Add PORO serializable base class: ActiveModelSerializers::Model

Author: bf4

README.md

@@ -374,6 +374,13 @@ class PostSerializer < ActiveModel::Serializer
 end
 ```
 
+## Serializing non-ActiveRecord objects
+
+All serializable resources must pass the ActiveModel::Serializer::Lint::Tests.
+
+See the ActiveModelSerializers::Model for a base class that implements the full
+API for a plain-old Ruby object (PORO).
+
 ## Getting Help
 
 If you find a bug, please report an [Issue](https://github.com/rails-api/active_model_serializers/issues/new).

lib/active_model/serializer/lint.rb

@@ -80,8 +80,8 @@ def test_to_json
     # arguments (Rails 4.0) or a splat (Rails 4.1+).
     # Fails otherwise.
     #
-    # <tt>cache_key</tt> returns a (self-expiring) unique key for the object,
-    # which is used by the adapter.
+    # <tt>cache_key</tt> returns a (self-expiring) unique key for the object, and
+    # is part of the (self-expiring) cache_key, which is used by the adapter.
     # It is not required unless caching is enabled.
     def test_cache_key
       assert_respond_to resource, :cache_key
@@ -92,6 +92,19 @@ def test_cache_key
       assert_includes [-1, 0], actual_arity, "expected #{actual_arity.inspect} to be 0 or -1"
     end
 
+    # Passes if the object responds to <tt>updated_at</tt> and if it takes no
+    # arguments.
+    # Fails otherwise.
+    #
+    # <tt>updated_at</tt> returns a Time object or iso8601 string and
+    # is part of the (self-expiring) cache_key, which is used by the adapter.
+    # It is not required unless caching is enabled.
+    def test_updated_at
+      assert_respond_to resource, :updated_at
+      actual_arity = resource.method(:updated_at).arity
+      assert_equal actual_arity, 0, "expected #{actual_arity.inspect} to be 0"
+    end
+
     # Passes if the object responds to <tt>id</tt> and if it takes no
     # arguments.
     # Fails otherwise.

lib/active_model_serializers.rb

@@ -7,6 +7,9 @@ module ActiveModelSerializers
   mattr_accessor :logger
   self.logger = Rails.logger || Logger.new(IO::NULL)
 
+  extend ActiveSupport::Autoload
+  autoload :Model
+
   module_function
 
   # @note

lib/active_model_serializers/model.rb

@@ -0,0 +1,39 @@
+# ActiveModelSerializers::Model is a convenient
+# serializable class to inherit from when making
+# serializable non-activerecord objects.
+module ActiveModelSerializers
+  class Model
+    include ActiveModel::Model
+    include ActiveModel::Serializers::JSON
+
+    attr_reader :attributes
+
+    def initialize(attributes = {})
+      @attributes = attributes
+      super
+    end
+
+    # Defaults to the downcased model name.
+    def id
+      attributes.fetch(:id) { self.class.name.downcase }
+    end
+
+    # Defaults to the downcased model name and updated_at
+    def cache_key
+      attributes.fetch(:cache_key) { "#{self.class.name.downcase}/#{id}-#{updated_at.strftime("%Y%m%d%H%M%S%9N")}" }
+    end
+
+    # Defaults to the time the serializer file was modified.
+    def updated_at
+      attributes.fetch(:updated_at) { File.mtime(__FILE__) }
+    end
+
+    def read_attribute_for_serialization(key)
+      if key == :id || key == 'id'
+        attributes.fetch(key) { id }
+      else
+        attributes[key]
+      end
+    end
+  end
+end

test/action_controller/adapter_selector_test.rb

@@ -46,7 +46,7 @@ def test_render_using_adapter_override
 
       def test_render_skipping_adapter
         get :render_skipping_adapter
-        assert_equal '{"attributes":{"name":"Name 1","description":"Description 1","comments":"Comments 1"}}', response.body
+        assert_equal '{"name":"Name 1","description":"Description 1","comments":"Comments 1"}', response.body
       end
     end
   end

test/active_model_serializers/model_test.rb

@@ -0,0 +1,9 @@
+require 'test_helper'
+
+class ActiveModelSerializers::ModelTest < Minitest::Test
+  include ActiveModel::Serializer::Lint::Tests
+
+  def setup
+    @resource = ActiveModelSerializers::Model.new
+  end
+end

test/adapter/json/has_many_test.rb

@@ -36,7 +36,7 @@ def test_has_many_with_no_serializer
             assert_equal({
               id: 42,
               tags: [
-                { 'attributes' => { 'id' => 1, 'name' => '#hash_tag' } }
+                { 'id' => 1, 'name' => '#hash_tag' }
               ]
             }.to_json, adapter.serializable_hash[:post].to_json)
           end

test/fixtures/poro.rb

@@ -1,44 +1,16 @@
 verbose = $VERBOSE
 $VERBOSE = nil
-class Model
+class Model < ActiveModelSerializers::Model
   FILE_DIGEST = Digest::MD5.hexdigest(File.open(__FILE__).read)
 
-  def self.model_name
-    @_model_name ||= ActiveModel::Name.new(self)
-  end
-
-  def initialize(hash = {})
-    @attributes = hash
-  end
-
-  def cache_key
-    "#{self.class.name.downcase}/#{self.id}-#{self.updated_at.strftime("%Y%m%d%H%M%S%9N")}"
-  end
-
-  def serializable_hash(options = nil)
-    @attributes
-  end
-
-  def read_attribute_for_serialization(name)
-    if name == :id || name == 'id'
-      id
-    else
-      @attributes[name]
-    end
-  end
-
-  def id
-    @attributes[:id] || @attributes['id'] || object_id
-  end
-
   ### Helper methods, not required to be serializable
-  #
-  # Convenience for adding @attributes readers and writers
+
+  # Convenience when not adding @attributes readers and writers
   def method_missing(meth, *args)
     if meth.to_s =~ /^(.*)=$/
-      @attributes[$1.to_sym] = args[0]
-    elsif @attributes.key?(meth)
-      @attributes[meth]
+      attributes[$1.to_sym] = args[0]
+    elsif attributes.key?(meth)
+      attributes[meth]
     else
       super
     end
@@ -47,10 +19,6 @@ def method_missing(meth, *args)
   def cache_key_with_digest
     "#{cache_key}/#{FILE_DIGEST}"
   end
-
-  def updated_at
-    @attributes[:updated_at] ||= DateTime.now.to_time
-  end
 end
 
 class Profile < Model

test/lint_test.rb

@@ -24,6 +24,9 @@ def cache_key
         def id
         end
 
+        def updated_at
+        end
+
         def self.model_name
           @_model_name ||= ActiveModel::Name.new(self)
         end

test/serializers/associations_test.rb

@@ -54,7 +54,7 @@ def test_has_many_with_no_serializer
 
           assert_equal key, :tags
           assert_equal serializer, nil
-          assert_equal [{ attributes: { name: '#hashtagged' } }].to_json, options[:virtual_value].to_json
+          assert_equal [{ name: '#hashtagged' }].to_json, options[:virtual_value].to_json
         end
       end