implement schemable

lib/json_api_client/helpers/schemable.rb

@@ -3,16 +3,58 @@ module Helpers
     module Schemable
       extend ActiveSupport::Concern
 
-      Field = Struct.new(:name, :type, :default)
+      Field = Struct.new(:name, :type, :default) do
+        def cast(value)
+          return nil if value.nil?
+
+          case type
+          when :integer
+            value.to_i
+          when :string
+            value.to_s
+          when :float
+            value.to_f
+          when :boolean
+            !!value
+          end
+        end
+      end
 
       included do
-        class_attribute :schema
-        self.schema = []
+        initializer do |obj, params|
+          obj.send(:set_default_values)
+        end
+      end
+
+      class Schema
+        def initialize
+          @fields = {}
+        end
+
+        def add(field)
+          @fields[field.name.to_sym] = field
+        end
+
+        def size
+          @fields.size
+        end
+
+        def each_property(&block)
+          @fields.values.each(&block)
+        end
+
+        def [](property_name)
+          @fields[property_name.to_sym]
+        end
       end
 
       module ClassMethods
-        def property(name, options = {})
+        def schema
+          @schema ||= Schema.new
+        end
 
+        def property(name, options = {})
+          schema.add(Field.new(name, options[:type], options[:default]))
         end
 
         def properties(*names)
@@ -22,6 +64,29 @@ def properties(*names)
           end
         end
       end
+
+      protected
+
+      def set_attribute(name, value)
+        property = property_for(name)
+        value = property.cast(value) if property
+        super(name, value)
+      end
+
+      def has_attribute?(attr_name)
+        !!self.class.schema[attr_name] || super
+      end
+
+      def set_default_values
+        self.class.schema.each_property do |property|
+          attributes[property.name] = property.default unless attributes.has_key?(property.name)
+        end
+      end
+
+      def property_for(name)
+        self.class.schema[name]
+      end
+
     end
   end
 end

test/unit/schemable_test.rb

@@ -21,8 +21,8 @@ def test_defines_fields
     resource = SchemaResource.new
 
     %w(a b c d).each do |method_name|
-      assert resource.respond_to?(method_name)
-      assert resource.respond_to?("#{method_name}=")
+      assert resource.respond_to?(method_name), "should respond_to?(:#{method_name})"
+      assert resource.respond_to?("#{method_name}="), "should respond_to?(:#{method_name}=)"
     end
 
     assert_equal 4, SchemaResource.schema.size