回调中的AWS返回回调

您可以使用async模块使其更具可读性和灵活性，并且还可以避免异步问题。像这样写你的东西

/** module used for outbound http requests */
var request = require('request');
var async = require('async');
/** module used for parsing XML easily. https://www.npmjs.com/package/xml2js*/
var parseString = require('xml2js').parseString;
exports.handler = (event, context, callback) => {
    async.waterfall([
        function(next) {
            // testing array of coordinates
            var arrayOfPoints = [39.7683800, -86.1580400, 41.881832, -87.623177];
            var results = getXMLFromNOAA(arrayOfPoints, next);
        },
        function(baseURL, next) {
            request(baseURL, function(error, response, body) {
                if (!error && response.statusCode == 200) {
                    parseString(body, function(err, result) {
                        console.log('inside parseString: ' + result); // <- this prints but it won't show up in the main
                        if (!err)
                            next(null, result);
                    });
                }
            })
        }
    ], function(err, result) {
        if (!err) {
            callback(null, results); // <- returns 'undefined' in the AWS console. I'm assuming race condition.
        }
    })
};
/**
 * getXMLFromNOAA
 *
 * This is a function used for figuring out the functionality of NOAA XML parsing
 *
 * @param arrayOfPoints {Array[Double]} - An evenly numbered index array of latitudes and longitudes
 *
 * @return result {XML/JSON} - weather information abled to be parsed
 */
function getXMLFromNOAA(arrayOfPoints, next) {
    var baseURL = "http://graphical.weather.gov/xml/sample_products/browser_interface/ndfdXMLclient.php?whichClient=NDFDgenLatLonList&lat=&lon=&listLatLon=";
    // for-loop getting all points and dynamically adding them to the query url string
    // iterate 2 at a time since they are coupled coordinates (e.g. [lat1, lng1, lat2, lng2, ... latN, lngN])
    for (var i = 0; i < arrayOfPoints.length; i = i + 2) {
        // if we're at the end of the arrayOfPoints, finish up the chain of query coordinates
        if ((i + 2) == arrayOfPoints.length) {
            baseURL = baseURL.concat(arrayOfPoints[i]);
            baseURL = baseURL.concat("%2C");
            baseURL = baseURL.concat(arrayOfPoints[i + 1]);
        } else {
            baseURL = baseURL.concat(arrayOfPoints[i]);
            baseURL = baseURL.concat("%2C");
            baseURL = baseURL.concat(arrayOfPoints[i + 1]);
            baseURL = baseURL.concat("+");
        }
    }
    // TIME
    baseURL = baseURL.concat("&lat1=&lon1=&lat2=&lon2=&resolutionSub=&listLat1=&listLon1=&listLat2=&listLon2=&resolutionList=&endPoint1Lat=&endPoint1Lon=&endPoint2Lat=&endPoint2Lon=&listEndPoint1Lat=&listEndPoint1Lon=&listEndPoint2Lat=&listEndPoint2Lon=&zipCodeList=&listZipCodeList=&centerPointLat=&centerPointLon=&distanceLat=&distanceLon=&resolutionSquare=&listCenterPointLat=&listCenterPointLon=&listDistanceLat=&listDistanceLon=&listResolutionSquare=&citiesLevel=&listCitiesLevel=&sector=&gmlListLatLon=&featureType=&requestedTime=&startTime=&endTime=&compType=&propertyName=&product=time-series&begin=2016-09-04T00:00:00&end=2016-09-11T00:00:00");
    // CHARACTERISTICS REQUESTED
    // http://graphical.weather.gov/xml/docs/elementInputNames.php
    baseURL = baseURL.concat("&Unit=e&maxt=maxt&mint=mint&temp=temp&appt=appt&rh=rh&sky=sky&wwa=wwa&iceaccum=iceaccum&ptornado=ptornado&phail=phail&ptstmwinds=ptstmwinds&pxtornado=pxtornado&pxhail=pxhail&ptotsvrtstm=ptotsvrtstm&wgust=wgust");
    // Used for testing and seeing the final result
    console.log(baseURL);
    //retun to callback after getting URL
    next(null, baseURL)
}

这不是回调的工作方式。将处理程序更改为如下内容:

exports.handler = (event, context, callback) => {
  var arrayOfPoints = [39.7683800, -86.1580400, 41.881832, -87.623177];
  getXMLFromNOAA(arrayOfPoints, function(result) {
    console.log('returned');
    console.log(result);
    callback(null, result);
  });
};

也取消注释(返回)到getXMLFromNOAA中的callback(result);

NOAA也有一个模块。在重新发明轮子之前，一定要先搜索node-modules/npmjs.com/npms.io。这里的示例https://github.com/thataustin/noaa-forecasts与您正在做的非常相似，所以我将从它开始。

如果你想在未来简化异步的东西，你可以使用babel与async和await关键字。但是你需要确保你首先真正学会了回调和承诺。