe01577596a409d77f565c225c8c5a664a89799db7d0985a62413f32f6ba6e2d15be123681d18238c4216ea84a3b705e2a6611466562bf4c66a22358bff5b241873a84dab388b5da80fc2ecf6a2acf41f764692145f8bb5a57762e2fe08c49c

   请求响应返回的Cookie为：

   wzws_cid=6fe01577596a409d77f565c225c8c5a664a89799db7d0985a62413f32f6ba6e2d15be123681d18238c4216ea84a3b705b81cba9208ba6c30f9c7a9ed07941d8e; path=/; expires=Thu, 19 Sep 2019 08:41:13 GMT

   此时请求返回的是一个302的重定向页面；

3. 自动再次请求列表页http://www.pbc.gov.cn/zhengwugongkai/127924/128041/2161421/index.html

   请求头中携带的Cookie为：

   wzws_cid=6fe01577596a409d77f565c225c8c5a664a89799db7d0985a62413f32f6ba6e2d15be123681d18238c4216ea84a3b705b81cba9208ba6c30f9c7a9ed07941d8e

   请求响应中没有返回Cookie；

   但是返回了我们想要获取的列表页内容；

通过观察总结，我们发现步骤2是为了返回给我们请求需要的真正的Cookie，只有携带步骤2返回的Cookie才可以成功请求到数据，所以我们每次只要进行一次步骤2的操作去获取cookie就可以了；但是，步骤2的请求链接是如何获取的呢？

我做了三次请求，分别将步骤2的url(省略了前缀)都复制了下来：

/WZWSREL3poZW5nd3Vnb25na2FpLzEyNzkyNC8xMjgwNDEvMjE2MTQyMS9pbmRleC5odG1s?wzwschallenge=V1pXU19DT05GSVJNX1BSRUZJWF9MQUJFTDg2MzAxMQ==

/WZWSREL3poZW5nd3Vnb25na2FpLzEyNzkyNC8xMjgwNDEvMjE2MTQyMS9pbmRleC5odG1s?wzwschallenge=V1pXU19DT05GSVJNX1BSRUZJWF9MQUJFTDIwMjU3MjM=

/WZWSREL3poZW5nd3Vnb25na2FpLzEyNzkyNC8xMjgwNDEvMjE2MTQyMS9pbmRleC5odG1s?wzwschallenge=V1pXU19DT05GSVJNX1BSRUZJWF9MQUJFTDYxNjI1MzU=

仔细观察，发现变化的是wzwschalleng参数的值，更准确地说，wzwschalleng参数的前半部分V1pXU19DT05GSVJNX1BSRUZJWF9MQUJFTD都是不变的，改变的只有末尾的八九个字符。

这里发现wzwschalleng参数的值很像base64编码,我们全部拿来解码：

import base64
base64.b64decode('V1pXU19DT05GSVJNX1BSRUZJWF9MQUJFTDg2MzAxMQ==')
b'WZWS_CONFIRM_PREFIX_LABEL863011'

base64.b64decode('V1pXU19DT05GSVJNX1BSRUZJWF9MQUJFTDIwMjU3MjM=')
b'WZWS_CONFIRM_PREFIX_LABEL2025723'

base64.b64decode('V1pXU19DT05GSVJNX1BSRUZJWF9MQUJFTDYxNjI1MzU=')
b'WZWS_CONFIRM_PREFIX_LABEL6162535'

