iCalendar – Internet calendaring, Ruby style

This is a Ruby library for dealing with iCalendar files. Rather than explaining myself, here is the introduction from RFC-2445, which defines the format:

The use of calendaring and scheduling has grown considerably in the last decade. Enterprise and inter-enterprise business has become dependent on rapid scheduling of events and actions using this information technology. However, the longer term growth of calendaring and scheduling, is currently limited by the lack of Internet standards for the message content types that are central to these knowledgeware applications. This memo is intended to progress the level of interoperability possible between dissimilar calendaring and scheduling applications. This memo defines a MIME content type for exchanging electronic calendaring and scheduling information. The Internet Calendaring and Scheduling Core Object Specification, or iCalendar, allows for the capture and exchange of information normally stored within a calendaring and scheduling application; such as a Personal Information Manager (PIM) or a Group Scheduling product.

The iCalendar format is suitable as an exchange format between applications or systems. The format is defined in terms of a MIME content type. This will enable the object to be exchanged using several transports, including but not limited to SMTP, HTTP, a file system, desktop interactive protocols such as the use of a memory- based clipboard or drag/drop interactions, point-to-point asynchronous communication, wired-network transport, or some form of unwired transport such as infrared might also be used.

Now for some examples:

## Probably want to start with this

require 'rubygems' # Unless you install from the tarball or zip.
require 'icalendar'
require 'date'

include Icalendar # Probably do this in your class to limit namespace overlap

## Creating calendars and events is easy.

# Create a calendar with an event (standard method)
cal = Calendar.new
cal.event do
  dtstart       Date.new(2005, 04, 29)
  dtend         Date.new(2005, 04, 28)
  summary     "Meeting with the man."
  description "Have a long lunch meeting and decide nothing..."
  klass       "PRIVATE"
end

## Or you can make events like this

event = Event.new
event.start = DateTime.civil(2006, 6, 23, 8, 30)
event.summary = "A great event!"
cal.add_event(event)

event2 = cal.event  # This automatically adds the event to the calendar
event2.start = DateTime.civil(2006, 6, 24, 8, 30)
event2.summary = "Another great event!"

# Now with support for property parameters
params = {"ALTREP" =>['"http://my.language.net"'], "LANGUAGE" => ["SPANISH"]}

cal.event do
  dtstart Date.new(2005, 04, 29)
  dtend   Date.new(2005, 04, 28)
  summary "This is a summary with params.", params
end

# We can output the calendar as a string to write to a file, 
# network port, database etc.
cal_string = cal.to_ical
puts cal_string

Parsing iCalendars:

# Open a file or pass a string to the parser
cal_file = File.open("single_event.ics")

# Parser returns an array of calendars because a single file
# can have multiple calendars.
cals = Icalendar.parse(cal_file)
cal = cals.first

# Now you can access the cal object in just the same way I created it
event = cal.events.first

puts "start date-time: " + event.dtstart
puts "summary: " + event.summary

Finders:

Often times in web apps and other interactive applications you’ll need to lookup items in a calendar to make changes or get details. Now you can find everything by the unique id automatically associated with all components.

cal = Calendar.new
10.times { cal.event } # Create 10 events with only default data.
some_event = cal.events[5] # Grab it from the array of events

# Use the uid as the key in your app
key = some_event.uid

# so later you can find it.
same_event = cal.find_event(key)

Examples:

Check the unit tests for examples of most things you’ll want to do, but please send me example code or let me know what’s missing.

Download

The latest release version of this library can be found at

rubyforge.org/projects/icalendar/

Documentation can be found at

icalendar.rubyforge.org/

Installation

It’s all about rubygems:

$ sudo gem install icalendar

License

This library is released under the same license as Ruby itself.

Support & Contributions

The iCalendar library homepage is icalendar.rubyforge.org/

There is an [email protected] mailing list that can be used for asking questions, making comments or submitting patches.