#sequel-protobuf

##what

A plugin for the sequel database library that enables Sequel::Model classes to be serialized into protocol buffers.

##documentation

Documentation can be found here.

##installation

There is an intent to have this gem available through rubygems eventually, but for now, it's easiest to require the gem through bundler by specifying it in your Gemfile:

Gemfile

gem 'sequel-protobuf', :git => "git@github.com/kellydunn/sequel-protobuf"

##usage

In your Sequel::Model definition, require sequel, sequel-protobuf, a protocol buffer utility library of your choice (like ruby-protocol-buffers), and the corresponding protocol buffer model definition (the .pb.rb file that ruby-protoc generates). Next, specify that you want your Sequel::Model class to use the protobuf plugin along with the class name of the protobuf model definition, like so:

require 'sequel'
require 'sequel/plugins/protobuf'
require 'protocol_buffers'
require 'your/protocol/buffer/definitions/my_model_definition'

class MyModel < Sequel::Model
  plugin :protobuf, :model => MyModelDefinition
end

Now you can create a new instance of your record, and call to_protobuf or from_protobuf on it!

Simple Sequel::Dataset operations will also work as well!

5.times do 
  MyModel.create()
end

result = MyModel.all.to_protobuf
# result is an array of protocol buffer representations of each instance of {MyModel}!

##configuration

As of 0.2.0, sequel-protobuf provides the ability to render nested protocol buffer models, re-format data-types on demand, and override default protocol buffer definitions while rendering. To do this, you may supply an options hash to the to_protobuf and as_protobuf methods with any of the following keys:

• :include: specifies nested protocol buffer models to render
• :as: specifies a different protocol buffer model definition in which to render the current object as
• :coerce: specifies how to re-format a specific data column of the current Sequel::Model such that it can fit your protocol buffer definition.

###Example

require 'sequel'
require 'sequel/plugins/protobuf'
require 'protocol_buffers'
require 'your/protocol/buffer/definitions/my_model_definition'

class MyModel < Sequel::Model
  plugin :protobuf, :model => MyModelDefinition
  one_to_many :nested

  def app_specific_as_protobuf
    config = {
      :as => DifferentModelDefinition,
      :include => {
        :nested => {}
      }
      :coerce => {
        # We coerce the creatd_at time since Protocol Buffers
        # do not support Time types by default.
        # The reccomended approach is to set the unix timestamp value
        # as a int64 type.
        :created_at => Proc.new { |created_at|
          created_at.utc.to_i
        }
      }
    }

    return self.as_protobuf(config)
  end
end

##considerations

• This library currently only supports ruby-protocol-buffers as a serialization driver. If you are interested in adding additional driver support, feel free to open a Pull Request!