Google Calendar API - Clear all events - google-calendar-api

Question

I'm trying to clear all the events of a google calendar using the calendar ID.
https://developers.google.com/resources/api-libraries/documentation/calendar/v3/python/latest/calendar_v3.calendars.html#clear
Attempting it, gives a "400 Bad Request" response from either Python or a simple curl call using the Google API Explorer:
{
"error": {
"errors": [
{
"domain": "global",
"reason": "invalid",
"message": "Invalid Value"
}
],
"code": 400,
"message": "Invalid Value"
}
}
From either the API explorer or the python API I'm providing only the calendar ID of the corresponding (non-primary) calendar I want to delete.
In Python:
service.calendars().clear(calendarId=<calid-found-in-calendarList().list()>).execute()
Which returns:
<HttpError 400 when requesting https://www.googleapis.com/calendar/v3/calendars/<calendar-id>4%40group.calendar.google.com/clear? returned "Invalid Value". Details: "[{'domain': 'global', 'reason': 'invalid', 'message': 'Invalid Value'}]">
Any idea what I'm doing wrong?

Answer 1

When I had tested the clear method of Calendars in Calendar API v3 before, I had experienced the same situation with you. When I used the value of primary, no error occurs. All events of the primary calendar are deleted. But, when I used the calendar ID except for the primary calendar, the same issue occurred.
When I saw the official document, it says Clears a primary calendar. This operation deletes all events associated with the primary calendar of an account.. But about calendarId in this method, it also says Calendar identifier. To retrieve calendar IDs call the calendarList.list method. If you want to access the primary calendar of the currently logged in user, use the "primary" keyword..
These documents consuse me. So, I checked this "clear" method at Discovery API. Ref It says as follows.
"clear": {
"parameters": {
"calendarId": {
"location": "path",
"required": true,
"type": "string",
"description": "Calendar identifier. To retrieve calendar IDs call the calendarList.list method. If you want to access the primary calendar of the currently logged in user, use the \"primary\" keyword."
}
},
"scopes": [
"https://www.googleapis.com/auth/calendar"
],
"httpMethod": "POST",
"id": "calendar.calendars.clear",
"description": "Clears a primary calendar. This operation deletes all events associated with the primary calendar of an account.",
"parameterOrder": [
"calendarId"
],
"path": "calendars/{calendarId}/clear"
},
From above document, I thought that the calendar ID can be retrieved by the calendarList.list method. But, this "clear" method might not be able to be used for the calendar except for the primary calendar.
And, when I saw the error message, when the calendar ID like ####group.calendar.google.com is used, the error of "message": "Invalid Value" occurs. But, when sample is used as the calendar ID, "message": "Not Found" is returned. It seems that the API might search the calendar. In this case, even when the URL encoding is used, the same issue occurs. From this situation, I thought that this might be a bug.
But, I'm not sure whether this is the current specification or a bug. So, I searched this situation at the issue tracker. But, unfortunately, I couldn't find the same issue. So how about reporting this at the Google issue tracker? Ref
Reference:
Calendars: clear

Answer 2

Something to add to this when I encountered the same issue. Seeing that clearing secondary calendars of events is not currently an option, you can outright delete the calendar and re-create it however, the downside to this is the change in the calendar id on re-creation.
Delete calendar documentation
Deletes a secondary calendar. Use calendars.clear for clearing all events on primary calendars.