通过解码对比发现，改变的只有末尾的七位数字；到这里我们就该去思考如何获取每次变化的wzwschalleng或者更精确的后面的这七位数字。

这时我们想到了，第一次请求之后返回的js代码，几乎可以推测就是这段js代码，生成了wzwschalleng的值。

我们在chrome的source栏下面给网页打上script事件断点，这样当网页执行到该js代码时会停下来，便于我们观察,具体操作如图：

注：当我们刷新无法在该js代码处停下时，是因为缓存的原因，清空缓存后，使用Ctrl+F5强制刷新

之后我们看到了全部的js代码如下：

eval(function(p, a, c, k, e, r) {
    e = function(c) {
        return c.toString(a)
    }
    ;
    if (!''.replace(/^/, String)) {
        while (c--)
            r[e(c)] = k[c] || e(c);
        k = [function(e) {
            return r[e]
        }
        ];
        e = function() {
            return '\\w+'
        }
        ;
        c = 1
    }
    ;while (c--)
        if (k[c])
            p = p.replace(new RegExp('\\b' + e(c) + '\\b','g'), k[c]);
    return p
}('0 1="2";0 3="4";0 5="6";0 7="8";0 9="a";', 11, 11, 'var|dynamicurl|/WZWSREL3poZW5nd3Vnb25na2FpLzEyNzkyNC8xMjgwNDEvMjE2MTQyMS9pbmRleC5odG1s|wzwsquestion|;YSl^]a|wzwsfactor|2963|wzwsmethod|WZWS_METHOD|wzwsparams|WZWS_PARAMS'.split('|'), 0, {}));

