Merge pull request #182 from orgsync/interface-filter

Add interface filter

CHANGELOG.md

@@ -1,5 +1,6 @@
 # [Master][]
 
+- Add an interface filter.
 - Add missing translation for symbol filters.
 
 # [1.2.1][] (2014-05-02)

benchmarks/filters.rb

@@ -26,6 +26,7 @@
   float:     [0.0, '0.0', 0],
   hash:      [Hash.new], # TODO
   integer:   [0, '0', 0.0],
+  interface: [Object.new],
   model:     [Object.new], # TODO: Reconstantizing.
   string:    [''], # TODO: Without strip.
   symbol:    [:'', ''],

lib/active_interaction.rb

@@ -30,6 +30,7 @@
 require 'active_interaction/filters/float_filter'
 require 'active_interaction/filters/hash_filter'
 require 'active_interaction/filters/integer_filter'
+require 'active_interaction/filters/interface_filter'
 require 'active_interaction/filters/model_filter'
 require 'active_interaction/filters/string_filter'
 require 'active_interaction/filters/symbol_filter'

lib/active_interaction/filters/interface_filter.rb

@@ -0,0 +1,42 @@
+# coding: utf-8
+
+module ActiveInteraction
+  class Base
+    # @!method self.interface(*attributes, options = {})
+    #   Creates accessors for the attributes and ensures that values passed to
+    #   the attributes implement an interface.
+    #
+    #   @!macro filter_method_params
+    #   @option options [Array<Symbol>] :methods ([]) the methods that objects
+    #     conforming to this interface should respond to
+    #
+    #   @example
+    #     interface :anything
+    #   @example
+    #     interface :serializer,
+    #       methods: [:dump, :load]
+  end
+
+  # @private
+  class InterfaceFilter < Filter
+    def cast(value)
+      matches?(value) ? value : super
+    end
+
+    private
+
+    # @param object [Object]
+    #
+    # @return [Boolean]
+    def matches?(object)
+      methods.all? { |method| object.respond_to?(method) }
+    rescue NoMethodError
+      false
+    end
+
+    # @return [Array<Symbol>]
+    def methods
+      options.fetch(:methods, [])
+    end
+  end
+end

lib/active_interaction/locale/en.yml

@@ -16,6 +16,7 @@ en:
       float: float
       hash: hash
       integer: integer
+      interface: interface
       model: model
       string: string
       symbol: symbol

spec/active_interaction/filters/interface_filter_spec.rb

@@ -0,0 +1,46 @@
+# coding: utf-8
+
+require 'spec_helper'
+require 'json'
+require 'yaml'
+
+describe ActiveInteraction::InterfaceFilter, :filter do
+  include_context 'filters'
+  it_behaves_like 'a filter'
+
+  before { options[:methods] = [:dump, :load] }
+
+  describe '#cast' do
+    let(:result) { filter.cast(value) }
+
+    context 'with an Object' do
+      let(:value) { Object.new }
+
+      it 'raises an error' do
+        expect { result }.to raise_error ActiveInteraction::InvalidValueError
+      end
+    end
+
+    context 'with JSON' do
+      let(:value) { JSON }
+
+      it 'returns an Array' do
+        expect(result).to eql value
+      end
+    end
+
+    context 'with YAML' do
+      let(:value) { YAML }
+
+      it 'returns an Hash' do
+        expect(result).to eql value
+      end
+    end
+  end
+
+  describe '#database_column_type' do
+    it 'returns :string' do
+      expect(filter.database_column_type).to eql :string
+    end
+  end
+end

spec/active_interaction/integration/interface_interaction_spec.rb

@@ -0,0 +1,12 @@
+# coding: utf-8
+
+require 'spec_helper'
+require 'json'
+require 'yaml'
+
+describe 'InterfaceInteraction' do
+  it_behaves_like 'an interaction',
+    :interface,
+    -> { [JSON, YAML].sample },
+    methods: [:dump, :load]
+end