webtask-openexchangerate

webtask-openexchangerate.js

const request = require('request');

const OPEN_EXCHANGE_API_URL = 'https://openexchangerates.org/api';
const OE_LATEST = `${OPEN_EXCHANGE_API_URL}/latest.json`;

module.exports = function(ctx, done) {
  const APP_ID = ctx.data.APP_ID;

  const url = `${OE_LATEST}?app_id=${APP_ID}`;

  // Get the data from the storage to prevent unnecessary requests
  ctx.storage.get((err, data) => {
    if (err) {
      return done(err);
    }

    const now = Date.now();
    const dataTime = (data || {}).time || 0;

    // If the data is recent enough (less than 1 hour)
    if (now - dataTime <= 1 * 60 * 60 * 1000) {
      return done(null, data.body);
    }

    // otherwise we fetch the remote api
    request.get(url, (geterr, resp) => {
      if (geterr) {
        return done(geterr);
      }

      const body = JSON.parse(resp.body);
      const dataBody = {
        timestamp: body.timestamp,
        base: body.base,
        rates: body.rates
      };

      ctx.storage.set(
        {
          time: now,
          body: dataBody
        },
        error => {
          if (error) {
            return done(error);
          }
          return done(null, dataBody);
        }
      );
    });
  });
};