var encode_version = 'sojson.v5'
  , jezoh = '__0x3fb5e'
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(function(_0x5bc68b, _0x259158) {
    var _0x102152 = function(_0x1797a6) {
        while (--_0x1797a6) {
            _0x5bc68b['push'](_0x5bc68b['shift']());
        }
    };
    _0x102152(++_0x259158);
}(__0x3fb5e, 0x123));
var _0x56ae = function(_0xca96c7, _0x241ea9) {
    _0xca96c7 = _0xca96c7 - 0x0;
    var _0x57cca1 = __0x3fb5e[_0xca96c7];
    if (_0x56ae['initialized'] === undefined) {
        (function() {
            var _0x228394 = typeof window !== 'undefined' ? window : typeof process === 'object' && typeof require === 'function' && typeof global === 'object' ? global : this;
            var _0x356c10 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
            _0x228394['atob'] || (_0x228394['atob'] = function(_0x16460d) {
                var _0x4e207e = String(_0x16460d)['replace'](/=+$/, '');
                for (var _0x15f638 = 0x0, _0x2abf93, _0x3df9f8, _0x479e2a = 0x0, _0x411a0f = ''; _0x3df9f8 = _0x4e207e['charAt'](_0x479e2a++); ~_0x3df9f8 && (_0x2abf93 = _0x15f638 % 0x4 ? _0x2abf93 * 0x40 + _0x3df9f8 : _0x3df9f8,
                _0x15f638++ % 0x4) ? _0x411a0f += String['fromCharCode'](0xff & _0x2abf93 >> (-0x2 * _0x15f638 & 0x6)) : 0x0) {
                    _0x3df9f8 = _0x356c10['indexOf'](_0x3df9f8);
                }
                return _0x411a0f;
            }
            );
        }());
        var _0x172d34 = function(_0xa28d48, _0x346449) {
            var _0x55c23f = [], _0x3809ab = 0x0, _0x5298ee, _0x3c825f = '', _0x8b8e9a = '';
            _0xa28d48 = atob(_0xa28d48);
            for (var _0xee1bef = 0x0, _0x3023b5 = _0xa28d48['length']; _0xee1bef < _0x3023b5; _0xee1bef++) {
                _0x8b8e9a += '%' + ('00' + _0xa28d48['charCodeAt'](_0xee1bef)['toString'](0x10))['slice'](-0x2);
            }
            _0xa28d48 = decodeURIComponent(_0x8b8e9a);
            for (var _0x308939 = 0x0; _0x308939 < 0x100; _0x308939++) {
                _0x55c23f[_0x308939] = _0x308939;
            }
            for (_0x308939 = 0x0; _0x308939 < 0x100; _0x308939++) {
                _0x3809ab = (_0x3809ab + _0x55c23f[_0x308939] + _0x346449['charCodeAt'](_0x308939 % _0x346449['length'])) % 0x100;
                _0x5298ee = _0x55c23f[_0x308939];
                _0x55c23f[_0x308939] = _0x55c23f[_0x3809ab];
                _0x55c23f[_0x3809ab] = _0x5298ee;
            }
            _0x308939 = 0x0;
            _0x3809ab = 0x0;
            for (var _0x66c563 = 0x0; _0x66c563 < _0xa28d48['length']; _0x66c563++) {
                _0x308939 = (_0x308939 + 0x1) % 0x100;
                _0x3809ab = (_0x3809ab + _0x55c23f[_0x308939]) % 0x100;
                _0x5298ee = _0x55c23f[_0x308939];
                _0x55c23f[_0x308939] = _0x55c23f[_0x3809ab];
                _0x55c23f[_0x3809ab] = _0x5298ee;
                _0x3c825f += String['fromCharCode'](_0xa28d48['charCodeAt'](_0x66c563) ^ _0x55c23f[(_0x55c23f[_0x308939] + _0x55c23f[_0x3809ab]) % 0x100]);
            }
            return _0x3c825f;
        };
        _0x56ae['rc4'] = _0x172d34;
        _0x56ae['data'] = {};
        _0x56ae['initialized'] = !![];
    }
    var _0x190c72 = _0x56ae['data'][_0xca96c7];
    if (_0x190c72 === undefined) {
        if (_0x56ae['once'] === undefined) {
            _0x56ae['once'] = !![];
        }
        _0x57cca1 = _0x56ae['rc4'](_0x57cca1, _0x241ea9);
        _0x56ae['data'][_0xca96c7] = _0x57cca1;
    } else {
        _0x57cca1 = _0x190c72;
    }
    return _0x57cca1;
};
function _0x412a72(_0x2a28c0) {
    var _0x4257c9 = {
        'bwGZX': _0x56ae('0x0', 'jo5I'),
        'mGirf': function _0x2eb028(_0x5ab0bc, _0x5505f4) {
            return _0x5ab0bc < _0x5505f4;
        },
        'hOkXt': function _0x16449b(_0x22286c, _0x41c8cd) {
            return _0x22286c & _0x41c8cd;
        },
        'RJeYY': function _0x24beb6(_0x59303b, _0x576d3b) {
            return _0x59303b == _0x576d3b;
        },
        'cFxMb': function _0x45b03c(_0xadce3d, _0x5416a9) {
            return _0xadce3d >> _0x5416a9;
        },
        'spzgJ': function _0x3c313d(_0x19fd11, _0xcacabb) {
            return _0x19fd11 << _0xcacabb;
        },
        'VdlKD': function _0x2427d5(_0x23b25b, _0x23b39e) {
            return _0x23b25b & _0x23b39e;
        },
        'VDeWo': function _0x1ef1b0(_0x476993, _0x40dd2a) {
