This is my first try ever to contribute anything in elisp. The nextcloud calendar app supports the X-PUBLISHED-TTL option if subscribing to an ics file. Nextcloud defaults to a TTL of 1 week, what is much too long for my use case.
When exporting to such a file from org I did not find any way to set this option during export. So I tried to add a defcustom in ox-icalendar.el. The default TTL in this patch is 1 hour. I think this qualifies as an tiny patch, as it is mostly a docstring :-), in case anybody finds this an useful addition. The patch is relative to 9.5.1 from elpa. All comments very much appreciated. And a happy new year to you all Detlef
267a268,280 > (defcustom org-icalendar-ttl "PT1H" > "The time to life for the exported calendar. > Subscribing clients to the exported ics file can derive the time interval > to read the file again from the server. One example of such a client is > the nextcloud calendar, which respects the setting of > X-PUBLISHED-TTL, i.e. X-PUBLISHED-TTL:PT1H . > > See https://icalendar.org/iCalendar-RFC-5545/3-8-2-5-duration.html > for a complete description of possiblee values of this option. I.e. > PT1H stands for 1 hour, PT0H27M34S for 0 hours, 27 minutes and 34 seconds." > :group 'org-export-icalendar > :type 'string) > 303c316,317 < (:icalendar-use-scheduled nil nil org-icalendar-use-scheduled)) --- > (:icalendar-use-scheduled nil nil org-icalendar-use-scheduled) > (:icalendar-ttl nil nil org-icalendar-ttl)) 833c847 < (defun org-icalendar--vcalendar (name owner tz description contents) --- > (defun org-icalendar--vcalendar (name owner tz description ttl contents) 835c849 < NAME, OWNER, TZ, DESCRIPTION and CONTENTS are all strings giving, --- > NAME, OWNER, TZ, DESCRIPTION, TTL and CONTENTS are all strings giving, 837c851,852 < used, a short description and the other components included." --- > used, a short description, the time-to-live resp. refresh period and > the other components included." 843a859 > X-PUBLISHED-TTL:%s 848c864,865 < (org-icalendar-cleanup-string description)) --- > (org-icalendar-cleanup-string description) > (org-icalendar-cleanup-string ttl)) 976a994 > org-icalendar-ttl 1000a1019,1020 > ;; TTL (Refresh period) > org-icalendar-ttl
