What is a Ruby Gem?
Ruby is a dynamic,
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Ruby follows the principles of object-oriented programming.
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Ruby is dynamically typed, meaning that variable types are determined at runtime.
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Ruby includes automatic garbage collection, which manages memory and deallocates objects that are no longer in use.
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Ruby is free and open-source, and its source code is available for modification and distribution.
Ruby gem
A Ruby gem is a packaged and shareable piece of software or library written in the Ruby programming language. It typically contains reusable code, and developers use gems to easily integrate and share functionality in Ruby applications. RubyGems, the package manager for Ruby, facilitates the installation, management, and distribution of these gems.
Note: RubyGems comes pre-installed when we do a fresh installation of Ruby.
Gems can provide various functionalities to Ruby applications. Gems are used to extend Ruby's capabilities by adding libraries and tools. Here are some common things gems can do:
Library and tool distribution: Gems are a convenient way to distribute and share Ruby libraries, tools, and applications.
Dependency management: Gems can specify dependencies on other gems, ensuring that the required versions of libraries are available.
Command-line tools: Some gems provide command-line tools that can be easily executed from the terminal, enhancing developer productivity.
Testing: Gems can provide testing frameworks and utilities to help developers write and run tests for their code.
Data processing: Gems can assist in data manipulation, processing, and analysis, offering solutions for common tasks.
Web development: Many gems are designed for web development and work seamlessly with web frameworks like Ruby on Rails. Examples include authentication gems and database connectors.
Popular gems
Ruby has various gems that are used for all sorts of tasks and functionalities. Some popular and widely used gems in the Ruby ecosystem include:
rails: The Ruby on Rails framework is itself a gem, providing a robust structure for building web applications.devise: This is a popular gem that provides an authentication solution for Rails applications.nokogiri: This is a gem for parsing and working with XML and HTML documents.dotenv: This is a gem for loading environment variables from a file, commonly used in Rails applications.bundler: This is a gem for managing gem dependencies in Ruby projects. It allows us to specify and install the exact versions of gems our project needs.json: This is a gem that facilitates encoding (serialization) and decoding (deserialization) of JSON data.
Installing and uninstalling gems
To install a Ruby gem, we use the gem install command followed by the gem’s name. For example, the following command will be used to install the nokogiri gem:
gem install nokogiri
To install a specific version of a gem, we add the version number after the gem name:
gem install nokogiri -v 1.12.5
To install gems listed in a project’s Gemfile (common in Ruby projects), we use the bundler gem. This is similar to bundler gem has been installed, we use the following command within the Ruby project to install all gems that are listed in a project’s Gemfile:
bundle install
To uninstall a gem, we use the gem uninstall command followed by the gem’s name. For example, the following command will be used to uninstall the nokogiri gem:
gem uninstall nokogiri
Note that when a gem is uninstalled, we have to manually remove it from the relevant Gemfile as well. Otherwise, the bundler will install the gem again if the bundle install command is executed.
Note: The
gem listcommand can be used to see a list of all the installed gems and their versions.
Use the terminal below to execute the commands mentioned above and see the resulting output.
Note: A sample Gemfile has already been provided to you within the
/directory. Use thecat /Gemfilecommand to see the contents of the Gemfile.
Using gems
Once the gems have been installed, we can use them within Ruby projects. To do so, we have to import the necessary gems within the Ruby file. We use the require keyword to import gems within a Ruby file. The code snippet below shows how to import the json gem within a Ruby file:
require 'json'
Once the gem has been imported, we can utilize its functionality.
Try it yourself
The coding playground below shows how to use the json gem within a Ruby file:
require 'json'
data = {
"name" => "John",
"age" => 30,
"city" => "New York"
}
json_string_format = JSON.generate(data)
puts "JSON String Format:"
puts json_string_format
ruby_hash = JSON.parse(json_string_format)
puts "\nRuby Hash:"
puts ruby_hashIn the code snippet above:
Line 1: We import the
jsongem.Lines 3–7: We define a Ruby hash named
datawith various key-value pairs.Lines 9–11: We use the
jsongem to convert the Ruby hashdatato a JSON string format. Finally, we print the JSON string data.Lines 13–15: We use the
jsongem to convert the JSON string format back to Ruby hash. Finally, we print the Ruby hash.
Conclusion
In conclusion, Ruby gems play a pivotal role in expanding the functionality of Ruby projects, offering a vast ecosystem of libraries and tools. Popular gems like json, nokogiri, and bundler streamline development tasks and simplify dependency management. The ease of installing and uninstalling gems empowers developers to efficiently integrate and leverage these resources, fostering a dynamic and collaborative Ruby community.
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