            return _0x476993 == _0x40dd2a;
        },
        'gHLRp': function _0x16afb3(_0x4bdebb, _0x1065a7) {
            return _0x4bdebb >> _0x1065a7;
        },
        'biRta': function _0x301047(_0x2ada60, _0x1c4232) {
            return _0x2ada60 | _0x1c4232;
        },
        'oKMpY': function _0x1d0b02(_0x547e37, _0x500868) {
            return _0x547e37 << _0x500868;
        },
        'HlUXJ': function _0x21902c(_0x16ae1a, _0x466bbf) {
            return _0x16ae1a >> _0x466bbf;
        },
        'vuJTm': function _0x2fea95(_0x34f7b5, _0x59e46f) {
            return _0x34f7b5 << _0x59e46f;
        },
        'lHuwG': function _0x1339d0(_0x3c775a, _0x3450ae) {
            return _0x3c775a >> _0x3450ae;
        },
        'fpeDs': function _0x52b661(_0x318fc3, _0x59aa7b) {
            return _0x318fc3 & _0x59aa7b;
        },
        'HqwlU': function _0x2144ca(_0x4799d4, _0x25b745) {
            return _0x4799d4 | _0x25b745;
        },
        'nPBKx': function _0x42b833(_0xe339b1, _0x5c500c) {
            return _0xe339b1 & _0x5c500c;
        },
        'ZRhVT': function _0xc9529d(_0x5ed560, _0x4383da) {
            return _0x5ed560 & _0x4383da;
        },
        'bdZKt': _0x56ae('0x1', '5jBa')
    };
    var _0x6c47cd = _0x4257c9[_0x56ae('0x2', 'LFWf')][_0x56ae('0x3', 'Q@8l')]('|')
      , _0x3a5836 = 0x0;
    while (!![]) {
        switch (_0x6c47cd[_0x3a5836++]) {
        case '0':
            _0x27d1f5 = '';
            continue;
        case '1':
            var _0x27d1f5, _0x4262d0, _0xc876d4;
            continue;
        case '2':
            _0x4262d0 = 0x0;
            continue;
        case '3':
            while (_0x4257c9[_0x56ae('0x4', '*h#g')](_0x4262d0, _0xc876d4)) {
                _0x5526a7 = _0x4257c9[_0x56ae('0x5', 'a6w(')](_0x2a28c0['charCodeAt'](_0x4262d0++), 0xff);
                if (_0x4257c9['RJeYY'](_0x4262d0, _0xc876d4)) {
                    _0x27d1f5 += _0x2097d8[_0x56ae('0x6', ')Z%%')](_0x4257c9[_0x56ae('0x7', 'iAGA')](_0x5526a7, 0x2));
                    _0x27d1f5 += _0x2097d8['charAt'](_0x4257c9[_0x56ae('0x8', 'IM$w')](_0x4257c9[_0x56ae('0x9', 'Dk(l')](_0x5526a7, 0x3), 0x4));
                    _0x27d1f5 += '==';
                    break;
                }
                _0x138cf5 = _0x2a28c0['charCodeAt'](_0x4262d0++);
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                    _0x27d1f5 += _0x2097d8[_0x56ae('0xc', 'j%QO')](_0x4257c9[_0x56ae('0xd', ')Z%%')](_0x4257c9[_0x56ae('0xe', 'L6ge')](_0x4257c9[_0x56ae('0xf', '02EH')](_0x5526a7, 0x3), 0x4), _0x4257c9[_0x56ae('0x10', '5jBa')](_0x4257c9[_0x56ae('0x11', 'j%QO')](_0x138cf5, 0xf0), 0x4)));
                    _0x27d1f5 += _0x2097d8[_0x56ae('0x12', '02EH')](_0x4257c9[_0x56ae('0x13', 'L6ge')](_0x4257c9['VdlKD'](_0x138cf5, 0xf), 0x2));
                    _0x27d1f5 += '=';
                    break;
                }
                _0x4093e6 = _0x2a28c0[_0x56ae('0x14', '%FZJ')](_0x4262d0++);
                _0x27d1f5 += _0x2097d8[_0x56ae('0x15', 'd2rH')](_0x4257c9['lHuwG'](_0x5526a7, 0x2));
                _0x27d1f5 += _0x2097d8['charAt'](_0x4257c9[_0x56ae('0x16', 'Zp5!')](_0x4257c9['VdlKD'](_0x5526a7, 0x3) << 0x4, _0x4257c9[_0x56ae('0x17', '%FZJ')](_0x138cf5, 0xf0) >> 0x4));
                _0x27d1f5 += _0x2097d8[_0x56ae('0x12', '02EH')](_0x4257c9[_0x56ae('0x18', '*FHt')](_0x4257c9[_0x56ae('0x19', '*FHt')](_0x4257c9['nPBKx'](_0x138cf5, 0xf), 0x2), _0x4257c9[_0x56ae('0x1a', 'scqQ')](_0x4093e6, 0xc0) >> 0x6));
                _0x27d1f5 += _0x2097d8[_0x56ae('0x1b', 'eygr')](_0x4257c9['ZRhVT'](_0x4093e6, 0x3f));
            }
            continue;
        case '4':
            return _0x27d1f5;
        case '5':
            _0xc876d4 = _0x2a28c0['length'];
            continue;
        case '6':
            var _0x5526a7, _0x138cf5, _0x4093e6;
            continue;
        case '7':
            var _0x2097d8 = _0x4257c9[_0x56ae('0x1c', 'LFWf')];
            continue;
        }
        break;
    }
}
function _0x344cd4() {
    var _0x53d9fc = {
        'GjCbS': function _0x1a0314(_0x33da81, _0xe25eb5) {
            return _0x33da81 < _0xe25eb5;
        },
        'JBFUL': function _0x1af799(_0x51aa2f, _0x2e4887) {
            return _0x51aa2f + _0x2e4887;
        }
    };
    var _0x3c9135 = 0x0;
    var _0x43beea = 0x0;
    for (_0x43beea = 0x0; _0x53d9fc[_0x56ae('0x1d', 'uGC9')](_0x43beea, wzwsquestion[_0x56ae('0x1e', 'V2r4')]); _0x43beea++) {
