API Example

items_controller_a.rb

class ItemsController < ApplicationController
  def index
    @items = Item.all

    respond_to do |format|
      format.html { @items }
      format.json { render json: @items }
      format.xml  { render xml:  @items }
    end
  end

  def show
    @item = Item.find_by(id: params[:id])

    respond_to do |format|
      format.html { @item }
      format.json { render json: @item }
      format.xml  { render xml:  @item }
    end
  end
end

items_controller_b.rb

class ItemsController < ApplicationController
  respond_to :html, :json, :xml

  def index
    @items = Item.all

    respond_with @items
  end

  def show
    @item = Item.find_by(id: params[:id])

    respond_with @item
  end
end

items_controller_c.rb

class ItemsController < ApplicationController
  # More Code
  
  def create
    @item = Item.new(item_params)

    if @item.save
      respond_to do |format|
        format.html { redirect_to items_path, notice: "The item was created." }
        format.json { render json: @item }
        format.xml  { render xml:  @item }
      end
    else
      respond_to do |format|
        format.html do
          flash.now[:notice] = "The item was not created."
          render :new
        end

        format.json { render json: { messages: @item.errors.messages}, status: 400 }
        format.xml  { render xml:  { messages: @item.errors.messages}, status: 400 }
      end
    end
  end
  
  def update
    @item = Item.find(params[:id])

    if @item.update_attributes(item_params)
      respond_to do |format|
        format.html { redirect_to items_path, notice: "The item was updated." }
        format.json { render json: @item }
        format.xml  { render xml:  @item }
      end
    else
      respond_to do |format|
        format.html do
          flash.now[:notice] = "The item was not updated."
          render :edit
        end

        format.json { render json: { messages: @item.errors.messages}, status: 400 }
        format.xml  { render xml:  { messages: @item.errors.messages}, status: 400 }
      end
    end
  end
end

items_controller_d.rb

class Api::V1::ItemsController < ApplicationController
  respond_to :json, :xml

  def index
    respond_with Item.all
  end

  def show
    respond_with Item.find(params[:id])
  end

  def create
    respond_with Item.create(item_params)
  end

  def update
    respond_with Item.update(params[:id], item_params)
  end

  def delete
    respond_with Item.destroy(params[:id])
  end

  private

  def item_params
    params.require(:item).permit(:name, :description, :image_url)
  end
end