RocketAMF can de/serialize AMF serialized byte streams, but it throws (at least, the 0.2.1 version from gem install throws) when it encounters an IExternalizable type in the byte steam. This patch allows it to parsed custom IExternalizable classes properly.

print_amf.rb

#!/usr/bin/env ruby
 
require 'rocketamf'
require 'stringio'
 
# Monkey patch for RocketAMF (0.2.1 gem) that handles IExrternalizable types
# in the input, storing their type as "__as3_type" parameter:
module RocketAMF
  module Values #:nodoc:
    class TypedHash
 
      def externalized_data= obj
        obj.each { |k,v|
          self[k] = v
        }
        self["__as3_type"] = @type
      end
 
    end
  end
end
 
if (ARGV.length==0) then
  puts "usage: print_amf.rb <infile.amf>"
  exit
end

# And a little command-line utility for printing AMF as JSON
require 'json'
 
puts JSON.pretty_generate RocketAMF.deserialize(File.read(ARGV[0]), 3)

to_amf.rb

#!/usr/bin/env ruby
# Utility to convert .json or .yaml files to .amf

require 'json'
require 'yaml'
require 'rocketamf'

infile = ARGV[0]
outfile = ARGV[1]

if (infile==nil || outfile==nil) then
  puts "usage: to_amf.rb <json_or_yaml_file> <outfile.amf>"
  exit
end

if (infile.match(/\.yaml$/)) then
  File.open(outfile, 'wb') { |file| file.write RocketAMF.serialize(YAML.load(IO.read(infile)), 3) }
elsif (infile.match(/\.json$/)) then
  File.open(outfile, 'wb') { |file| file.write RocketAMF.serialize(JSON.parse(IO.read(infile)), 3) }
end