ex_dav

⚠️ Beta / heavy WIP. APIs are unstable and may change between releases. Not yet recommended for production use.

CalDAV server library for Elixir. Mounts as a Plug under any host application. Ships with a Postgres-backed reference adapter and an in-memory adapter; bring your own for arbitrary backends.

Passes 57/57 of the caldav_client integration suite as of v0.3.0.

plug ExDav.CalDav.Plug,
  storage: ExDav.Storage.Postgres,
  authenticator: {ExDav.Authenticator.Basic,
                  verify: {ExDav.Storage.Postgres, :authenticate}}

What you get

• ExDav.CalDav.Plug — handles PROPFIND, REPORT, MKCALENDAR, PROPPATCH, PUT, GET, DELETE under /dav/... plus the RFC 6764 .well-known/caldav redirect. Other paths pass through untouched.
• ExDav.Storage — behaviour for storage adapters. Adapters return plain maps so the protocol layer stays ORM-agnostic.
• ExDav.Storage.Postgres — reference adapter using Ecto. Owns its own users / calendars / objects / tombstones tables; reads its Ecto.Repo from Application.fetch_env!(:ex_dav, :repo).
• ExDav.Storage.Memory — in-memory adapter (Agent-backed) for dev demos and tests.
• ExDav.Authenticator — behaviour for HTTP authenticators. ExDav.Authenticator.Basic ships HTTP Basic with a configurable :verify MFA tuple.

Usage in a Phoenix app

# config/config.exs
config :ex_dav, repo: MyApp.Repo

# lib/my_app_web/endpoint.ex
plug ExDav.CalDav.Plug,
  storage: ExDav.Storage.Postgres,
  authenticator: {ExDav.Authenticator.Basic,
                  verify: {ExDav.Storage.Postgres, :authenticate}}

The Postgres adapter ships migrations in priv/repo/migrations of this package. Either copy them into your host app's migrations directory, or point Ecto at them via --migrations-path:

mix ecto.migrate --migrations-path deps/ex_dav/priv/repo/migrations

It creates four tables prefixed caldav_* (caldav_users, caldav_calendars, caldav_calendar_objects, caldav_calendar_object_tombstones) so they don't clash with host-app tables.

Breaking change in v0.2.0: tables were renamed from users, calendars, calendar_objects, calendar_object_tombstones to caldav_* for namespacing. Drop and re-run migrations, or rename manually.

Custom storage adapter

defmodule MyApp.CalDavStorage do
  @behaviour ExDav.Storage

  @impl true
  def list_calendars(username) do
    # return [%{name:, displayname:, description:, components:, ctag:, objects:}]
  end

  @impl true
  def put_object(username, cal_name, obj_name, ical), do: ...

  # ...all 11 callbacks
end

Then mount:

plug ExDav.CalDav.Plug,
  storage: MyApp.CalDavStorage,
  authenticator: {MyApp.CalDavAuth, []}

Custom authenticator

defmodule MyApp.CalDavAuth do
  @behaviour ExDav.Authenticator

  @impl true
  def authenticate(conn, _opts) do
    case extract_token(conn) do
      {:ok, principal} -> {:ok, conn, principal}
      :error -> :unauth
    end
  end
end

Standalone

For a runnable reference deployment, see apps/ex_dav_server in this repository — a minimal Phoenix app that wires the library to Postgres and ships an admin LiveView for managing CalDAV principals.

License

GNU General Public License v3.0 or later (GPL-3.0-or-later). See LICENSE.