I am adding a feature to my event calendar application to provide iCalendar (ics) file downloads for the events. I want to generate the VTIMEZONE Component, but all I have is the PHP's Timezone value from date_default_timezone_get(). Here's an example of a VTIMEZONE Component for Eastern Time (US & Canada) that was generated by Outlook:
BEGIN:VTIMEZONE
TZID:Eastern Time (US & Canada)
BEGIN:STANDARD
DTSTART:16011104T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:16010311T020000
RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
END:DAYLIGHT
END:VTIMEZONE
This would behave like PHP's "America/New_York" time zone, but how would I automate the generation of it?