met-ie.js

/* metEireannForecastNode - the main node in this package. */

module.exports = function (RED) {
    'use strict';

    const http = require("http");
    const xml2js = require("xml2js");
    const { DateTime } = require("luxon");

    /**
     * 
     * @param {*} config - configuration for this node.
     */
    function metEireannForecastNode(config) {
        RED.nodes.createNode(this, config);
        this.lat = config.lat;
        this.long = config.long;
        const node = this;

        node.on('input', function (msg, send, done) {
            // compatibility with Node-RED 0.x
            send = send || function(...args) { node.send.apply(node, args) };
            done = done || function(text, msg) { if (text) { node.error(text, msg); } };

            node.status({
                fill: "blue",
                shape: "dot",
                text: "requesting"
            });

            const now = DateTime.now().startOf('hour').toISO({
                suppressMilliseconds: true,
                suppressSeconds: true,
                includeOffset: false
            });
            const url = `http://metwdb-openaccess.ichec.ie/metno-wdb2ts/locationforecast?lat=${node.lat};long=${node.long};from=${now};to=${now}`;

            http.get(url, (res) => {
                const { statusCode } = res;

                if (statusCode !== 200) {
                    let error = new Error(`Request failed: ${statusCode}`);
                    res.resume();
                    handleError(node, error, done);
                    return;
                }
                
                res.setEncoding("utf8");
                let rawData = "";
                res.on("data", (chunk) => { rawData += chunk; });

                res.on("end", () => {
                    let opts = {
                        valueProcessors: [ xml2js.processors.parseNumbers ],
                        attrValueProcessors: [ xml2js.processors.parseNumbers ]
                    }

                    xml2js.parseString(rawData, opts, function (err, result) {
                        if (err) {
                            handleError(node, err, done);
                            return;
                        }

                        let current = result.weatherdata.product[0].time[0].location[0];
                        let rainCurrent = result.weatherdata.product[0].time[1].location[0];

                        msg.payload = {
                            temperature: current.temperature[0].$['value'],
                            windDirection: current.windDirection[0].$['name'],
                            windDirectionDeg: current.windDirection[0].$['deg'],
                            windSpeed: current.windSpeed[0].$['mps'],
                            windSpeedBeaufort: current.windSpeed[0].$['beaufort'],
                            globalRadiation: current.globalRadiation[0].$['value'],
                            humidity: current.humidity[0].$['value'],
                            pressure: current.pressure[0].$['value'],
                            cloudiness: current.cloudiness[0].$['percent'],
                            lowClouds: current.lowClouds[0].$['percent'],
                            mediumClouds: current.mediumClouds[0].$['percent'],
                            highClouds: current.highClouds[0].$['percent'],
                            dewPoint: current.dewpointTemperature[0].$['value'],
                            rain: rainCurrent.precipitation[0].$['value'],
                            rainProbability: rainCurrent.precipitation[0].$['probability']
                        };

                        send(msg);
                        node.status({});
                        done();
                    });

                });

            }).on("error", (err) => {
                handleError(node, err, done);
            });

        }); // end node('on')
    } // end metEireannForecastNode

    function handleError(node, err, done) {
        node.error(err.message);
        node.status({
            fill: "red",
            shape: "ring",
            text: "error"
        });
        done(err);
    }

    RED.nodes.registerType("met-ie", metEireannForecastNode);
}