Patternist

Patternist is a Ruby gem that provides reusable utilities and patterns for Ruby and Rails applications. It offers a collection of modules designed to reduce boilerplate code and standardize and protect common patterns.

• Controller Helpers: Automatic resource inference and naming conventions
• RESTful Actions: Complete CRUD operations with minimal configuration
• Response Handling: Unified response formatting for HTML and JSON
• Rails Integration: Seamless integration with Rails applications
• Error Handling: Comprehensive error handling with custom exceptions

Add this line to your application's Gemfile:

gem 'patternist'

And then execute:

bundle install

Or install it yourself as:

gem install patternist

The Patternist::Controller module provides complete CRUD operations:

class PostsController < ApplicationController
  include Patternist::Controller

  private

  def resource_params
    params.require(:post).permit(:title, :body)
  end
end

This automatically provides all standard RESTful actions:

• index - Lists all resources
• show - Shows a single resource
• new - Prepares a new resource
• create - Creates a new resource
• edit - Prepares a resource for editing
• update - Updates an existing resource
• destroy - Destroys a resource

The Patternist::Controllers::ActionPack::Helpers module provides automatic resource inference and helper methods for controllers:

class PostsController < ApplicationController
  include Patternist::Controllers::ActionPack::Helpers

  def index
    # Automatically infers @posts from controller name
    set_collection_instance(Post.all)
  end

  def show
    # Automatically infers @post from controller name
    set_resource_instance(Post.find(params[:id]))
  end
end

The helpers module provides several useful methods:

• resource_class - Inferred model class (e.g., Post for PostsController)
• resource_name - Underscored resource name (e.g., "post")
• resource_class_name - Human-readable resource name (e.g., "Post")
• collection_name - Pluralized resource name (e.g., "posts")
• instance_variable_name - Instance variable name for a resource
• resource - Get the resource instance variable
• id_param - Get the ID parameter from params

The Patternist::Controllers::ActionPack::ResponseHandling module provides unified response formatting:

class PostsController < ApplicationController
  include Patternist::Controllers::ActionPack::ResponseHandling

  def create
    @post = Post.new(post_params)

    format_response(@post,
                    notice: "Post created successfully",
                    status: :created,
                    on_error_render: :new) do
      @post.save
    end
  end
end

You can customize response handling with custom format handlers:

format_response(@post,
                notice: "Success",
                status: :ok,
                on_error_render: :edit,
                formats: {
                  html: -> { redirect_to custom_path },
                  json: -> { render json: custom_serializer(@post) },
                  on_error_html: -> { render :custom_error },
                  on_error_json: -> { render json: { error: "Custom error" } }
                }) do
  @post.update(post_params)
end

Provides helper methods for resource handling and naming conventions.

Class Methods:

• resource_class - Returns the inferred resource class
• resource_name - Returns the underscored resource name

Instance Methods:

• resource_class - Returns the resource class
• resource_name - Returns the resource name
• resource_class_name - Returns the human-readable resource name
• collection_name - Returns the pluralized resource name
• instance_variable_name(name) - Returns instance variable name
• resource - Returns the resource instance
• id_param - Returns the ID parameter
• set_collection_instance(value) - Sets the collection instance variable
• set_resource_instance(value) - Sets the resource instance variable

Provides standard RESTful actions for controllers.

Actions:

• index - Lists all resources
• show - Shows a single resource
• new - Prepares a new resource
• create - Creates a new resource
• edit - Prepares a resource for editing
• update - Updates an existing resource
• destroy - Destroys a resource

Required Methods:

• resource_params - Must be implemented to define permitted parameters

Provides unified response formatting for different formats.

Methods:

• format_response(resource, notice:, status:, on_error_render:, formats: {}, &block) - Handles response formatting

• Ruby >= 3.1.0
• ActionPack >= 4.0 (for Rails integration)

class PostsController < ApplicationController
  include Patternist::Controller

  # All RESTful actions are automatically provided

  private

  def resource_params
    params.require(:post).permit(:title, :body, :published)
  end

  # Optional: Override collection for custom scoping
  def collection
    current_user.posts.published.includes(:author)
  end
end

class Admin::PostsController < ApplicationController
  include Patternist::Controller

  # Automatically infers Post class from Admin::PostsController

  private

  def resource_params
    params.require(:post).permit(:title, :body, :featured)
  end
end

class Api::V1::PostsController < ApplicationController
  include Patternist::Controller

  def create
    set_resource_instance(resource_class.new(resource_params))

    format_response(resource,
                    notice: "Post created successfully",
                    status: :created,
                    on_error_render: :new,
                    formats: {
                      json: -> { render json: resource, serializer: PostSerializer },
                      error_json: -> { render json: { errors: resource.errors.full_messages } }
                    }) do
      resource.save
    end
  end

  private

  def resource_params
    params.require(:post).permit(:title, :body)
  end
end

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To release a new version, update the version number in version.rb, update the CHANGELOG.md, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Run the test suite with:

bundle exec rspec

The project follows standard Ruby conventions and uses RSpec for testing.

Bug reports and pull requests are welcome on GitHub at https://github.com/xavius-rb/patternist. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in the Patternist project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.