Added ActiveRecord::Base#to_json/from_json (currently does not support :include like to_xml) [DHH]. Added ActiveRecord::Base#from_xml [DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7519 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

2 files changed, 345 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/serializers/json_serializer.rb b/activerecord/lib/active_record/serializers/json_serializer.rb
new file mode 100644
index 0000000000..97025ae4d3
--- /dev/null
+++ b/activerecord/lib/active_record/serializers/json_serializer.rb
@@ -0,0 +1,18 @@
+module ActiveRecord #:nodoc:
+  module Serialization
+    def to_json(options = {}, &block)
+      JsonSerializer.new(self, options).to_s
+    end
+
+    def from_json(json)
+      self.attributes = ActiveSupport::JSON.decode(json)
+      self
+    end
+
+    class JsonSerializer < ActiveRecord::Serialization::Serializer #:nodoc:
+      def serialize
+        serializable_record.to_json
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/serializers/xml_serializer.rb b/activerecord/lib/active_record/serializers/xml_serializer.rb
new file mode 100644
index 0000000000..1e4101f183
--- /dev/null
+++ b/activerecord/lib/active_record/serializers/xml_serializer.rb
@@ -0,0 +1,327 @@
+module ActiveRecord #:nodoc:
+  module Serialization
+    # Builds an XML document to represent the model.   Some configuration is
+    # availble through +options+, however more complicated cases should use 
+    # override ActiveRecord's to_xml.
+    #
+    # By default the generated XML document will include the processing 
+    # instruction and all object's attributes.  For example:
+    #    
+    #   <?xml version="1.0" encoding="UTF-8"?>
+    #   <topic>
+    #     <title>The First Topic</title>
+    #     <author-name>David</author-name>
+    #     <id type="integer">1</id>
+    #     <approved type="boolean">false</approved>
+    #     <replies-count type="integer">0</replies-count>
+    #     <bonus-time type="datetime">2000-01-01T08:28:00+12:00</bonus-time>
+    #     <written-on type="datetime">2003-07-16T09:28:00+1200</written-on>
+    #     <content>Have a nice day</content>
+    #     <author-email-address>david@loudthinking.com</author-email-address>
+    #     <parent-id></parent-id>
+    #     <last-read type="date">2004-04-15</last-read>
+    #   </topic>
+    #
+    # This behavior can be controlled with :only, :except,
+    # :skip_instruct, :skip_types and :dasherize.  The :only and
+    # :except options are the same as for the #attributes method.
+    # The default is to dasherize all column names, to disable this,
+    # set :dasherize to false.  To not have the column type included
+    # in the XML output, set :skip_types to true.
+    #
+    # For instance:
+    #
+    #   topic.to_xml(:skip_instruct => true, :except => [ :id, :bonus_time, :written_on, :replies_count ])
+    #
+    #   <topic>
+    #     <title>The First Topic</title>
+    #     <author-name>David</author-name>
+    #     <approved type="boolean">false</approved>
+    #     <content>Have a nice day</content>
+    #     <author-email-address>david@loudthinking.com</author-email-address>
+    #     <parent-id></parent-id>
+    #     <last-read type="date">2004-04-15</last-read>
+    #   </topic>
+    # 
+    # To include first level associations use :include
+    #
+    #   firm.to_xml :include => [ :account, :clients ]
+    #
+    #   <?xml version="1.0" encoding="UTF-8"?>
+    #   <firm>
+    #     <id type="integer">1</id>
+    #     <rating type="integer">1</rating>
+    #     <name>37signals</name>
+    #     <clients>
+    #       <client>
+    #         <rating type="integer">1</rating>
+    #         <name>Summit</name>
+    #       </client>
+    #       <client>
+    #         <rating type="integer">1</rating>
+    #         <name>Microsoft</name>
+    #       </client>
+    #     </clients>
+    #     <account>
+    #       <id type="integer">1</id>
+    #       <credit-limit type="integer">50</credit-limit>
+    #     </account>
+    #   </firm>
+    #
+    # To include any methods on the object(s) being called use :methods
+    #
+    #   firm.to_xml :methods => [ :calculated_earnings, :real_earnings ]
+    #
+    #   <firm>
+    #     # ... normal attributes as shown above ...
