CardDAV and CalDAV sync for the Frappe Framework
davsync is a Frappe v16 app that keeps the site's contacts in step with a CardDAV address book and imports a CalDAV calendar. It works with Nextcloud, Radicale, Baïkal, SOGo and other standard servers.
- Contacts, two-way. vCards become Frappe
Contactrecords with e-mails, phone numbers, addresses, birthday, notes and photo. Changes on either side are synced; when both sides change the same card, the server's notes and photo are kept and the site's fields win. - Calendar. Events with external attendees are imported into Frappe's
Event. Recurring series are expanded 90 days ahead. Invitations you declined are left out (or cancelled once you decline them). Writing events (and the invitations your server sends for them) is opt-in per account. - Ignore rules. Attendee patterns such as
*@newsletter.example.comand whole series that should never be imported. - Safety nets. ETag preconditions on every write, a sync token per account, and a guard that refuses to archive or cancel more than 20 records and 30 % of an account after a suspicious full listing. On the push side, more than 20 deletions within an hour switch push off until you switch it on again.
- Hardened against hostile input. The sync bookkeeping fields cannot be set through the API or
the desk. Requests only go to the account's server over https, never follow redirects, and only
touch objects inside the configured address book or calendar. Deletes always carry
If-Match. Recurrence rules are expanded only inside the sync window; rules that never match or need too many steps are skipped, logged and reported in the calendar result. XML is parsed with defusedxml and responses are capped at 20 MB.
bench get-app https://github.com/EffizienzAgent/davsync --branch version-16
bench --site <site> install-app davsyncCompatibility: Frappe v16 (Python 3.14). The version-16 branch always points to the latest release; tagged
releases and the changelog are on the releases page.
- Open CardDAV Account and add the server URL, user name and an app password. The account's Owner User owns imported contacts and events.
- Click Find address book (or enter the address book URL), tick Enabled, then Start initial import. Leave Push Enabled on for two-way sync.
- For the calendar, set Calendar Name or leave it empty, click Calendar → Find calendar, tick Calendar Sync Enabled and Start calendar import.
- Optional: DAV Sync Settings sets the default country of addresses, the phone region for numbers without a country code, your own e-mail addresses, which never count as attendees, and the sync intervals for contacts and the calendar.
The scheduler syncs every five minutes by default and refreshes recurring series daily. Incremental runs use sync tokens, so short intervals are cheap.
See docs/nextcloud.md for a Nextcloud walk-through and docs/extending.md for linking contacts and events to your own doctypes.
- A card that is already linked updates its contact.
- A new card adopts an existing contact with the same e-mail address, then a contact with the same
name linked to the same record (see
contact_linkin docs/extending.md). Otherwise a new contact is created. - A card deleted on the server archives the contact (
archived), it is never deleted. - Archiving a contact or ticking Exclude from address book removes the card from the server.
- Saving a contact pushes it right away. The scheduled run catches up on anything missed and picks up new contacts once the first pull has finished.
bench --site your.site set-config allow_tests true
bench --site your.site run-tests --app davsyncSet DAVSYNC_TEST_SERVER=http://localhost:5232 (user test, password test) to run the live
tests against Radicale as well; the CI does this.
MIT, see LICENSE. Frappe is a trademark of Frappe Technologies; this project is not affiliated with it.
Need help setting this up or integrating it into your Frappe stack? Write to oss@effizienzagent.de (English or German). German-speaking SMEs: see mittelstandshub.de.