Implement ArraySerializer and move old serialization API to a new namespace.

The following constants were renamed:

  ActiveModel::Serialization     => ActiveModel::Serializable
  ActiveModel::Serializers::JSON => ActiveModel::Serializable::JSON
  ActiveModel::Serializers::Xml  => ActiveModel::Serializable::XML

The main motivation for such a change is that `ActiveModel::Serializers::JSON`
was not actually a serializer, but a module that when included allows the target to be serializable to JSON.

With such changes, we were able to clean up the namespace to add true serializers as the ArraySerializer.

2 files changed, 303 insertions, 0 deletions

diff --git a/activemodel/lib/active_model/serializable/json.rb b/activemodel/lib/active_model/serializable/json.rb
new file mode 100644
index 0000000000..79173929e4
--- /dev/null
+++ b/activemodel/lib/active_model/serializable/json.rb
@@ -0,0 +1,108 @@
+require 'active_support/json'
+require 'active_support/core_ext/class/attribute'
+
+module ActiveModel
+  # == Active Model Serializable as JSON
+  module Serializable
+    module JSON
+      extend ActiveSupport::Concern
+      include ActiveModel::Serializable
+
+      included do
+        extend ActiveModel::Naming
+
+        class_attribute :include_root_in_json
+        self.include_root_in_json = true
+      end
+
+      # Returns a hash representing the model. Some configuration can be
+      # passed through +options+.
+      #
+      # The option <tt>include_root_in_json</tt> controls the top-level behavior
+      # of +as_json+. If true (the default) +as_json+ will emit a single root
+      # node named after the object's type. For example:
+      #
+      #   user = User.find(1)
+      #   user.as_json
+      #   # => { "user": {"id": 1, "name": "Konata Izumi", "age": 16,
+      #                   "created_at": "2006/08/01", "awesome": true} }
+      #
+      #   ActiveRecord::Base.include_root_in_json = false
+      #   user.as_json
+      #   # => {"id": 1, "name": "Konata Izumi", "age": 16,
+      #         "created_at": "2006/08/01", "awesome": true}
+      #
+      # This behavior can also be achieved by setting the <tt>:root</tt> option to +false+ as in:
+      #
+      #   user = User.find(1)
+      #   user.as_json(root: false)
+      #   # =>  {"id": 1, "name": "Konata Izumi", "age": 16,
+      #          "created_at": "2006/08/01", "awesome": true}
+      #
+      # The remainder of the examples in this section assume include_root_in_json is set to
+      # <tt>false</tt>.
+      #
+      # Without any +options+, the returned Hash will include all the model's
+      # attributes. For example:
+      #
+      #   user = User.find(1)
+      #   user.as_json
+      #   # => {"id": 1, "name": "Konata Izumi", "age": 16,
+      #         "created_at": "2006/08/01", "awesome": true}
+      #
+      # The <tt>:only</tt> and <tt>:except</tt> options can be used to limit the attributes
+      # included, and work similar to the +attributes+ method. For example:
+      #
+      #   user.as_json(:only => [ :id, :name ])
+      #   # => {"id": 1, "name": "Konata Izumi"}
+      #
+      #   user.as_json(:except => [ :id, :created_at, :age ])
+      #   # => {"name": "Konata Izumi", "awesome": true}
+      #
+      # To include the result of some method calls on the model use <tt>:methods</tt>:
+      #
+      #   user.as_json(:methods => :permalink)
+      #   # => {"id": 1, "name": "Konata Izumi", "age": 16,
+      #         "created_at": "2006/08/01", "awesome": true,
+      #         "permalink": "1-konata-izumi"}
+      #
+      # To include associations use <tt>:include</tt>:
+      #
+      #   user.as_json(:include => :posts)
+      #   # => {"id": 1, "name": "Konata Izumi", "age": 16,
+      #         "created_at": "2006/08/01", "awesome": true,
+      #         "posts": [{"id": 1, "author_id": 1, "title": "Welcome to the weblog"},
+      #                   {"id": 2, author_id: 1, "title": "So I was thinking"}]}
+      #
+      # Second level and higher order associations work as well:
+      #
+      #   user.as_json(:include => { :posts => {
+      #                                  :include => { :comments => {
+      #                                                :only => :body } },
+      #                                  :only => :title } })
+      #   # => {"id": 1, "name": "Konata Izumi", "age": 16,
+      #         "created_at": "2006/08/01", "awesome": true,
+      #         "posts": [{"comments": [{"body": "1st post!"}, {"body": "Second!"}],
+      #                    "title": "Welcome to the weblog"},
+      #                   {"comments": [{"body": "Don't think too hard"}],
+      #                    "title": "So I was thinking"}]}
+      def as_json(options = nil)
+        root = include_root_in_json
+        root = options[:root] if options.try(:key?, :root)
+        if root
+          root = self.class.model_name.element if root == true
+          { root => serializable_hash(options) }
+        else
+          serializable_hash(options)
+        end
+      end
+
+      def from_json(json, include_root=include_root_in_json)
+        hash = ActiveSupport::JSON.decode(json)
+        hash = hash.values.first if include_root
+        self.attributes = hash
+        self
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/serializable/xml.rb b/activemodel/lib/active_model/serializable/xml.rb
new file mode 100644
index 0000000000..d11cee9b42
--- /dev/null
+++ b/activemodel/lib/active_model/serializable/xml.rb
@@ -0,0 +1,195 @@
+require 'active_support/core_ext/array/wrap'
+require 'active_support/core_ext/class/attribute_accessors'
+require 'active_support/core_ext/array/conversions'
+require 'active_support/core_ext/hash/conversions'
+require 'active_support/core_ext/hash/slice'
+
+module ActiveModel
+  # == Active Model Serializable as XML
+  module Serializable
+    module XML
+      extend ActiveSupport::Concern
+      include ActiveModel::Serializable
+
+      class Serializer #:nodoc:
+        class Attribute #:nodoc:
