While learning about Ruby gems you may also read about Bundler.īundler is a tool for dependency management. Then you can package the gem using gem build. Once you’ve changed the summary & description from the default values… you’ll able to load an irb session with your gem using the bin/console program that bundle gem creates for you. While add_dependency defines gems that you use as part of your code. These are gems like minitest, RSpec, or pry. The add_development_dependency lines define gems that you’re going to use during development. That’s the file that gets loaded when you require the gem!

You will have most of your requires in lib/.rb (the only file at the root of /lib). This allows you to put your code under lib// & then require it with require '/'.Ī file named lib/awesome_gem/parser.rb would be required as require 'awesome_gem/parser' from anywhere inside the gem. The require_paths array is where Ruby will look for your gem files when you require them. Spec.add_development_dependency 'minitest', '~> 5.0' Spec.add_development_dependency 'rake', '~> 10.0' Spec.add_development_dependency 'bundler', '~> 1.16' Spec.summary = 'Example gem for article about Ruby gems' The gem version itself is defined as a constant in lib//version.rb. Optional: Author’s email address, project URL (homepage), executables, c extensions, long description.gemspec file is where you’ll find all the information about the gem. Ī Gem is composed of the following structure: You can prepare the files for a new gem by running bundle gem. Let’s learn more about gems by building your own & looking at the files that make a gem. In some cases, you may need to manually install additional software that is not managed by RubyGems.

This extension is built automatically for you when you install the gem.

Rails, and all of its components (ActiveRecord, ActiveSupport, etc.) are distributed as Ruby gemsĪ few gems include a Ruby C extension for improved performance.

Thanks to RubyGems, we have a rich ecosystem of helpful libraries just one gem install away!Ī list of gems required for a given (non-gem) project can be listed on a special file called “Gemfile” so they can be automatically installed by Bundler.

A specification (“.spec”) file that comes with every gem describes dependencies (other required gems) so the code has everything it needs to work.

The file structure & format of a gem makes it easy to understand how they work.

It’s how we share libraries & tools in Ruby.

Easily work with external services (like APIs).

When you require an installed gem you’re adding extra functionality to your Ruby program. A gem is a package that you can download & install.

Rubymine format code