        _0x3c9135 += wzwsquestion[_0x56ae('0x1f', '!2cw')](_0x43beea);
    }
    _0x3c9135 *= wzwsfactor;
    _0x3c9135 += 0x1b207;
    return _0x53d9fc[_0x56ae('0x20', 'd2rH')](_0x56ae('0x21', 'Rau%'), _0x3c9135);
}
function _0x2ff265(_0x26b826, _0xea8bd1) {
    var _0x253f74 = {
        'ogjLK': _0x56ae('0x22', 'Qy14'),
        'izgsL': 'post',
        'eMCME': function _0x3b581c(_0xd2391, _0x1a9ef1) {
            return _0xd2391 != _0x1a9ef1;
        },
        'aCWaI': function _0x5c65fc(_0x1402c7, _0x41e446) {
            return _0x1402c7 < _0x41e446;
        },
        'OTFrl': _0x56ae('0x23', 'Rau%')
    };
    var _0x370b5e = _0x253f74[_0x56ae('0x24', '!2cw')][_0x56ae('0x25', 'i[Ts')]('|')
      , _0x1ba457 = 0x0;
    while (!![]) {
        switch (_0x370b5e[_0x1ba457++]) {
        case '0':
            _0x15a9ed['method'] = _0x253f74[_0x56ae('0x26', 'uGC9')];
            continue;
        case '1':
            return _0x15a9ed;
        case '2':
            var _0x15a9ed = document[_0x56ae('0x27', 'Q@8l')](_0x56ae('0x28', ')Z%%'));
            continue;
        case '3':
            if (_0x253f74[_0x56ae('0x29', 'YXCs')](_0xea8bd1['search']('='), -0x1)) {
                var _0x573df6 = _0xea8bd1[_0x56ae('0x2a', 'LFWf')]('&');
                for (var _0x426cb4 = 0x0; _0x253f74[_0x56ae('0x2b', '57vf')](_0x426cb4, _0x573df6[_0x56ae('0x2c', '*FHt')]); _0x426cb4++) {
                    var _0x3ddbc7 = _0x56ae('0x2d', 'V]Be')['split']('|')
                      , _0x1fdb10 = 0x0;
                    while (!![]) {
                        switch (_0x3ddbc7[_0x1fdb10++]) {
                        case '0':
                            _0x2a293f[_0x56ae('0x2e', 'iAGA')] = _0x422f0a[0x0];
                            continue;
                        case '1':
                            var _0x2a293f = document['createElement'](_0x253f74[_0x56ae('0x2f', 'a6w(')]);
                            continue;
                        case '2':
                            var _0x422f0a = _0x8ad1c0['split']('=');
                            continue;
                        case '3':
                            var _0x8ad1c0 = _0x573df6[_0x426cb4];
                            continue;
                        case '4':
                            _0x15a9ed[_0x56ae('0x30', 'WuNj')](_0x2a293f);
                            continue;
                        case '5':
                            _0x2a293f['value'] = _0x422f0a[0x1];
                            continue;
                        }
                        break;
                    }
                }
            }
            continue;
        case '4':
            _0x15a9ed[_0x56ae('0x31', '!2cw')]();
            continue;
        case '5':
            _0x15a9ed[_0x56ae('0x32', '02EH')] = _0x26b826;
            continue;
        case '6':
            _0x15a9ed['style']['display'] = _0x56ae('0x33', '%FZJ');
            continue;
        case '7':
            document[_0x56ae('0x34', 'HLR(')]['appendChild'](_0x15a9ed);
            continue;
        }
        break;
    }
}
function _0x33f22a() {
    var _0x532424 = {
        'hwQpj': function _0x3b4af9(_0x2ff2ab) {
            return _0x2ff2ab();
        },
        'lYfvS': function _0x242f23(_0x57f673, _0x33b4b3) {
            return _0x57f673(_0x33b4b3);
        },
        'VvOsr': function _0x33a26c(_0xb8a476, _0x580dd6) {
            return _0xb8a476 + _0x580dd6;
        },
        'vOmWg': _0x56ae('0x35', 'YXCs'),
        'LaaBO': function _0x1b637c(_0x5c57e1, _0x41b90a) {
            return _0x5c57e1 == _0x41b90a;
        },
        'eneJI': 'post'
    };
    var _0xb14971 = _0x532424[_0x56ae('0x36', 'jo5I')](_0x344cd4);
    var _0x10ace8 = _0x532424[_0x56ae('0x37', 'a6w(')](_0x412a72, _0xb14971[_0x56ae('0x38', '*8t[')]());
    var _0x35ace3 = _0x532424[_0x56ae('0x39', ')9A&')](dynamicurl, _0x532424[_0x56ae('0x3a', 'N&Yh')]) + _0x10ace8;
    if (_0x532424['LaaBO'](wzwsmethod, _0x532424[_0x56ae('0x3b', 'Q@8l')])) {
        _0x2ff265(_0x35ace3, wzwsparams);
    } else {
        window[_0x56ae('0x3c', ')9A&')] = _0x35ace3;
    }
}
_0x33f22a();
;if (!(typeof encode_version !== _0x56ae('0x3d', 'QE(m') && encode_version === _0x56ae('0x3e', 'LFWf'))) {
    window[_0x56ae('0x3f', 'Q@8l')](_0x56ae('0x40', 'YtnB'));
}
;encode_version = 'sojson.v5';