+          attr_reader :name, :value, :type
+
+          def initialize(name, serializable, value)
+            @name, @serializable = name, serializable
+            value  = value.in_time_zone if value.respond_to?(:in_time_zone)
+            @value = value
+            @type  = compute_type
+          end
+
+          def decorations
+            decorations = {}
+            decorations[:encoding] = 'base64' if type == :binary
+            decorations[:type] = (type == :string) ? nil : type
+            decorations[:nil] = true if value.nil?
+            decorations
+          end
+
+        protected
+
+          def compute_type
+            return if value.nil?
+            type = ActiveSupport::XmlMini::TYPE_NAMES[value.class.name]
+            type ||= :string if value.respond_to?(:to_str)
+            type ||= :yaml
+            type
+          end
+        end
+
+        class MethodAttribute < Attribute #:nodoc:
+        end
+
+        attr_reader :options
+
+        def initialize(serializable, options = nil)
+          @serializable = serializable
+          @options = options ? options.dup : {}
+        end
+
+        def serializable_hash
+          @serializable.serializable_hash(@options.except(:include))
+        end
+
+        def serializable_collection
+          methods = Array.wrap(options[:methods]).map(&:to_s)
+          serializable_hash.map do |name, value|
+            name = name.to_s
+            if methods.include?(name)
+              self.class::MethodAttribute.new(name, @serializable, value)
+            else
+              self.class::Attribute.new(name, @serializable, value)
+            end
+          end
+        end
+
+        def serialize
+          require 'builder' unless defined? ::Builder
+
+          options[:indent]  ||= 2
+          options[:builder] ||= ::Builder::XmlMarkup.new(:indent => options[:indent])
+
+          @builder = options[:builder]
+          @builder.instruct! unless options[:skip_instruct]
+
+          root = (options[:root] || @serializable.class.model_name.element).to_s
+          root = ActiveSupport::XmlMini.rename_key(root, options)
+
+          args = [root]
+          args << {:xmlns => options[:namespace]} if options[:namespace]
+          args << {:type => options[:type]} if options[:type] && !options[:skip_types]
+
+          @builder.tag!(*args) do
+            add_attributes_and_methods
+            add_includes
+            add_extra_behavior
+            add_procs
+            yield @builder if block_given?
+          end
+        end
+
+      private
+
+        def add_extra_behavior
+        end
+
+        def add_attributes_and_methods
+          serializable_collection.each do |attribute|
+            key = ActiveSupport::XmlMini.rename_key(attribute.name, options)
+            ActiveSupport::XmlMini.to_tag(key, attribute.value,
+              options.merge(attribute.decorations))
+          end
+        end
+
+        def add_includes
+          @serializable.send(:serializable_add_includes, options) do |association, records, opts|
+            add_associations(association, records, opts)
+          end
+        end
+
+        # TODO This can likely be cleaned up to simple use ActiveSupport::XmlMini.to_tag as well.
+        def add_associations(association, records, opts)
+          merged_options = opts.merge(options.slice(:builder, :indent))
+          merged_options[:skip_instruct] = true
+
+          if records.is_a?(Enumerable)
+            tag  = ActiveSupport::XmlMini.rename_key(association.to_s, options)
+            type = options[:skip_types] ? { } : {:type => "array"}
+            association_name = association.to_s.singularize
+            merged_options[:root] = association_name
+
+            if records.empty?
+              @builder.tag!(tag, type)
+            else
+              @builder.tag!(tag, type) do
+                records.each do |record|
+                  if options[:skip_types]
+                    record_type = {}
+                  else
+                    record_class = (record.class.to_s.underscore == association_name) ? nil : record.class.name
+                    record_type = {:type => record_class}
+                  end
+
+                  record.to_xml merged_options.merge(record_type)
+                end
+              end
+            end
+          else
+            merged_options[:root] = association.to_s
+            records.to_xml(merged_options)
+          end
+        end
+
+        def add_procs
+          if procs = options.delete(:procs)
+            Array.wrap(procs).each do |proc|
+              if proc.arity == 1
+                proc.call(options)
+              else
+                proc.call(options, @serializable)
+              end
+            end
+          end
+        end
+      end
+
+      # Returns XML representing the model. Configuration can be
+      # passed through +options+.
+      #
+      # Without any +options+, the returned XML string will include all the model's
+      # attributes. For example:
+      #
+      #   user = User.find(1)
+      #   user.to_xml
+      #
+      #   <?xml version="1.0" encoding="UTF-8"?>
+      #   <user>
+      #     <id type="integer">1</id>
+      #     <name>David</name>
+      #     <age type="integer">16</age>
+      #     <created-at type="datetime">2011-01-30T22:29:23Z</created-at>
+      #   </user>
+      #
+      # The <tt>:only</tt> and <tt>:except</tt> options can be used to limit the attributes
+      # included, and work similar to the +attributes+ method.
+      #
+      # To include the result of some method calls on the model use <tt>:methods</tt>.
+      #
+      # To include associations use <tt>:include</tt>.
+      #
+      # For further documentation see activerecord/lib/active_record/serializers/xml_serializer.xml.
+      def to_xml(options = {}, &block)
+        Serializer.new(self, options).serialize(&block)
+      end
+
+      def from_xml(xml)
+        self.attributes = Hash.from_xml(xml).values.first
+        self
+      end
+    end
+  end
+end