#301 Extracting a Ruby Gem pro

Nov 21, 2011 | 16 minutes | Testing, Plugins

In this episode I show how to extract a Ruby Gem from an existing Rails application, test it with RSpec and Supermodel, and add a Railtie.

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Resources

          bash
        
bundle gem url_formatter
bundle
echo "--color" > .rspec
mkdir -p spec/url_formatter
touch spec/spec_helper.rb
rake

          Rakefile
        
require 'rspec/core/rake_task'

RSpec::Core::RakeTask.new(:spec)

task default: :spec

          url_formatter.gemspec
        
s.add_development_dependency "rspec"
s.add_development_dependency "supermodel"

          spec/spec_helper.rb
        
require 'url_formatter'
require 'supermodel'

          spec/url_formatter/model_additions_spec.rb
        
class Comment < SuperModel::Base
  include ActiveModel::Validations::Callbacks
  extend UrlFormatter::ModelAdditions
  format_url :website
end

          lib/url_formatter.rb
        
require "url_formatter/model_additions"
require "url_formatter/railtie" if defined? Rails

          lib/url_formatter/model_additions.rb
        
module UrlFormatter
  module ModelAdditions
    def format_url(attribute)
      before_validation do
        send("#{attribute}=", UrlFormatter.format_url(send(attribute)))
      end
      validates_format_of attribute, with: UrlFormatter.url_regexp, message: "is not a valid URL"
    end
  end
end

          lib/url_formatter/railtie.rb
        
module UrlFormatter
  class Railtie < Rails::Railtie
    initializer 'url_formatter.model_additions' do
      ActiveSupport.on_load :active_record do
        extend ModelAdditions
      end
    end
  end
end

          Gemfile
        
gem 'url_formatter', path: '~/code/url_formatter'