经过漫长的三秒钟的冷静，开始研究这段一丢丢也看不懂的js代码。

首先要找函数入口，从上到下看过来发现，先是执行了eval(function(p, a, c, k, e, r)...，再就是从函数_0x33f22a()开始执行。

我们在_0x33f22a()函数内部打断点，查看变量值的情况，如下图所示：

我们发现变量_0xb14971的值为WZWS_CONFIRM_PREFIX_LABEL4914759，这个值看起来好像很熟悉，没错正是我们前面base64解码后的值，将该值进行base64编码就是wzwschalleng的值。

那么我们看_0xb14971的值是怎么算出来的，发现他后面调用了_0x344cd4方法，我们进入该方法，打上断点查看变量值的的情况：

我们发现_0x3c9135变量的值是一个七位的数字，后面return _0x53d9fc[_0x56ae('0x20', 'd2rH')](_0x56ae('0x21', 'Rau%'), _0x3c9135)，我们用鼠标把这一串选中，发现其值为WZWS_CONFIRM_PREFIX_LABEL8455744，因为我们上面得到的结论是，只要更改最后面这七位数字的值就可以得到每次变化的wzwschalleng的值。所以我们只需要把这个最核心的函数抠出来就可以：

function _0x344cd4() {
    var _0x53d9fc = {
        'GjCbS': function _0x1a0314(_0x33da81, _0xe25eb5) {
            return _0x33da81 < _0xe25eb5;
        },
        'JBFUL': function _0x1af799(_0x51aa2f, _0x2e4887) {
            return _0x51aa2f + _0x2e4887;
        }
    };
    var _0x3c9135 = 0x0;
    var _0x43beea = 0x0;
    for (_0x43beea = 0x0; _0x53d9fc[_0x56ae('0x1d', 'uGC9')](_0x43beea, wzwsquestion[_0x56ae('0x1e', 'V2r4')]); _0x43beea++) {
        _0x3c9135 += wzwsquestion[_0x56ae('0x1f', '!2cw')](_0x43beea);
    }
    _0x3c9135 *= wzwsfactor;
    _0x3c9135 += 0x1b207;
    return _0x53d9fc[_0x56ae('0x20', 'd2rH')](_0x56ae('0x21', 'Rau%'), _0x3c9135);
}

我们的目标是能够独立运行该函数，所以需要去修改这段代码，在for循环之前都是定义变量，无需修改，for循环的终止条件中_0x56ae('0x1d', 'uGC9')其实是"GjCbS",_0x56ae('0x1e', 'V2r4')是length。

小技巧：我们将这两个字符串，复制到chrome的console中，按回车看输出就知道了；在console中执行copy(_0x56ae('0x1e', 'V2r4'))还可以直接复制出其值。

