ooo-calendar.js

// Adapted from https://developers.google.com/apps-script/articles/vacation-calendar

var TEAM_CALENDAR_ID = 'c_xxxxxxxxxxxx@group.calendar.google.com';
var MONTHS_IN_ADVANCE = 2;
var WHOLE_DAY_HOURS_THRESHOLD = 6;
var USER_EMAILS = [
];

// The maximum script run time under Apps Script Pro is 30 minutes; this setting
// will be used to report when the script is about to reach that limit.
var MAX_PRO_RUNTIME_MS = 29 * 60 * 1000;

/**
 * Look through the domain users' public calendars and add any
 * 'vacation' or 'out of office' events to the team calendar.
 */
function syncTeamVacationCalendar() {
  // Define the calendar event date range to search.
  var today = new Date();
  var startDate = new Date();
  startDate.setDate(startDate.getDate() - 7) // Last week
  var endDate = new Date();
  endDate.setMonth(endDate.getMonth() + MONTHS_IN_ADVANCE);

  // For each user, find events having one or more of the keywords in the event
  // summary in the specified date range. Import each of those to the team
  // calendar.
  var count = 0;
  var timeout = false;
  for (var i = 0; i < USER_EMAILS.length; i++) {
    if (isTimeUp(today, new Date())) {
      timeout = true;
      break;
    }
    var user = USER_EMAILS[i];
    var username = user.split('@')[0];

    var lastRun = PropertiesService.getScriptProperties().getProperty('lastRun-' + user);
    lastRun = lastRun ? new Date(lastRun) : null;

    findEvents(user, startDate, endDate, lastRun).forEach(function(event) {
      if (event.start.dateTime) {
        // Convert long events to day-events to reduce clutter in shared calendars
        var start = new Date(event.start.dateTime)
        var end = new Date(event.end.dateTime)
        var durationHours = (end - start) / 1000 / 60 / 60
        if (durationHours >= WHOLE_DAY_HOURS_THRESHOLD) {
          event.start.date = formatDate(start)
          delete event.start.dateTime
          if (end.getHours() >= 12) {
            // End is exclusive, so it must be the date after
            // However, if the coming back time is before 10am, don't count it.
            end.setDate(end.getDate() + 1)
          }
          event.end.date = formatDate(end)
          delete event.end.dateTime
        }
      }

      event.summary = '[' + username + '] ' + event.summary;
      event.organizer = {
        id: TEAM_CALENDAR_ID
      };
      event.attendees = [];
      Logger.log('Importing: %s', event.summary);
      try {
        Calendar.Events.import(event, TEAM_CALENDAR_ID);
        PropertiesService.getScriptProperties().setProperty('lastRun-' + user, today);
        count++;
      } catch (e) {
        Logger.log('Error attempting to import event: %s. Skipping.', e.toString());
      }
    });
  }
  Logger.log('Imported ' + count + ' events');
  if (timeout) {
    Logger.log('Execution time about to hit quota limit; execution stopped.');
  }
  var executionTime = ((new Date()).getTime() - today.getTime()) / 1000.0;
  Logger.log('Total execution time (s) : ' + executionTime); ;
}

/**
 * In a given user's calendar, look for occurrences of the given keyword
 * in events within the specified date range and return any such events
 * found.
 * @param {string} user the user's primary email String.
 * @param {string} keyword the keyword String to look for.
 * @param {Date} start the starting Date of the range to examine.
 * @param {Date} end the ending Date of the range to examine.
 * @param {Date} opt_since a Date indicating the last time this script was run.
 * @return {object[]} an array of calendar event Objects.
 */
function findEvents(user, start, end, opt_since) {
  var params = {
    timeMin: formatDateTime(start),
    timeMax: formatDateTime(end),
    maxAttendees: 1,
    showDeleted: true,
  };
  // Logger.log('Importing user %s %s-%s', user, start, end);
  if (opt_since) {
    // This prevents the script from examining events that have not been
    // modified since the specified date (that is, the last time the
    // script was run).
    params['updatedMin'] = formatDateTime(opt_since);
  }
  try {
    var responses = Calendar.Events.list(user, params)
    return responses.items.filter(function(item) {
      return item.eventType == 'outOfOffice';
    });
  } catch (e) {
    Logger.log('Error retriving events for %s: %s; skipping', user, e.toString());
    return [];
  }
}

function eventMatches(event, keywords) {
  for (var i = 0; i < length(keywords); i++) {
    if (event.summary.toLowerCase().indexOf(keywords[i]) != -1) {
      return true;
    }
  }

  return false;
}

function formatDate(date) {
    var d = new Date(date),
        month = '' + (d.getMonth() + 1),
        day = '' + d.getDate(),
        year = d.getFullYear();

    if (month.length < 2) 
        month = '0' + month;
    if (day.length < 2) 
        day = '0' + day;

    return [year, month, day].join('-');
}

/**
 * Return an RFC3339 formated date String corresponding to the given
 * Date object.
 * @param {Date} date a Date.
 * @return {string} a formatted date string.
 */
function formatDateTime(date) {
  return Utilities.formatDate(date, 'UTC', 'yyyy-MM-dd\'T\'HH:mm:ssZ');
}

/**
 * Compares two Date objects and returns true if the difference
 * between them is more than the maximum specified run time.
 *
 * @param {Date} start the first Date object.
 * @param {Date} now the (later) Date object.
 * @return {boolean} true if the time difference is greater than
 *     MAX_PROP_RUNTIME_MS (in milliseconds).
 */
function isTimeUp(start, now) {
  return now.getTime() - start.getTime() > MAX_PRO_RUNTIME_MS;
}