Generate api controller if Rails API option is enabled

lib/generators/rails/templates/api_controller.rb

@@ -0,0 +1,63 @@
+<% if namespaced? -%>
+require_dependency "<%= namespaced_file_path %>/application_controller"
+
+<% end -%>
+<% module_namespacing do -%>
+class <%= controller_class_name %>Controller < ApplicationController
+  before_action :set_<%= singular_table_name %>, only: [:show, :update, :destroy]
+
+  # GET <%= route_url %>
+  # GET <%= route_url %>.json
+  def index
+    @<%= plural_table_name %> = <%= orm_class.all(class_name) %>
+  end
+
+  # GET <%= route_url %>/1
+  # GET <%= route_url %>/1.json
+  def show
+  end
+
+  # POST <%= route_url %>
+  # POST <%= route_url %>.json
+  def create
+    @<%= singular_table_name %> = <%= orm_class.build(class_name, "#{singular_table_name}_params") %>
+
+    if @<%= orm_instance.save %>
+      render :show, status: :created, location: <%= "@#{singular_table_name}" %>
+    else
+      render json: <%= "@#{orm_instance.errors}" %>, status: :unprocessable_entity
+    end
+  end
+
+  # PATCH/PUT <%= route_url %>/1
+  # PATCH/PUT <%= route_url %>/1.json
+  def update
+    if @<%= orm_instance.update("#{singular_table_name}_params") %>
+      render :show, status: :ok, location: <%= "@#{singular_table_name}" %>
+    else
+      render json: <%= "@#{orm_instance.errors}" %>, status: :unprocessable_entity
+    end
+  end
+
+  # DELETE <%= route_url %>/1
+  # DELETE <%= route_url %>/1.json
+  def destroy
+    @<%= orm_instance.destroy %>
+  end
+
+  private
+    # Use callbacks to share common setup or constraints between actions.
+    def set_<%= singular_table_name %>
+      @<%= singular_table_name %> = <%= orm_class.find(class_name, "params[:id]") %>
+    end
+
+    # Never trust parameters from the scary internet, only allow the white list through.
+    def <%= "#{singular_table_name}_params" %>
+      <%- if attributes_names.empty? -%>
+      params[<%= ":#{singular_table_name}" %>]
+      <%- else -%>
+      params.require(<%= ":#{singular_table_name}" %>).permit(<%= attributes_names.map { |name| ":#{name}" }.join(', ') %>)
+      <%- end -%>
+    end
+end
+<% end -%>

lib/jbuilder/railtie.rb

@@ -13,6 +13,7 @@ class Railtie < ::Rails::Railtie
         ActiveSupport.on_load :action_controller do
           include ActionView::Rendering
           include ActionController::Helpers
+          include ActionController::ImplicitRender
         end
       end
     end

test/scaffold_api_controller_generator_test.rb

@@ -0,0 +1,46 @@
+require 'test_helper'
+require 'rails/generators/test_case'
+require 'generators/rails/scaffold_controller_generator'
+
+if Rails::VERSION::MAJOR > 4
+
+  class ScaffoldApiControllerGeneratorTest < Rails::Generators::TestCase
+    tests Rails::Generators::ScaffoldControllerGenerator
+    arguments %w(Post title body:text --api)
+    destination File.expand_path('../tmp', __FILE__)
+    setup :prepare_destination
+
+    test 'controller content' do
+      run_generator
+
+      assert_file 'app/controllers/posts_controller.rb' do |content|
+        assert_instance_method :index, content do |m|
+          assert_match /@posts = Post\.all/, m
+        end
+
+        assert_instance_method :show, content do |m|
+          assert m.blank?
+        end
+
+        assert_instance_method :create, content do |m|
+          assert_match /@post = Post\.new\(post_params\)/, m
+          assert_match /@post\.save/, m
+          assert_match /render :show, status: :created, location: @post/, m
+          assert_match /render json: @post\.errors, status: :unprocessable_entity/, m
+        end
+
+        assert_instance_method :update, content do |m|
+          assert_match /render :show, status: :ok, location: @post/, m
+          assert_match /render json: @post.errors, status: :unprocessable_entity/, m
+        end
+
+        assert_instance_method :destroy, content do |m|
+          assert_match /@post\.destroy/, m
+        end
+
+        assert_match(/def post_params/, content)
+        assert_match(/params\.require\(:post\)\.permit\(:title, :body\)/, content)
+      end
+    end
+  end
+end