Create Event from Booking Email using Google App Scripts

create_event_from_email.gs

// What to add to the parsed ISO date to get it in correct timezone
TZ_POSTFIX = 'T00:00:00+02:00';
// Email subjects to look at
SUBJECT_NEW_BOOKING = 'New Booking - Some Service';
// Matches '2023-07-14 00:00 - 2023-07-14 00:00' like strings with groups for each date
DATE_RANGE_PATTERN = new RegExp('(\\d{4}-\\d{2}-\\d{2}) 00:00 - (\\d{4}-\\d{2}-\\d{2}) 00:00');
// Regex patterns to extract other content such as name, apartment, email
NAME_PATTERN = new RegExp('<td>Name:<\\/td>[\\n\\s]+<td>(.*)<\\/td>');
APARTMENT_PATTERN = new RegExp('<td>Apartment:<\\/td>[\\n\\s]+<td>(.*)<\\/td>');
EMAIL_PATTERN = new RegExp('<td>Email:<\\/td>[\\n\\s]+<td>(.*)<\\/td>');

function createEventFromNewBookings() {
  matches = findUnreadBookings(SUBJECT_NEW_BOOKING)
  for (var i = 0; i < matches.length; i++) {
    var body = matches[i];
    // Extract date from email body
    var [from_date, to_date] = extractDate(body);
    // Extract other useful content from email body
    var [name, apartment, email] = extractContent(body);
    // Create Calendar event
    createCalendarEvent(name, apartment, email, from_date, to_date);
  }
}

function findUnreadBookings(subject) {
  // Extract HTML body from email for unread matches
  var threads = GmailApp.search('subject:"' + subject + '"');
  var matches = [];
  for (var i = 0; i < threads.length; i++) {
    var thread = threads[i];
    if (thread.isUnread()) {
      var emailMessage = thread.getMessages()[0].getBody();
      matches.push(emailMessage);
      thread.markRead();
    }
  }
  return matches;
}

function extractDate(body) {
  // Extract dates from HTML Body string
  var match = DATE_RANGE_PATTERN.exec(body)
  var from_date = new Date(match[1] + TZ_POSTFIX);
  var to_date = new Date(match[2] + TZ_POSTFIX);
  Logger.log('From date: ' + from_date);
  Logger.log('To date: ' + to_date);
  // It turns out that Smart Brf sends one email per date
  // so the from and to dates will always be the same.
  // We only return one of them.
  return [from_date, to_date];
}

function extractContent(body) {
  // Extract name, apartment, email from HTML Body string
  var name = NAME_PATTERN.exec(body)[1];
  var apartment = APARTMENT_PATTERN.exec(body)[1];
  var email = EMAIL_PATTERN.exec(body)[1];
  Logger.log('Name: ' + name);
  Logger.log('Apartment: ' + apartment);
  Logger.log('Email: ' + email);
  return [name, apartment, email];
}

function createCalendarEvent(name, apartment, email, from_date, to_date) {
  // Create calendar event from the given information
  var title = apartment + ' ' + name;
  var desc = 'Namn: ' + name + '\n' + 'Lägenhet: ' + apartment + '\n' + 'Email: ' + email + '\n'
  if to_date <= from_date {
    // Create for a single day
    var event = CalendarApp.getDefaultCalendar().createAllDayEvent(
      title,
      from_date,
      {description: desc}
     );
  } else {
    // Create for multiple days
  var event = CalendarApp.getDefaultCalendar().createAllDayEvent(
    title,
    from_date,
    to_date,
    {description: desc}
  );
  Logger.log('Event ID: ' + event.getId());
}