Episode 4.gs

const cc = DataStudioApp.createCommunityConnector();

function getAuthType() {
  return cc.newAuthTypeResponse()
    .setAuthType(cc.AuthType.KEY)
    .setHelpUrl('https://p.nomics.com/cryptocurrency-bitcoin-api')
    .build();
}

function resetAuth() {
  var userProperties = PropertiesService.getUserProperties();
  userProperties.deleteProperty('dscc.key');
}

function isAuthValid() {
  var userProperties = PropertiesService.getUserProperties();
  var key = userProperties.getProperty('dscc.key');
  var res = UrlFetchApp.fetch(`https://api.nomics.com/v1/markets?key=${key}`, { 'muteHttpExceptions': true });
  return res.getResponseCode() == 200;
}

function setCredentials(request) {
  var key = request.key;
  var res = UrlFetchApp.fetch(`https://api.nomics.com/v1/markets?key=${key}`, { 'muteHttpExceptions': true });
  if (res.getResponseCode() != 200) {
    return cc.newSetCredentialsResponse()
      .setIsValid(false)
      .build();
  } else {
    var userProperties = PropertiesService.getUserProperties();
    userProperties.setProperty('dscc.key', key);
    return cc.newSetCredentialsResponse()
      .setIsValid(true)
      .build();
  }
}

function getConfig() {
  const config = cc.getConfig();

  const option1 = config.newOptionBuilder()
    .setLabel('U.S. Dollars (USD)')
    .setValue("USD");
  const option2 = config.newOptionBuilder()
    .setLabel('Euros (EUR)')
    .setValue("EUR");
  const option3 = config.newOptionBuilder()
    .setLabel('Japanese Yen (JPY)')
    .setValue("JPY");
  const option4 = config.newOptionBuilder()
    .setLabel('Pound Sterling (GBP)')
    .setValue("GBP");

  config.newSelectSingle()
    .setId('currency')
    .setName('Please Select a Currency to Quote the Ticker Prices')
    .addOption(option1)
    .addOption(option2)
    .addOption(option3)
    .addOption(option4);

  config.newInfo()
    .setText('To learn more about currencies please go here: https://en.wikipedia.org/wiki/Currency');

  config.setDateRangeRequired(true);

  return config.build();
}

function getFields() {
  const fields = cc.getFields();

  fields.newDimension()
    .setId('date')
    .setName('Date')
    .setDescription('The Date at Midnight')
    .setType(cc.FieldType.YEAR_MONTH_DAY);

  fields.newDimension()
    .setId('ticker')
    .setName('Ticker Symbol')
    .setDescription('The Ticker Symbol')
    .setType(cc.FieldType.TEXT);

  fields.newMetric()
    .setId('prices')
    .setName('Prices')
    .setDescription('The Price of the Cryptocurrency')
    .setType(cc.FieldType.NUMBER);

  return fields;
}

function getSchema() {
  return cc.newGetSchemaResponse()
    .setFields(getFields())
    .build();
}

function getData(request) {
  const key = PropertiesService.getUserProperties().getProperty('dscc.key');
  const ids = request.dimensionsFilters != null ? request.dimensionsFilters[0][0].values.join() : 'BTC,ETH,DOGE';
  const start = request.dateRange.startDate;
  const end = request.dateRange.endDate;
  const currency = request.configParams != null ? request.configParams['currency'] : 'USD';

  let res = UrlFetchApp.fetch(`https://api.nomics.com/v1/currencies/sparkline?key=${key}&ids=${ids}&start=${start}T00%3A00%3A00Z&end=${end}T00%3A00%3A00Z&convert=${currency}`);

  res = JSON.parse(res);

  let requestedIds = request.fields.map(object => object['name']);
  let data = [];

  for (let coin of res) {
    for (let timestamp in coin['timestamps']) {
      let row = [];
      for (let requestedId of requestedIds) {
        switch (requestedId) {
          case 'ticker':
            row.push(coin['currency']);
            break;
          case 'date':
            row.push(coin['timestamps'][timestamp].split('T')[0].replace(/-/g, ''));
            break;
          case 'prices':
            row.push(coin['prices'][timestamp]);
            break;
          default:
            break;
        }
      }
      data.push(row)
    }
  }

  let fields = getFields().forIds(requestedIds);
  
  return cc.newGetDataResponse()
    .setFields(fields)
    .addAllRows(data)
    .build();
}