📅 Sync ICS Feeds to Your CalDAV Calendar with Emojis, Deduplication, and Docker
If you’re like me and obsessively track everything — from Austrian public holidays to Formula 1 races and even trash pickup days — you know how painful it can be managing all of that across calendars.
So I built a simple solution: a Python-based tool that syncs ICS feeds directly into a CalDAV calendar (like mailbox.org), complete with:
- ✅ Emoji support
- ✅ Deduplication of events
- ✅ Location-based filtering for Austria
- ✅ Docker support
- ✅ Dry-run mode so nothing breaks 🔥
🎥 Check out the console output in action
💡 Why I Built This
There are lots of calendar tools, but none let me do exactly what I wanted:
- Pull in multiple
.icsfeeds - Filter events based on location (e.g., only Kärnten, Steiermark)
- Add emojis to event names (🗑️ for trash, 🇦🇹 for public holidays)
- Avoid duplicate imports (using UID hashing)
- Easily run as a scheduled task on my Synology NAS
It started as a quick utility for my own use. Now it’s open source and available for anyone to use!
🛠️ Features at a Glance
- 🔁 Sync any
.icsfeed to CalDAV - 📅 All-day events handled properly
- 🇦🇹 Support for Austrian public holiday feed, with filtering by Bundesland
- 🧠 Deterministic UID generation using hashed content
- 🛑 Dry-run support to preview changes
- 🐳 Docker & Docker Compose support
- 💥 Built-in cleanup option for previously imported events
🔧 How It Works
- Loads your
config.jsonwith ICS feeds and emoji mappings - Connects to your CalDAV calendar (e.g., mailbox.org)
- Checks for duplicate events using a unique hash-based UID
- Applies emoji mappings to the event title
- Filters events based on date range and, if set,
import_locations - Imports events, replacing duplicates if needed
You can even preview everything with:
docker-compose run --rm calendar-sync --import --dry-run✍️ Example Config
{
"caldav_url": "https://dav-sso.mailbox.org/caldav/...",
"username": "you@mailbox.org",
"password": "your-app-password",
"timezone": "Europe/Vienna",
"uid_prefix": "ICS-",
"future_event_limit_days": 365,
"ics_feeds": [
{
"url": "https://example.com/feiertage.ics",
"import_locations": "K,St",
"emoji_mapping": {
"§": "🇦🇹",
"default": "🗓️"
}
}
]
}
If you set "import_locations": "K,St", the log output will show you which events are skipped due to unmatched regions like this:
INFO: ⏭️ Skipping 'St. Florian' (2025-05-04) due to unmatched location: OÖ🧪 Use on Synology or Server
I run this on my Synology via a scheduled task:
cd /volume2/docker/appdata/calendar-sync
docker-compose run --rm calendar-sync --cleanup
docker-compose run --rm calendar-sync --importRuns every day at 01:00 🕐 — and my calendar is always up to date.
📦 Where to Get It
You’ll find the source, Dockerfile, instructions and everything here:
👉 GitHub – magicdude4eva/calendar-sync
🤝 Support & Contributions
This project is MIT-licensed and open to PRs, ideas, or feedback.
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