使用https模块进行远程请求

npm install https
npm install request

进行远程请求前先拼装好请求数据

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请求的参数
    var options = {
        hostname: 'kyfw.12306.cn',
        port: 443,
        path: url,
        method: 'GET',
        rejectUnauthorized: false
    };

进行远程请求

https.request(options, function(response){
  var str = '';
  //接收数据
  response.on('data', function(chunk){
    str += chunk;
  });
  response.on('end', function(){
    //处理数据  
    response.setEncoding('utf8');
    
    console.log(str);
  });
  
});