"icat", just cat ical data written in Ruby

icat.rb

#! /usr/bin/env ruby

require 'rubygems'
require 'vpim/icalendar'
require 'open-uri'
require 'optparse'
$KCODE = 'u'

class Icat
  def initialize
    @ics = []
  end

  def run
    opt = define_options
    opt.parse!( ARGV )
    takein_args( ARGV )
    if ( @ics.size > 0 )
      publish( fetch( @ics ) )
    else
      puts opt.help
    end
  end

  def define_options
    opt = OptionParser.new
    opt.on( '-l', '--list-from-file FILE' ) { |f|
      open( f ).each { |e|
        @ics << e.chomp
      }
    }
    opt.banner = "Usage: icat [options] ICS_FILES"

    return opt
  end

  def takein_args( argv )
    argv.each { |f|
      @ics << f
    }
  end

  def fetch( urls )
    cals = []

    if ( !urls.is_a?( Enumerable ) )
      urls = [ urls ]
    end
    urls.each { |url|
      Vpim::Icalendar::decode( open( url ).read ).each { |c|
        cals << c
      }
    }

    return cals
  end

  def publish( cals )
    cal = Vpim::Icalendar.create

    cals.each { |c|
      c.events.each { |e|
        cal << e
      }
    }

    puts cal.to_s
  end
end

if ( __FILE__ == $0 )
  Icat.new.run
end