根據(jù)抓包的方式，獲取請求地址來獲取火車票信息：
需要的模塊：npm install https

https://kyfw.12306.cn/otn/leftTicket/query?leftTicketDTO.train_date=2016-09-01&leftTicketDTO.from_station=ADULT&leftTicketDTO.to_station=BJP&purpose_codes=ADULT


var request     = require('request');
var https       = require('https');

//獲取火車票信息
exports.getTrainInfo = function(req, res) {
var url = '/otn/leftTicket/query?leftTicketDTO.train_date='+req.body.date+'&leftTicketDTO.from_station='+req.body.start+'&leftTicketDTO.to_station='+req.body.end+'&purpose_codes=ADULT';

    //生成GET請求的參數(shù)
    var options = {
        hostname: 'kyfw.12306.cn',
        port: 443,
        path: url,
        method: 'GET',
        rejectUnauthorized: false
    };

    var request = https.request(options , function(response){
    response.setEncoding("utf8");
    
        var str = '';
        //拼接數(shù)據(jù)流字符串
        response.on('data',function(chunk){
            str += chunk;
        });
    
        response.on('end',function(chunk){
            res.json(JSON.parse(str));
        });
    
        response.on('error',function(e){
            console.log(e.message);
            res.json({msg:e.message});
        });
    
        request.end();
    });

}