Rails’ Component Libraries

Rails is made up of several components that all have specific jobs in making your Rails application work. Here’s a quick list of what they are and what they do.

ActionMailer - The basis for mailers. This is the library that allows you to format and send emails from your rails application
ActionPack - The components that parse, delegate, and render responses for requests.

ActionDispatch - Parses HTTP requests and sends the requests to controllers.
ActionController - Basis for Controllers -Takes requests and request parameters and gathers data to render a response.
ActionView - Basis for Views. Determines which template to use and builds the response to the HTTP request from the templates based on data provided by the Controller.

ActiveModel - Defines an interface on non-ActiveRecord classes that helps the behave like ActiveRecord models.
ActiveRecord - Basis for Models. Manages the connection between the Rails application and a SQL database. Provides means of querying