Access hidden Google calendars from CalendarApp? - google-apps-script

Question

I have a web app that creates a hidden calendar
var cal = CalendarApp.createCalendar("Timetable");
cal.setSelected(true);
cal.setHidden(true);
But the same web app starts with code to look for an existing calendar and delete it first
var cals = CalendarApp.getCalendarsByName("Timetable");
for (var i = cals.length; i--; ) {
cals[i].deleteCalendar();
}
However, CalendarApp.getCalendarsByName does not find the "Timetable" calendar.
I have also tried
var cals = CalendarApp.getAllCalendars();
for (var i = cals.length; i--; ) {
if (cals[i].getName()=='Timetable') {
cals[i].deleteCalendar();
}
}
and
var cals = CalendarApp.getAllOwnedCalendars();
for (var i = cals.length; i--; ) {
if (cals[i].getName()=='Timetable') {
cals[i].deleteCalendar();
}
}
none of which are able to find the calendar called "Timetable."
However, the new calendar is created properly and listed in the UI under calendar settings, and if I check the box to make it visible again then all versions of this code find the "Timetable" calendar and delete it, before creating a new one.
Does anyone have any ideas on how I can get a handle to my hidden calendar based only on its name?
My web app executes as the person accessing the script, and is creating this secondary calendar in the user's own Google calendar.

Answer 1

I don't think this is possible using Apps Script built-in Calendar API (the CalendarApp).
You'll have to use the actual Calendar API directly. Luckily it is available as an "Advanced Service" (in your script see the menu Resources > Advanced Google Services, follow the instructions and enable the Calendar API).
Here's a snippet to get a hidden calendar by name:
function getCalIdFromName(name) {
var cals = Calendar.CalendarList.list({showHidden:true,
minAccessRole:'owner', fields:'items(id,summary)'}).items;
for( var i = 0; i < cals.length; i++ )
if( cals[i].summary == name )
return cals[i].id;
return null;
}
function deleteTimetable() {
Calendar.Calendars.remove(getCalIdFromName('Timetable'));
}
Trying to limit the CalendarList results I included the criteria to only return the users own calendars. Since this seems to be your scenario, but you can just omit that to retrieve all.
Another caveat, this simple code that does not handle pagination. Hopefully your users will not own more than 100 calendars (which would require pagination control).
Anyway, it is probably much easier to just store the calendar id right after you created it, using the Properties Service for example. And then retrieve it by id when you need to delete or operate on it (also because the user might change the calendar name).