API for coupons

app/controllers/api/coupons_controller.rb

@@ -0,0 +1,45 @@
+class API::CouponsController < API::ApiController
+  before_action :authenticate_user!
+  before_action :set_coupon, only: [:show, :update, :destroy]
+
+  def index
+    @coupons = Coupon.all
+  end
+
+  def show
+  end
+
+  def create
+    authorize Coupon
+    @coupon = Coupon.new(coupon_params)
+    if @coupon.save
+      render :show, status: :created, location: @coupon
+    else
+      render json: @coupon.errors, status: :unprocessable_entity
+    end
+  end
+
+  def update
+    authorize Coupon
+    if @coupon.update(coupon_params)
+      render :show, status: :ok, location: @coupon
+    else
+      render json: @coupon.errors, status: :unprocessable_entity
+    end
+  end
+
+  def destroy
+    authorize Coupon
+    @coupon.destroy
+    head :no_content
+  end
+
+  private
+  def set_coupon
+    @coupon = Coupon.find(params[:id])
+  end
+
+  def coupon_params
+    params.require(:coupon).permit(:name, :code, :percent_off, :valid_until, :max_usages, :active)
+  end
+end

app/policies/coupon_policy.rb

@@ -0,0 +1,7 @@
+class CouponPolicy < ApplicationPolicy
+  %w(index show create update destroy).each do |action|
+    define_method "#{action}?" do
+      user.is_admin?
+    end
+  end
+end

app/views/api/coupons/_coupon.json.jbuilder

@@ -0,0 +1 @@
+json.extract! coupon, :id, :name, :code, :percent_off, :valid_until, :max_usages, :active, :created_at

app/views/api/coupons/show.json.jbuilder

@@ -0,0 +1 @@
+json.partial! 'api/coupons/coupon', coupon: @coupon