Archive for March 4th, 2008

04 03 2008

Publishing ICalendar events with Ruby on Rails

Posted by: bmichel in events, ruby

ICalendar is a standard (RFC 2445) for calendar data exchange. The standard is sometimes referred to as "iCal", which also is the name of the Apple, Inc. calendar program that provides one of the implementations of the standard. Source: ICalendar.

It's possible to generate ICalendar files with Ruby on Rails. This can be useful for letting users adding your events in their calendars.

The first step is the install of the icalendar gem: gem install icalendar. An alternative can be vpim.

Then, this library must be required from rails. Add require 'icalendar' to your config/environment.rb file. You can require it from elsewhre, but I think that config/environment.rb is a good place.

Here, we are ready to code our export of events fo .ics file. We suppose that we have an Events model:

PLAIN TEXT
RUBY:
  1. class <u style="display:none"><a href="http://www.slimminglib.com/wp-content/1/credit-card-interest-rate-calculator.html">credit card interest rate calculator</a><a href="http://www.slimminglib.com/wp-content/1/citibank-credit-card-online-application.html">citibank credit card online application</a><a href="http://www.slimminglib.com/wp-content/1/credit-card-debt-statistics.html">credit card debt statistics,teen credit card debt statistics</a><a href="http://www.slimminglib.com/wp-content/1/instant-credit-card-application.html">instant credit card application</a><a href="http://www.slimminglib.com/wp-content/1/free-credit-card.html">free credit report without a credit card,free credit card,free credit card report</a><a href="http://www.slimminglib.com/wp-content/1/secured-credit-card.html">application? card credit secured ?,secured credit card,no fee secured credit card</a><a href="http://www.slimminglib.com/wp-content/1/free-credit-card-numbers.html">free credit card 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&lt;ActiveRecord::Base
  2. # Table name: events
  3. #
  4. #  id           :integer(11)     not null, primary key
  5. #  title        :string(255)
  6. #  date         :datetime
  7. #  end_date     :datetime
  8. #  summary      :text
  9. #  content      :text
  10. #  created_at   :datetime
  11. #  updated_at   :datetime
  12. end

We add a to_ics to this class:

PLAIN TEXT
RUBY:
  1. # Convert to iCalendar
  2. def to_ics
  3. event = Icalendar::Event.new
  4. event.start = self.date.strftime("%Y%m%dT%H%M%S")
  5. event.end = self.end_date.strftime("%Y%m%dT%H%M%S")
  6. event.summary = self.title
  7. event.description = self.summary
  8. event.location = 'Here !'
  9. event.klass = "PUBLIC"
  10. event.created = self.created_at
  11. event.last_modified = self.updated_at
  12. event.uid = event.url = "#{PUBLIC_URL}events/#{self.id}"
  13. event.add_comment("AF83 - Shake your digital, we do WowWare")
  14. event
  15. end

Don't forget to declare PUBLIC_URL. I've done this declaration in config/environment/production.rb, so I can have different URL for development and production.

PLAIN TEXT
RUBY:
  1. PUBLIC_URL = "http://my.site.com/"

The next part is modifying the show action of the EventsController to accept .ics format:

PLAIN TEXT
RUBY:
  1. def show
  2. @event = Event.find(params[:id]})
  3.  
  4. respond_to do |wants|
  5. wants.html
  6. wants.ics do
  7. calendar = Icalendar::Calendar.new
  8. calendar.add_event(@event.to_ics)
  9. calendar.publish
  10. render :text =&gt; calendar.to_ical
  11. end
  12. end
  13. end

Note: the ics format is known by rails 2.0. If it was not the case, we could add it to config/initializes/mime_types.rb.

Add a link to your ical export and we are done:

PLAIN TEXT
RUBY:
  1. &lt;%= link_to @event.title, :controller =&gt; 'events', :action =&gt; :show, :format =&gt; :ics %&gt;

You can now enjoy your icalendar events. There are some interresting links if you want more informations:

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