CalendarChanger

CalendarChanger is a self-hosted iCalendar (ICS) proxy that fixes and enriches exported calendar feeds. The project began when the University of Twente adopted TimeEdit in 2024. While TimeEdit provided technically valid ICS files, it stored all details inside the description field instead of using the correct iCalendar fields such as LOCATION and ATTENDEE. This made the data unreadable in most calendar apps. CalendarChanger acts as a middle layer between TimeEdit and the calendar client, extracting and reformatting event data to fully leverage standard ICS semantics. It cleans titles, assigns teachers as attendees, and separates lectures, exams, and practicals into individual feeds so users can color-code them in their calendar.
It also adds richer context by inserting Apple Maps locations and linking building names to a custom Mazemap redirect endpoint that resolves rooms to Mazemap locations. The system runs continuously, fetching updates from the original feed and serving always up-to-date subscriptions.
The web interface lets users hide or modify events such as cancelled classes or changed times even though the source is read-only. Each event is hashed by its contents so when TimeEdit updates an event it reverts to its original form ensuring consistency. The backend is built with ASP.NET Core and Razor Pages, containerized with Docker, and deployed automatically with Ansible to a private cloud server.