这里还有两个重要的变量，wzwsquestion和wzwsfactor，去哪找呢？这时候想起来，一开始不是执行了一段eval()代码嘛，我们执行一下看看：

太巧了！这段代码，执行完之后，正好初始化了wzwsquestion和wzwsfactor这两个变量。

其实，我们仔细观察eval执行时的默认参数值，可以发现这两个值隐藏其中，该函数做的工作只是将原始字符串做了分割之类的工作。

'var|dynamicurl|/WZWSREL2Z6aHNoYW5naGFpLzExMzU3Ny8xMTQ4MzIvMTE0OTE4L2luZGV4Lmh0bWw=|wzwsquestion|GT#rs1mW}J{x,GghI6|wzwsfactor|1574|wzwsmethod|WZWS_METHOD|wzwsparams|WZWS_PARAMS'

这就是那段原始的字符串，所以我们只要写正则匹配一下提出这两个值就可以了,所以最终我们只要改写_0x344cd4方法就行了。

此外，还有一点要注意，原来的js代码中为有这样一个语句_0x3c9135 += 0x1b207;，其实我们保持原样也是可以的运行的，但是有必要指出，0x1b207表示十六进制的111111，不要和这段代码的变量形式_0x...弄混。

下面是完整的爬取代码，包括改写后的_0x344cd4方法：

# _*_ coding:utf-8 _*_
# @Time :2019/9/18 10:53
import requests
import execjs
import base64
import re


class BankOfChina(object):
    Request_Headers = {"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 "
                                     "(KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36",
                       "Host": "www.pbc.gov.cn",
                       "Referer": "http://www.pbc.gov.cn/zhengwugongkai/127924/128041/2161421/index.html",
                       "Upgrade-Insecure-Requests": '1',
                       }

    def __init__(self):
        self._url = 'http://www.pbc.gov.cn/zhengwugongkai/127924/128041/2161421/index.html'
        self._url1 = 'http://www.pbc.gov.cn/WZWSREL3poZW5nd3Vnb25na2FpLzEyNzkyNC8xMjgwNDEvMjE2MTQyMS9pbmRleC5odG1s?wzwschallenge={}'
        # 为了简化cookie变化方面的操作，这里使用session
        self._session = requests.session()
        self._factor = None
        self._question = None

    def request_data_page(self):
        for _ in range(3):
            try:
                response = self._session.get(self._url, headers=self.Request_Headers)
            except Exception as e:
                print(e)
            else:
                if response.status_code == 200:
                    self._factor = int(re.findall(r'wzwsfactor\|(\d+)\|', response.text)[0])
                    self._question = re.findall(r'wzwsquestion\|(.*?)\|', response.text)[0]
                    break

    @staticmethod
    def get_js():
        js_str = """
        function _0x344cd4(factor, wzwsquestion) {
            var _0x53d9fc = {
                'GjCbS': function _0x1a0314(_0x33da81, _0xe25eb5) {
                    return _0x33da81 < _0xe25eb5;
                },
                'JBFUL': function _0x1af799(_0x51aa2f, _0x2e4887) {
                    return _0x51aa2f + _0x2e4887;
                }
            };
            var _0x3c9135 = 0x0;
            var _0x43beea = 0x0;
            for (_0x43beea = 0x0; _0x53d9fc['GjCbS'](_0x43beea, wzwsquestion['length']); _0x43beea++) {
                _0x3c9135 += wzwsquestion['charCodeAt'](_0x43beea);
            }
            _0x3c9135 *= factor;
            return _0x3c9135+111111
        }
        """
        return js_str

    def decrypt_fucntion(self):
        js_str = self.get_js()
        ctx = execjs.compile(js_str)
        b = ctx.call('_0x344cd4', self._factor, self._question)
        a = base64.b64encode('WZWS_CONFIRM_PREFIX_LABEL{}'.format(b).encode()).decode()
        self._url1 = self._url1.format(a)

    def request_page(self):
        for _ in range(3):
            try:
                response = self._session.get(self._url1, headers=self.Request_Headers, allow_redirects=True)
            except Exception as e:
                print(e)
            else:
                if response.status_code == 200:
                    response.encoding = 'utf-8'
                    print(response.text)
                    break


if __name__ == "__main__":
    bank = BankOfChina()
    bank.request_data_page()
    bank.decrypt_fucntion()
    bank.request_page()
    # bank.request_data_page()

上面的request_page方法中，也可以设置不允许重定向，那么其返回的状态码应该为302，我们只需要取其返回的cookie，然后拿去再去请求列表页即可。