liftie/lib/webcams.js

Clean, simple, easy to read, fast ski resort lift status

import Debug from 'debug';
import { LIFTIE_USER_AGENT } from './env.js';
import limiter from './tools/limiter.js';
import { minute } from './tools/millis.js';

const debug = Debug('liftie:webcams');

fetchWebcams.interval = {
  active: 8.5 * minute, // v3 API images are only valid for 10 minutes
  inactive: Number.POSITIVE_INFINITY
};

const limit = limiter(12, 'minute'); // 12 times a minute
const notice = `Webcams provided by
<a href="https://www.windy.com/" target="_blank" rel="noopener">windy.com</a> &mdash;
<a href="https://www.windy.com/webcams/add" target="_blank" rel="noopener">add a webcam</a>
`;

function convert({ title, images, urls }) {
  const name = title.replace(/'/g, '&apos;');
  return {
    name,
    source: urls.detail,
    image: images.current.preview,
    notice
  };
}

function getStatic({ webcams }) {
  if (webcams?.length) {
    return webcams;
  }
}

export default function fetchWebcams(resort, fn) {
  debug('Fetching webcams for %s', resort.id);
  const { WEBCAMS_API_KEY } = process.env;
  if (!resort.ll || !WEBCAMS_API_KEY) {
    debug('API key not defined', resort.ll, process.env);
    return process.nextTick(fn, null, getStatic(resort));
  }
  limit(err => {
    if (err) {
      debug('webcams API limit %s', resort.id);
      return fn(err);
    }
    debug('fetch webcams from Windy for %s', resort.id);

    const {
      ll: [lon, lat]
    } = resort;
    const url = new URL('https://api.windy.com/webcams/api/v3/webcams');
    const { searchParams: sp } = url;
    sp.set('limit', 5);
    sp.set('nearby', `${lat},${lon},5`);
    sp.set('include', 'images,urls');
    fetch(url, {
      headers: {
        Accept: 'application/json',
        'User-Agent': LIFTIE_USER_AGENT,
        'x-windy-api-key': WEBCAMS_API_KEY
      }
    })
      .then(res => res.json())
      .then(onData)
      .catch(onError);

    function onError(err) {
      debug('Webcam API error', err);
      fn(null, getStatic(resort));
    }

    function onData({ webcams }) {
      if (webcams.length < 1) {
        return fn(null, getStatic(resort));
      }
      debug('Webcam API response', webcams);
      fn(null, webcams.map(convert));
    }
  });
}