Beefcake (A sane Google Protocol Buffers library for Ruby)

It's all about being Buf; ProtoBuf.

Install

$ gem install beefcake

Example

require 'beefcake'

class Variety
  include Beefcake::Message

  # Required
  required :x, :int32, 1
  required :y, :int32, 2

  # Optional
  optional :tag, :string, 3

  # Repeated
  repeated :ary,  :fixed64, 4
  repeated :pary, :fixed64, 5, :packed => true

  # Enums - Simply use a Module (NOTE: defaults are optional)
  module Foonum
    A = 1
    B = 2
  end

  # As per the spec, defaults are only set at the end
  # of decoding a message, not on object creation.
  optional :foo, Foonum, 6, :default => Foonum::B
end

x = Variety.new :x => 1, :y => 2
# or
x = Variety.new
x.x = 1
x.y = 2

Encoding

Any object responding to << can accept encoding

s = ""
x.encode(s)
p [:s, s]
# or (because encode returns the string/stream)
p [:s, x.encode]
# or
open("x.dat") do |f|
  x.encode(f)
end

# decode
encoded = x.encode
decoded = Variety.decode(encoded)
p [:x, decoded]

# decode merge
Variety.decoded(more_data, decoded)

Why?

Ruby deserves and needs first-class ProtoBuf support. Other libs didn't feel very "Ruby" to me and were hard to parse.

Generate code from .proto file

$ protoc --beefcake_out output/path -I path/to/proto/files/dir path/to/proto/file

You can set the BEEFCAKE_NAMESPACE variable to generate the classes under a desired namespace. (i.e. App::Foo::Bar)

Misc

This library was built with EventMachine in mind. Not just blocking-IO.

Dev

Source:

$ git clone git://github.com/bmizerany/beefcake

Testing:

$ gem install turn
$ cd /path/to/beefcake
$ turn

VMs:

Currently Beefcake is tested and working on:

• Ruby 1.8.6
• Ruby 1.8.7
• Ruby 1.9.2
• JRuby 1.5.6
• Rubinius edge

Support Features

• Optional fields
• Required fields
• Repeated fields
• Packed Repeated Fields
• Varint fields
• 32-bit fields
• 64-bit fields
• Length delemited fields
• Embeded Messages
• Unknown fields are ignored (as per spec)
• Enums
• Defaults (i.e. optional :foo, :string, :default => "bar")

Future

• Imports
• Use package in generation
• Groups (would be nice for accessing older protos)

Further Reading

http://code.google.com/apis/protocolbuffers/docs/encoding.html

Thank You

Keith Rarick (kr) for help with encoding/decoding. Aman Gupta (tmm1) for help with cross VM support and performance enhancements.