fetch-eu-currencies.js

#!/usr/bin/env node

"use strict";

const fs = require("fs");
const convert = require("xml-js");
const request = require("axios");
const { format } = require("date-fns");
const { skewDays, loadYaml } = require("./misc/util");
const UniCache = require("./misc/unicache");

const config = loadYaml('./config.yaml');
const savePath = config.currencyFilePath || "./data/currencies";
const debug = config.DEBUG;
const cacheType = config.cacheType || "file";

const namePrefix = "currencies-";
const url =
  config.currencyUrl ||
  "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml";
console.log(url);
const keepDays = config.keepDays || 7;

const runNodeSchedule = config.runNodeSchedule || true;
// Currency rates are available around 16:00 hours
const scheduleHours = config.scheduleHours;
const scheduleMinutes = config.scheduleEuMinutes;

let schedule;
let runSchedule;
if (runNodeSchedule) {
  schedule = require("node-schedule");
  runSchedule = new schedule.RecurrenceRule();
  runSchedule.hour = scheduleHours;
  runSchedule.minute = scheduleMinutes;
}

const DB_PREFIX = namePrefix;
const DB_OPTIONS = {
  cacheType: cacheType,
  syncOnWrite: true,
  //syncInterval: 600,
  savePath: savePath,
};
const cacheName = `${DB_PREFIX}latest`;
const currencyDb = new UniCache(cacheName, DB_OPTIONS);

const options = {
  headers: {
    accept: "application/xml",
    "Content-Type": "text/xml",
  },
  method: "GET",
};

function getEuroRates(cur) {
  const obj = {};
  for (let i = 0; i < cur.length; i++) {
    obj[cur[i]._attributes.currency] = cur[i]._attributes.rate * 1;
  }
  obj["EUR"] = 1;
  return obj;
}

async function getCurrencies() {
  retireDays(keepDays);

  request(url, options)
    .then(function (body) {
      const result = convert.xml2js(body.data, { compact: true, spaces: 4 });
      const root = result["gesmes:Envelope"].Cube.Cube;
      const obj = {
        status: "OK",
        date: root._attributes.time,
        base: "EUR",
        rates: getEuroRates(root.Cube),
      };

      //currencyDb.createObject(`${DB_PREFIX}latest`, obj);
      currencyDb.init(obj);
      console.log("Currencies stored as", `${DB_PREFIX}latest`);
      currencyDb.createObject(`${DB_PREFIX}${obj.date}`, obj);
      console.log("Currencies stored as", `${DB_PREFIX}${obj.date}`);
      if (debug) {
        console.log(JSON.stringify(obj, null, 2));
      }
    })
    .catch(function (err) {
      if (err.response) {
        console.log("Error:", err.response.status, err.response.statusText);
        console.log("Headers:", err.response.headers);
      }
    });
}
async function retireDays(offset) {
  // Count offset days backwards
  offset *= -1;
  const retireDate = skewDays(offset);
  const keys = await currencyDb.dbKeys(`${DB_PREFIX}${retireDate}'*'`);
  console.log("Retiring", keys);
  keys.forEach(async (key) => {
    if (key <= `${DB_PREFIX}${retireDate}`) {
      await currencyDb.deleteObject(key);
    }
  });
}

if (runNodeSchedule) {
  console.log("Fetch currency rates scheduling started..");
  schedule.scheduleJob(runSchedule, getCurrencies);
}

//currencyDb = new UniCache(null, DB_OPTIONS);

getCurrencies();