What is a Ruby Gem?

Ruby is a dynamic, reflectiveIn programming, "reflective" in Ruby means the language can look at and change its own structure and behavior while running., object-oriented programming language. Ruby is known for its syntax, which focuses on readability and simplicity. It has a strong community, and many open-source projects and libraries have been created using Ruby. The following are some of the key features of Ruby:

Ruby gem

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:

To install a specific version of a gem, we add the version number after the gem name:

To install gems listed in a project’s Gemfile (common in Ruby projects), we use the bundler gem. This is similar to npmnode package manager, which is used to install node modules or packages within Node.js projects. Once the 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:

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:

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 list command 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 the cat /Gemfile command 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:

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:

In the code snippet above:

• Line 1: We import the json gem.

• Lines 3–7: We define a Ruby hash named data with various key-value pairs.

• Lines 9–11: We use the json gem to convert the Ruby hash data to a JSON string format. Finally, we print the JSON string data.

• Lines 13–15: We use the json gem 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.