EDS4S - Evolution Data Server for Scala

A Scala 3 library for GNOME Evolution Data Server via DBus.

What is it?

EDS4S is a type-safe, functional Scala 3 library for managing calendars and events on Linux systems. It communicates with GNOME's Evolution Data Server through DBus, giving your Scala apps native calendar integration.

Purpose

Type-safe calendar and event management for Scala applications running on Linux desktops. Perfect for building scheduling apps, calendar tools, or any software that needs to read or write calendar data.

Prerequisites

JVM

• Java 17+, Scala 3.3.x, sbt 1.9.x
• Evolution Data Server (installed and running)

# Ubuntu/Debian
sudo apt install evolution-data-server
# Fedora  
sudo dnf install evolution-data-server
# Arch Linux
sudo pacman -S evolution-data-server

Scala Native

• Scala Native 0.5.x, sbt 1.9.x
• Evolution Data Server (same as JVM)
• Native toolchain: clang, lld, libunwind-dev, libgc-dev
• libdbus-1 development files (for DBus FFI bindings)

# Ubuntu/Debian
sudo apt install evolution-data-server libdbus-1-dev clang lld libunwind-dev libgc-dev

# Fedora  
sudo dnf install evolution-data-server dbus-devel clang lld libunwind-devel libgc-devel

# Arch Linux
sudo pacman -S evolution-data-server dbus clang lld libunwind libgc

Installation

// For JVM
libraryDependencies += "org.polyvariant" %% "eds4s-core" % "0.1.0"
libraryDependencies += "org.polyvariant" %% "eds4s-dbus" % "0.1.0"

// For Scala Native
libraryDependencies += "org.polyvariant" %%% "eds4s-core" % "0.1.0"
libraryDependencies += "org.polyvariant" %%% "eds4s-dbus" % "0.1.0"

Quick Start

import eds4s.*, eds4s.dbus.DBusCalendarClient
import cats.effect.*, cats.syntax.all.*
import java.time.Instant

object QuickStart extends IOApp.Simple {
  def run: IO[Unit] = 
    DBusCalendarClient.resource[IO].use { client =>
      for
        calendars <- client.listCalendars
        _ <- IO.println(s"Found ${calendars.size} calendars")
        
        calendar <- client.createCalendar(
          name = "My Calendar", backend = CalendarBackend.Local,
          calendarType = CalendarType.Events, color = Some("#3465A4"))
        
        now <- IO(Instant.now())
        eventId <- client.createEvent(calendar.uid, EventData(
          summary = "Team Meeting", description = Some("Weekly sync"),
          location = Some("Room A"), startTime = now.plusSeconds(3600),
          endTime = Some(now.plusSeconds(7200)), timeZone = Some("Europe/Warsaw")))
        
        events <- client.getEvents(calendar.uid)
        _ <- IO.println(s"Events: ${events.map(_.summary).mkString(", ")}")
        
        _ <- client.deleteEvent(calendar.uid, eventId)
        _ <- client.deleteCalendar(calendar.uid)
      yield ()
    }
}

Common Operations

List Calendars

calendars <- client.listCalendars
calendars.foreach(c => println(s"${c.name} (${c.uid})"))

Create Calendar

calendar <- client.createCalendar(
  name = "Work", backend = CalendarBackend.Local,
  calendarType = CalendarType.Events, color = Some("#FF5500"))

Create Event

eventId <- client.createEvent(calendarUid, EventData(
  summary = "Meeting",
  startTime = Instant.parse("2024-03-15T10:00:00Z"),
  endTime = Some(Instant.parse("2024-03-15T11:00:00Z"))))

Query Events

// All events
events <- client.getEvents(calendarUid, EventQuery.all)

// By text search
events <- client.getEvents(calendarUid, EventQuery.contains("meeting"))

// By time range
events <- client.getEvents(calendarUid, 
  EventQuery.inRange(Instant.parse("2024-03-01T00:00:00Z"),
                     Instant.parse("2024-03-31T23:59:59Z")))

Delete Event/Calendar

client.deleteEvent(calendarUid, eventId, ModificationType.This)
client.deleteCalendar(calendarUid)

API Overview

CalendarClient[F[_]] is the main interface:

• Calendar ops: listCalendars, getCalendar, createCalendar, deleteCalendar
• Event ops: getEvents, getEvent, createEvent, modifyEvent, deleteEvent

Key types: CalendarInfo, Event, EventData, EventQuery, EventId

Examples

sbt "examples/runMain eds4s.examples.QuickStart"

Building & Testing

sbt compile                    # Compile all modules
sbt coreJVM/test               # Core JVM tests (no EDS required)
sbt coreNative/test            # Core Native tests (no EDS required)  
sbt dbusJVM/test               # DBus JVM integration tests (requires EDS)
sbt dbusNative/test            # DBus Native tests (requires EDS + libdbus)

Scala Native Support

EDS4S supports both JVM and Scala Native platforms:

• core: Cross-compiled for JVM and Native

  • JVM uses ical4j for ICS parsing
  • Native uses a pure Scala ICS parser

• dbus: Cross-compiled for JVM and Native

  • JVM uses dbus-java library
  • Native uses libdbus-1 FFI bindings

Native Dependencies

On Debian/Ubuntu:

sudo apt install libdbus-1-dev clang lld libunwind-dev libgc-dev

On Fedora:

sudo dnf install dbus-devel clang lld libunwind-devel libgc-devel

On Arch Linux:

sudo pacman -S dbus clang lld libunwind libgc

License

Apache 2.0