Implement ignoring DSL to ignore attributes

README.md

@@ -143,6 +143,36 @@ end
 
 Although this might be useful sometimes, it's generally recommended to define a class for both Resource and Serializer.
 
+### Inheritance and Ignorance
+
+You can `exclude` or `ignore` certain attributes using `ignoring`.
+
+```ruby
+class Foo
+  attr_accessor :id, :name, :body
+
+  def initialize(id, name, body)
+    @id = id
+    @name = name
+    @body = body
+  end
+end
+
+class GenericFooResource
+  include Alba::Resource
+
+  attributes :id, :name, :body
+end
+
+class RestrictedFooResouce < GenericFooResource
+  ignoring :id, :body
+end
+
+RestrictedFooResouce.new(foo).serialize
+# => '{"name":"my foo"}'
+end
+```
+
 ## Comparison
 
 Alba is faster than alternatives.

lib/alba/resource.rb

@@ -114,6 +114,13 @@ def serializer(name)
       def key(key)
         @_key = key.to_sym
       end
+
+      # Use this DSL in child class to ignore certain attributes
+      def ignoring(*attributes)
+        attributes.each do |attr_name|
+          @_attributes.delete(attr_name)
+        end
+      end
     end
   end
 end

test/usecases/inheritance_and_ignorance_test.rb

@@ -0,0 +1,28 @@
+require_relative '../test_helper'
+
+class InheritanceAndIgnoranceTest < MiniTest::Test
+  class Foo
+    attr_accessor :id, :name, :body
+
+    def initialize(id, name, body)
+      @id = id
+      @name = name
+      @body = body
+    end
+  end
+
+  class GenericFooResource
+    include Alba::Resource
+
+    attributes :id, :name, :body
+  end
+
+  class RestrictedFooResouce < GenericFooResource
+    ignoring :id, :body
+  end
+
+  def test_it_ignores_attributes
+    foo = Foo.new(1, 'my foo', 'my body')
+    assert_equal '{"name":"my foo"}', RestrictedFooResouce.new(foo).serialize
+  end
+end