Equim-chan / csu-ems-api

'use strict';

const superagent = require('superagent'),

      co         = require('co'),

      thunkify   = require('thunkify');

superagent.Request.prototype.endThunk = thunkify(superagent.Request.prototype.end);

// 直接从主页上扒下来的，加密算法

const encodeInp = (input) => {

    const keyStr = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

    let output = '';

    let chr1, chr2, chr3 = '';

    let enc1, enc2, enc3, enc4 = '';

    let i = 0;

    do {

        chr1 = input.charCodeAt(i++);

        chr2 = input.charCodeAt(i++);

        chr3 = input.charCodeAt(i++);

        enc1 = chr1 >> 2;

        enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);

        enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);

        enc4 = chr3 & 63;

        if (isNaN(chr2)) {

            enc3 = enc4 = 64;

        } else if (isNaN(chr3)) {

            enc4 = 64;

        }

        output += keyStr.charAt(enc1) + keyStr.charAt(enc2) + keyStr.charAt(enc3) + keyStr.charAt(enc4);

    } while (i < input.length);

    return output;

};

exports = module.exports = {

    // 登入模块

    login: co.wrap(function *(id, pwd) {

        let ires, iires;

        // 通过GET首页，来获取cookie

        try {

            ires = yield superagent

                             .get('http://csujwc.its.csu.edu.cn/jsxsd')

                             .endThunk();

        } catch (err) {

            let message = {

                inner: `Failed to get the Cookie for login.\n${err.stack}`,

                public: '获取Cookie失败'

            };

            throw message;

        }

        const headers = {

            Host: 'csujwc.its.csu.edu.cn',

            Connection: 'keep-alive',

            'Cache-Control': 'max-age=0',

            Accept: 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',

            Origin: 'http://csujwc.its.csu.edu.cn',

            'Upgrade-Insecure-Requests': 1,

            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36',

            'Content-Type': 'application/x-www-form-urlencoded',

            Referer: 'http://csujwc.its.csu.edu.cn/jsxsd/',

            'Accept-Encoding': 'gzip, deflate',

            'Accept-Language': 'zh-CN,zh;q=0.8',

            Cookie: ires.headers['set-cookie']

        };

        try {

            iires = yield superagent

                              .post('http://csujwc.its.csu.edu.cn/jsxsd/xk/LoginToXk')

                              .set(headers)

                              .type('form')

                              .send({ encoded: `${encodeInp(id)}%%%${encodeInp(pwd)}` })

                              .endThunk();

        } catch (err) {

            let message = {

                inner: `Failed to login\n${err.stack}`,

                public: '登录失败'

            };

            throw message;

        }

        if (/POST/i.test(iires.req.method)) {

            let err = new Error('The request method to the logged-in page is POST instead of GET');

            let message = {

                inner: `Failed to login (possibily id or password provided were wrong)\n${err.stack}`,

                public: '登录失败，可能是用户名或密码错误，请确认参数已URL转义'

            };

            throw message;

        }

        return headers;

    }),

    // 登出模块

    logout: co.wrap(function *(headers) {

        try {

            yield superagent

                      .get(`http://csujwc.its.csu.edu.cn/jsxsd/xk/LoginToXk?method=exit&tktime=${new Date().getTime()}`)

                      .set(headers)

                      .endThunk();

        } catch (err) {

            // res已经sent了，所以没有public的message

            let message = {

                inner: `Failed to logout\n${err.stack}`

            };

            throw message;

        }

    })

};