Create Your Gem Project

Ruby Gems

A RubyGem is a software package, commonly called a “gem”. Gems contain a packaged Ruby application or library. The RubyGems software itself allows you to easily download, install, and manipulate gems on your system.

Each gem has a name, version and platform. They are used to split out reusable functionality so others can use.

Structure

• Code (include test and utils)
• Documentation
• gemspec

Gems follow the same standard structure of code organization:

% tree mygem
mygem/
├── bin/
│   └── mygem
├── lib/
│   └── mygem.rb
├── test/
│   └── test_mygem.rb
├── README
├── Rakefile
└── mygem.gemspec

The major components of a gem:

• lib directory with source code
• test or spec for tests
• Rakefile for automation of test, generate code and other tasks
• bin with a executable file that is installed in PATH
• Documentation is usually included in the README and inline with the code (RDocs or YARD)
• gemspec contains information about the gem.

The Gempsec

Use to document details about the gem, who made, what the purpose, dependencies, authors and other information.

$ cat mygem.gemspec
Gem::Specification.new do |s|
  s.name        = 'mygem'
  s.version     = '1.0.0'
  s.date        = '2013-04-20'
  s.summary     = "My Gem!"
  s.description = "My Gem is a Gem!"
  s.authors     = ["Emiliano Firmino"]
  s.email       = 'emiliano.firmino@gmail.com'
  s.homepage    = 'http://mypage.com.br'
  s.files       = ["lib/mygem.rb"]
end

Using Bundler to Create Your Gem

See RailsCasts #245: New gem with Bundler

References

How to Create a Gem From Scratch With Bundler
How To Start Writing a Ruby Gem
Make Your Own Gem Making Ruby Gems
RailsCasts #245: New gem with Bundler
What Is a Gem