Node.js RESTAPI REsponse在执行下一步之前等待

Question

我在做亚马逊莱克斯的工作。在Amazon中，我编写了一个Node.js函数，它调用一个Openweather调用。这是函数。

function todaysweather(intentRequest, callback, data) {
    const location = intentRequest.currentIntent.slots.location;
    const source = intentRequest.invocationSource;
  const outputSessionAttributes = intentRequest.sessionAttributes || {};
  const temp = JSON.parse(outputSessionAttributes.temp || '{}');
  ***console.log("Inside perform request");***
  var endpoint = '/data/2.5/weather?q=${location}&appid=234426bef0d81ef4474073344f';
  var method = 'POST';
  var dataString = JSON.stringify(data);
  var headers = {};
  var responseObject;

  if (method == 'GET') {
    endpoint += '?' + querystring.stringify(data);
  }
  else {
    headers = {
      'Content-Type': 'application/json',
      'Content-Length': dataString.length
    };
  }
  var options = {
    host: host,
    path: endpoint,
    method: method,
    headers: headers
  };
  ***console.log("Before http perform request");***
  var req = https.request(options, function(res) {
    res.setEncoding('utf-8');
    var responseString = '';
    res.on('data', function(data) {
      responseString += data;
    });
  ***console.log("before perform response");***
    res.on('end', function() {
      console.log(responseString);
      responseObject = JSON.parse(responseString);
      var tempVAR = responseObject.main.temp;
      console.log("*************" + tempVAR);
      //success(responseObject);
    });
  });

  req.write(dataString);
  req.end();

  ***console.log("before callback request");***
    callback(close(outputSessionAttributes, 'Fulfilled', { contentType: 'PlainText',
       content: `Okay, I have booked your appointment.  We will see you` }));
}

API调用需要几毫秒的时间才能响应.在那之前，我的下一个代码是执行..。如何阻止它被处决。如果您查看下面的日志“回调请求前”是在“响应请求前”之前执行的，请帮助我了解如何解决这个问题？

启动RequestId: 6 8a17 856-8 ef8-11e7-8a17-afa62db3dcddc版本：$LATEST09:32:13 2017-09-01T09:32:13.734Z 6fafb856-8 ef8-11e7-8a17-afa62db3dcdc event.bot.name=TodaysWeather09:32:13 2017-09-01T09:32:13.735Z 6fafb856-8 ef8-11e7-8a17-afdb623 01T09调度userId=yczl74p0he593v0kduouy5c5nhci50e5，intentName=Todaysweather09:32:13 2017-09-01T09:32:13.735Z 6fafb856-8 ef8-11e7-8a17-afa62db3dcdc09:32:13 2017-09-01T09:32:13.735Z 6fafb856-8 fafb856-8-8a17-afadb3 201709:32:13 2017-09-01T09:32:13.975Z 6fafb856-8ef8-11e7-8a1709-01T09:32:14.190Z 6fafb856-8 ef8-11e7-8a17-afa62db3dcdc09:32:14 2017-09-01T09:32:14.193Z 6fafb856-8 ef8-11e7-8a17-afa62db3dcdc {"coord":{"lon":-71.32，"lat":44.63}，“天气”：{“id”：804，“主”：“云”，“描述”：“阴云”，“图标”：“04n”}，“基础”：“台站”，“主”：{“临时”：280.34，“气压”：1015，“湿度”：70，"temp_min":279.15，"temp_max":281.15}，“能见度”：16093，“风”：{“速度”：2.6，"deg":250}，“云”：{“所有”：90}，"dt":1504257840，"sys":{"type":1，"id":195609:32:14 2017-09-01T09:32:14.233Z 6fafbb856-8 faf8-11e7-8a17-afa62db3dcdc*09:32:14结束：6fb856-8e8-11e7-8a17-afa62db3dcdc

Answer 1

是的，这是因为Node.js的异步特性。您将发送请求，并在此之后调用回调，而无需等待响应。

要等待响应，需要在res.on('end',..__的回调中调用lambda回调。类似于：

res.on('end', function() {
  responseObject = JSON.parse(responseString);
  callback(close(outputSessionAttributes, 'Fulfilled', { contentType: 'PlainText', content: `Okay, I have booked your appointment.  We will see you` }));
});

在这种情况下，只有在从API接收到响应后才会调用lambda回调。

希望这能有所帮助！