first commit

app/controllers/application_controller.rb

@@ -0,0 +1,9 @@
+class ApplicationController < ActionController::API
+  rescue_from ActiveRecord::RecordNotFound, with: :render_not_found
+
+  private
+
+  def render_not_found
+    render json: { error: "not_found" }, status: :not_found
+  end
+end

app/controllers/health_controller.rb

@@ -0,0 +1,8 @@
+class HealthController < ActionController::API
+  def show
+    ActiveRecord::Base.connection.select_value("SELECT 1")
+    head :ok
+  rescue ActiveRecord::ActiveRecordError
+    head :service_unavailable
+  end
+end

app/controllers/todos_controller.rb

@@ -0,0 +1,41 @@
+class TodosController < ApplicationController
+  before_action :set_todo, only: %i[show update destroy]
+
+  def index
+    render json: Todo.order(created_at: :desc)
+  end
+
+  def show
+    render json: @todo
+  end
+
+  def create
+    todo = Todo.new(todo_params)
+    todo.save!
+    render json: todo, status: :created
+  rescue ActiveRecord::RecordInvalid => error
+    render json: { errors: error.record.errors }, status: :unprocessable_entity
+  end
+
+  def update
+    @todo.update!(todo_params)
+    render json: @todo
+  rescue ActiveRecord::RecordInvalid => error
+    render json: { errors: error.record.errors }, status: :unprocessable_entity
+  end
+
+  def destroy
+    @todo.destroy!
+    head :no_content
+  end
+
+  private
+
+  def set_todo
+    @todo = Todo.find(params[:id])
+  end
+
+  def todo_params
+    params.expect(todo: %i[title completed])
+  end
+end

app/models/application_record.rb

@@ -0,0 +1,3 @@
+class ApplicationRecord < ActiveRecord::Base
+  primary_abstract_class
+end

app/models/todo.rb

@@ -0,0 +1,3 @@
+class Todo < ApplicationRecord
+  validates :title, presence: true, length: { maximum: 255 }
+end