Ruby gems are packages of code that extend or enhance Ruby's functionality. They're an essential part of the Ruby ecosystem, allowing developers to easily share and reuse code across projects.
Gems are self-contained Ruby libraries or applications. They include code, documentation, and a specification file. Gems simplify the process of distributing and managing Ruby software.
To use a gem in your Ruby project, you first need to install it. Then, you can require it in your code. Here's a simple example:
# Install the gem (in your terminal)
gem install nokogiri
# Use the gem in your Ruby file
require 'nokogiri'
# Now you can use Nokogiri's functionality
doc = Nokogiri::HTML('<html><body><h1>Hello, Gems!</h1></body></html>')
puts doc.at_css('h1').text
For larger projects, it's common to use Bundler to manage gem dependencies. Bundler ensures that you have the correct versions of all the gems your project needs.
bundle install
to install the gemsHere's an example Gemfile:
source 'https://rubygems.org'
gem 'nokogiri'
gem 'rack', '~> 2.2.4'
gem 'rspec', :group => :development
You can also create your own gems to share your code with others. The process involves:
Here's a basic structure for a gem:
my_gem/
├── lib/
│ └── my_gem.rb
├── test/
├── README.md
└── my_gem.gemspec
Ruby gems are a powerful tool for extending your Ruby applications and sharing code. By understanding how to use and manage gems, you can significantly enhance your productivity as a Ruby developer.
For more advanced topics related to gems, consider exploring Ruby Gem Installation and Ruby Bundler in depth.