• Gitea version (or commit ref): any
• Can you reproduce the bug at https://try.gitea.io:
  • Yes

Description

Users should be able to subscribe to their assigned issues (or any other issue search) as an ICS calendar file. This allows integrating gitea issues/TODOs in one's own calendar/task management system (eg. Thunderbird or any calendar/task manager that supports ICS subscriptions)

For example, Gitlab has this feature:

• Enter any search query from the issues dashboard, eg https://gitlab.com/dashboard/issues?assignee_username=nodiscc
• An ICS link appears in the top right corner of search results

• The link points to an ICS file (protected by a unique token) https://gitlab.com/dashboard/issues.ics?assignee_username=nodiscc&due_date=next_month_and_previous_two_weeks&feed_token=XXXXXXXXX&sort=closest_future_date&state=opened. Example contents:

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//GitLab//NONSGML GitLab//EN
CALSCALE:GREGORIAN
X-WR-CALNAME:GitLab Issues
BEGIN:VEVENT
DTSTAMP:20201120T184651Z
UID:AAAA-BBBB-CCCC-DDD-2b12cfece978
DTSTART;VALUE=DATE:20201121
DESCRIPTION:Find out more at https://gitlab.com/nodiscc/awesome-linuxaudio/
 -/issues/7
SUMMARY:Move CI/syntax checks to gitlab CI (in nodiscc/awesome-linuxaudio)
TRANSP:TRANSPARENT
URL:https://gitlab.com/nodiscc/awesome-linuxaudio/-/issues/7
END:VEVENT
END:VCALENDAR

• After subscribing to this ICS file from a calendar management program, issues are displayed according to their due date property on the calendar view: