Cryptowatch Historical Rates for Google Apps Script

cryptowatch-historical-rates.gs

// cryptowatch-historical-rates.gs
// Cryptowatch Historical Rates for Google Apps Script
// Version: 1.0
//
// Usage:
// =fetchCryptowatchRateFor("bitfinex", "BCHUSD", "2018-03-01")
// =fetchCryptowatchRateFor("bitfinex", "BCHUSD", "2018-03-01", "open")
// Defaults to closing price
function fetchCryptowatchRateFor(venue, symbol, date, which) {
  var index = ['open', 'high', 'low', 'close'].indexOf(which || "close");
  if (index === -1) throw ("which shoul be open, high, low, or close");
  
  var date = new Date(date + 'T00:00:00.000Z');
  var ts = Math.floor((date.getTime() / 1000)).toString();

  var url = Utilities.formatString(
    'https://api.cryptowat.ch/markets/%s/%s/ohlc?before=%s&after=%s&periods=86400',
    venue,
    symbol,
    ts,
    ts
  );

  var res = UrlFetchApp.fetch(url);
  var raw = res.getContentText();
  var points = JSON.parse(raw).result['86400'];
  var point = points[0];
  
  // 0=date, 1=open, 2=high, 3=low, 4=close, 5=volume
  return point[index + 1];
}

function testFetchCryptowatchRateFor() {
  Logger.log(fetchCryptowatchRateFor('bitfinex', 'BCHUSD', '2018-03-14'));
}