Implement Decoration mixin

lib/pragma/operation.rb

@@ -5,6 +5,7 @@
 require 'pragma/operation/base'
 require 'pragma/operation/authorization'
 require 'pragma/operation/validation'
+require 'pragma/operation/decoration'
 
 module Pragma
   # Operations provide business logic encapsulation for your JSON API.

lib/pragma/operation/base.rb

@@ -72,6 +72,7 @@ def inherited(child)
           child.class_eval do
             include Authorization
             include Validation
+            include Decoration
 
             before :setup_context
             around :handle_halt

lib/pragma/operation/decoration.rb

@@ -0,0 +1,52 @@
+module Pragma
+  module Operation
+    # Provides integration with {https://github.com/pragmarb/pragma-decorator Pragma::Decorator}.
+    #
+    # @author Alessandro Desantis
+    module Decoration
+      def self.included(base)
+        base.extend ClassMethods
+        base.include InstanceMethods
+      end
+
+      module ClassMethods # :nodoc:
+        # Sets the decorator to use for validating this operation.
+        #
+        # @param klass [Class] a subclass of +Pragma::Decorator::Base+
+        def decorator(klass)
+          @decorator = klass
+        end
+
+        # Builds the decorator for the given resource, using the previously defined decorator class.
+        #
+        # Works with both singular resources and collections.
+        #
+        # @param resource [Object]
+        #
+        # @return [Pragma::Decorator::Base]
+        #
+        # @see #decorator
+        def decorate(resource)
+          @decorator.represent(resource)
+        end
+      end
+
+      module InstanceMethods # :nodoc:
+        # Builds the decorator for the given resource, using the previously defined decorator class.
+        #
+        # This is just an instance-level alias of {.decorate}. You should use this from
+        # inside the operation.
+        #
+        # @param resource [Object]
+        #
+        # @return [Pragma::Decorator::Base]
+        #
+        # @see .decorator
+        # @see .decorate
+        def decorate(resource)
+          self.class.decorate(resource)
+        end
+      end
+    end
+  end
+end

pragma-operation.gemspec

@@ -24,6 +24,7 @@ Gem::Specification.new do |spec|
 
   spec.add_development_dependency 'pragma-policy', '~> 0.1.0'
   spec.add_development_dependency 'pragma-contract', '~> 0.1.0'
+  spec.add_development_dependency 'pragma-decorator', '~> 0.1.0'
 
   spec.add_development_dependency "bundler"
   spec.add_development_dependency "rake"

spec/pragma/operation/decoration_spec.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+require 'pragma/decorator'
+
+RSpec.describe Pragma::Operation::Authorization do
+  let(:context) { operation.call }
+
+  let(:decorator_klass) do
+    Class.new(Pragma::Decorator::Base) do
+      property :title
+    end
+  end
+
+  describe '#decorate' do
+    let(:operation) do
+      Class.new(Pragma::Operation::Base) do
+        def call
+          respond_with status: :ok, resource: decorate(OpenStruct.new(
+            title: 'Test',
+            foo: 'bar'
+          )).to_hash
+        end
+      end.tap do |klass|
+        klass.send(:decorator, decorator_klass)
+      end
+    end
+
+    it 'decorates the resource' do
+      expect(context.resource).to eq('title' => 'Test')
+    end
+  end
+end