protobuf/ruby/README.md

This directory contains the Ruby extension that implements Protocol Buffers functionality in Ruby.

The Ruby extension makes use of generated Ruby code that defines message and enum types in a Ruby DSL. You may write definitions in this DSL directly, but we recommend using protoc's Ruby generation support with .proto files. The build process in this directory only installs the extension; you need to install protoc as well to have Ruby code generation functionality.

Installation from Gem

When we release a version of Protocol Buffers, we will upload a Gem to RubyGems. To use this pre-packaged gem, simply install it as you would any other gem:

$ gem install [--prerelease] google-protobuf

The --pre flag is necessary if we have not yet made a non-alpha/beta release of the Ruby extension; it allows gem to consider these "pre-release" alpha/beta versions.

Once the gem is installed, you may or may not need protoc. If you write your message type descriptions directly in the Ruby DSL, you do not need it. However, if you wish to generate the Ruby DSL from a .proto file, you will also want to install Protocol Buffers itself, as described in this repository's main README file. The version of protoc included in the latest release supports the --ruby_out option to generate Ruby code.

A simple example of using the Ruby extension follows. More extensive documentation may be found in the RubyDoc comments (call-seq tags) in the source, and we plan to release separate, more detailed, documentation at a later date.

require 'google/protobuf'

# generated from my_proto_types.proto with protoc:
#  $ protoc --ruby_out=. my_proto_types.proto
require 'my_proto_types'

mymessage = MyTestMessage.new(:field1 => 42, :field2 => ["a", "b", "c"])
mymessage.field1 = 43
mymessage.field2.push("d")
mymessage.field3 = SubMessage.new(:foo => 100)

encoded_data = MyTestMessage.encode(mymessage)
decoded = MyTestMessage.decode(encoded_data)
assert decoded == mymessage

puts "JSON:"
puts MyTestMessage.encode_json(mymessage)

Installation from Source (Building Gem)

To build this Ruby extension, you will need:

• Rake
• Bundler
• Ruby development headers
• a C compiler

First, install the required Ruby gems:

$ sudo gem install bundler rake rake-compiler rspec rubygems-tasks

Then build the Gem:

$ rake gem
$ gem install pkg/protobuf-$VERSION.gem

This gem includes the upb parsing and serialization library as a single-file amalgamation. It is up-to-date with upb git commit 535bc2fe2f2b467f59347ffc9449e11e47791257.