Play around with CBOR for Time and DateTime in Ruby

cbor-date-time.rb

#!/usr/bin/env ruby
require 'cbor'

# Assume that the cbor-diag gem is installed, but don't use it directly
def pretty(item)
  IO.popen("cbor2pretty.rb", "wb") {|io| io.write(item)}
end

puts "# Show that the default Time representation is Tag 1"
t = Time.now
p t
pretty t.to_cbor

require 'date'

puts "# Make us a DateTime out of that Time"
dt = t.to_datetime
p dt
puts dt.to_s

puts "# Out of the box, to_cbor fails for DateTime"
begin
  pretty dt.to_cbor
rescue => e
  p e
end

# This module can be used to define to_cbor for Date
module DateTimeAsRfc3337
  def to_cbor
    CBOR::Tagged.new(0, rfc3339).to_cbor
  end
end

puts "# So let's make us a module DateTimeAsRfc3337 and extend with that"
dt.extend(DateTimeAsRfc3337)
pretty dt.to_cbor
puts "# Show how a different timezone is serialized"
pretty dt.new_offset.extend(DateTimeAsRfc3337).to_cbor

# This module can be used to define to_cbor for anything that supports to_datetime
module TimeAsRfc3337
  def to_cbor
    CBOR::Tagged.new(0, to_datetime.rfc3339).to_cbor
  end
end

puts "# ... and a module TimeAsRfc3337 and extend the Time object with that"
t.extend(TimeAsRfc3337)
pretty t.to_cbor