Top 10 Ruby on Rails Design Patterns for Speed and Performance

Ruby on Rails design patterns are reusable solutions to common software design problems. They provide a structured approach to building robust and maintainable applications. Ruby on Rails is a full-stack web framework that encourages the use of design patterns.

Ruby on Rails Design Patterns

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In this article, we will discuss the top 10 Ruby on Rails design patterns and provide example code for each item.

1. Model-View-Controller (MVC)

The MVC pattern is the foundation of Rails application architecture. It separates the application into three distinct components:

• Model: Represents the data and business logic of the application.
• View: Handles the presentation and UI of the application.
• Controller: Acts as an intermediary, controlling the flow of data and requests between the Model and View.

The MVC pattern promotes the separation of concerns, maintainability, and code reusability.

Example Code:

# Model
class User < ApplicationRecord
  validates :name, presence: true
  validates :email, presence: true, uniqueness: true
end

# View
<% @users.each do |user| %>
  <h1><%= user.name %></h1>
  <p><%= user.email %></p>
<% end %>

# Controller
class UsersController < ApplicationController
  def index
    @users = User.all
  end
end

2. Active Record

The Active Record pattern is an object-relational mapping (ORM) pattern that provides an object-oriented interface for interacting with a relational database. It is the default ORM for Rails applications.

Active Record makes it easy to retrieve, manipulate, and persist data in the database. It also provides a number of features that make it easy to write complex queries and maintain data integrity.

Example Code:

# Model
class User < ApplicationRecord
  has_many :posts
end

# Controller
class UsersController < ApplicationController
  def index
    @users = User.includes(:posts).all
  end
end

3. Service Objects

Service objects are used to encapsulate business logic into reusable units. They can be used to perform complex tasks, such as sending an email, processing a payment, or generating a report.

Service objects make the code more readable, maintainable, and testable. They also help to separate the concerns of the application.

Example Code:

# Service
class SendEmailService
  def initialize(user)
    @user = user
  end

  def call
    # Send an email to the user.
  end
end

# Controller
class UsersController < ApplicationController
  def index
    @users = User.all
  end

  def create
    user = User.new(user_params)
    if user.save
      SendEmailService.new(user).call
      redirect_to users_path
    else
      render :new
    end
  end

  private

  def user_params
    params.require(:user).permit(:name, :email)
  end
end

4. View Objects (Presenters)

View objects, also known as presenters, are used to prepare data for the view. They can be used to format the data, filter it, or add additional information.

View objects make the views more readable and maintainable. They also help to separate the concerns of the application.

Example Code:

# Presenter
class UserPresenter
  def initialize(user)
    @user = user
  end

  def name
    @user.name
  end

  def email
    @user.email
  end

  def created_at
    @user.created_at.strftime('%d %b %Y')
  end
end

# Controller
class UsersController < ApplicationController
  def index
    @users = User.all
    @users_presenters = @users.map { |user| UserPresenter.new(user) }
  end
end

5. Query Objects

Query objects are used to encapsulate query logic into reusable units. They can be used to perform complex queries without polluting the controller or model code.

Query objects make the code more readable, maintainable, and testable. They also help to separate the concerns of the application.

# Query
class RecentUsersQuery
  def call
    User.where(created_at: 1.week.ago..).order(created_at: :desc)
  end
end

# Controller
class UsersController < ApplicationController
  def index
    @users = RecentUsersQuery.new.call
  end
end

6. Decorators

Decorators are used to add new functionality or behavior to existing objects. They can be used to decorate models, views, or controllers.

Decorators make the code more modular and reusable. They also help to avoid cluttering the original objects with additional code.

Example Code:

# Decorator
class UserDecorator
  def initialize(user)
    @user = user
  end

  def name
    @user.name
  end

  def email
    @user.email
  end

  def created_at
    @user.created_at.strftime('%d %b %Y')
  end

  def gravatar_url
    "https://www.gravatar.com/avatar/#{@user.email_digest}"
  end
end

# Controller
class UsersController < ApplicationController
  def index
    @users = User.all
    @users_decorators = @users.map { |user| UserDecorator.new(user) }
  end
end

7. Concerns

Concerns are used to group related code together. They can be used to encapsulate functionality that is shared across multiple models, views, or controllers.

Concerns make the code more modular and reusable. They also help to improve the readability and maintainability of the code.

Example Code:

# Concern
module Validatable
  def validates(*args)
    super
    validate(*args)
  end

  def validate(*args)
    # Validation logic.
  end
end

# Model
class User < ApplicationRecord
  include Validatable
  validates :name, presence: true
  validates :email, presence: true, uniqueness: true
end

8. Callbacks

Callbacks are used to execute code before or after a specific event. They can be used to perform tasks such as validation, logging, or caching.

Callbacks make the code more modular and reusable. They also help to avoid cluttering the models with additional code.

Example Code:

# Model
class User < ApplicationRecord
  before_validation :strip_whitespace

  private

  def strip_whitespace
    self.name.strip!
    self.email.strip!
  end
end

9. Scopes

Scopes are used to define named queries. They can be used to filter, sort, or order the results of a query.

Scopes make the code more readable and maintainable. They also help to avoid repeating the same query logic in multiple places.

Example Code:

# Model
class User < ApplicationRecord
  scope :active, -> { where(active: true) }
  scope :recent, -> { order(created_at: :desc) }
end

# Controller
class UsersController < ApplicationController
  def index
    @users = User.active.recent.all
  end
end

10. Namespaces

Namespaces are used to group related classes and modules together. They help to organize the code and avoid name collisions.

Namespaces make the code more modular and reusable. They also help to improve the readability and maintainability of the code.

Example Code:

# Controller
module Admin
  class UsersController < ApplicationController
    def index
      @users = User.all
    end
  end
end

These are just a few of the many Ruby on Rails design patterns that can be used to write faster and more efficient code. By using these patterns, you can improve the quality and maintainability of your Rails applications.

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