rails-controllers

name	rails-controllers
description	Controller patterns, service delegation, strong parameters, and HTTP conventions for this Rails codebase

Controller Naming

• Controllers use Plural PascalCase (e.g., FacilitiesController)
• File names match class names: facilities_controller.rb
• Located in app/controllers/ directory

Thin Controller Pattern

• Keep controllers thin, delegate logic to services
• Controllers should handle:
  • Request/response cycle
  • Parameter handling
  • Response formatting
  • Redirect/flow control

Service Delegation

def create
  result = FacilityCreateService.call(facility_params)

  if result.errors.any?
    render json: { errors: result.errors }, status: :unprocessable_content
  else
    render json: result.data, status: :created
  end
end

Before Actions

• Use before_action for shared logic:

  before_action :authenticate_user!
  before_action :set_facility, only: [:show, :update, :destroy]
  

Strong Parameters

def facility_params
  params.require(:facility).permit(:name, :address, :status)
end

def nested_params
  params.require(:facility).permit(:name, bookings_attributes: [:id, :date, :_destroy])
end

HTTP Status Codes

• Return appropriate HTTP status codes:
  • 200 OK - Successful GET/PUT/PATCH
  • 201 Created - Successful POST
  • 204 No Content - Successful DELETE
  • 400 Bad Request - Invalid request
  • 401 Unauthorized - Not authenticated
  • 403 Forbidden - Not authorized
  • 404 Not Found - Resource not found
  • 422 Unprocessable Content - Validation errors
  • 500 Internal Server Error - Server error

Response Formats

# JSON response
render json: @facility

# JSON with status
render json: @facility, status: :ok

# JSON with errors
render json: { errors: ["Validation failed"] }, status: :unprocessable_content

# Redirect
redirect_to @facility, notice: "Success"

# Render template
render :new

Testing Controllers

• Test files located in spec/controllers/
• Use *_controller_spec.rb suffix
• Test actions, status codes, and responses
• Use RSpec request specs for API endpoints

Example Controller

class FacilitiesController < ApplicationController
  before_action :authenticate_user!
  before_action :set_facility, only: [:show, :update, :destroy]

  def index
    @facilities = Facility.all
    render json: @facilities
  end

  def show
    render json: @facility
  end

  def create
    result = FacilityCreateService.call(facility_params)

    if result.errors.any?
      render json: { errors: result.errors }, status: :unprocessable_content
    else
      render json: result.data, status: :created
    end
  end

  private

  def set_facility
    @facility = Facility.find(params[:id])
  end

  def facility_params
    params.require(:facility).permit(:name, :address, :status)
  end
end

Important Notes

• Always use strong parameters
• Delegate business logic to services
• Return appropriate HTTP status codes
• Keep actions focused on request/response