+    #     <calculated-earnings>100000000000000000</calculated-earnings>
+    #     <real-earnings>5</real-earnings>
+    #   </firm>
+    #
+    # To call any Proc's on the object(s) use :procs.  The Proc's
+    # are passed a modified version of the options hash that was
+    # given to #to_xml.
+    #
+    #   proc = Proc.new { |options| options[:builder].tag!('abc', 'def') }
+    #   firm.to_xml :procs => [ proc ]
+    #
+    #   <firm>
+    #     # ... normal attributes as shown above ...
+    #     <abc>def</abc>
+    #   </firm>
+    #
+    # Alternatively, you can also just yield the builder object as part of the to_xml call:
+    #
+    #   firm.to_xml do |xml|
+    #     xml.creator do
+    #       xml.first_name "David"
+    #       xml.last_name "Heinemeier Hansson"
+    #     end
+    #   end
+    #
+    #   <firm>
+    #     # ... normal attributes as shown above ...
+    #     <creator>
+    #       <first_name>David</first_name>
+    #       <last_name>Heinemeier Hansson</last_name>
+    #     </creator>
+    #   </firm>
+    #
+    # You may override the to_xml method in your ActiveRecord::Base
+    # subclasses if you need to.  The general form of doing this is
+    #
+    #   class IHaveMyOwnXML < ActiveRecord::Base
+    #     def to_xml(options = {})
+    #       options[:indent] ||= 2
+    #       xml = options[:builder] ||= Builder::XmlMarkup.new(:indent => options[:indent])
+    #       xml.instruct! unless options[:skip_instruct]
+    #       xml.level_one do
+    #         xml.tag!(:second_level, 'content')
+    #       end
+    #     end
+    #   end
+    def to_xml(options = {}, &block)
+      serializer = XmlSerializer.new(self, options)
+      block_given? ? serializer.to_s(&block) : serializer.to_s
+    end
+
+    def from_xml(xml)
+      self.attributes = Hash.from_xml(xml).values.first
+      self
+    end
+  end
+
+  class XmlSerializer < ActiveRecord::Serialization::Serializer #:nodoc:
+    def builder
+      @builder ||= begin
+        options[:indent] ||= 2
+        builder = options[:builder] ||= Builder::XmlMarkup.new(:indent => options[:indent])
+
+        unless options[:skip_instruct]
+          builder.instruct!
+          options[:skip_instruct] = true
+        end
+        
+        builder
+      end
+    end
+
+    def root
+      root = (options[:root] || @record.class.to_s.underscore).to_s
+      dasherize? ? root.dasherize : root
+    end
+    
+    def dasherize?
+      !options.has_key?(:dasherize) || options[:dasherize]
+    end
+
+
+    # To replicate the behavior in ActiveRecord#attributes,
+    # :except takes precedence over :only.  If :only is not set
+    # for a N level model but is set for the N+1 level models,
+    # then because :except is set to a default value, the second
+    # level model can have both :except and :only set.  So if
+    # :only is set, always delete :except.
+    def serializable_attributes
+      serializable_attribute_names.collect { |name| Attribute.new(name, @record) }
+    end
+
+    def serializable_method_attributes
+      Array(options[:methods]).inject([]) do |method_attributes, name|
+        method_attributes << MethodAttribute.new(name.to_s, @record) if @record.respond_to?(name.to_s)
+        method_attributes
+      end
+    end
+
+    def add_attributes
+      (serializable_attributes + serializable_method_attributes).each do |attribute|
+        add_tag(attribute)
+      end
+    end
+
+    def add_includes
+      if include_associations = options.delete(:include)
+        root_only_or_except = { :except => options[:except],
+                                :only => options[:only] }
+
+        include_has_options = include_associations.is_a?(Hash)
+
+        for association in include_has_options ? include_associations.keys : Array(include_associations)
+          association_options = include_has_options ? include_associations[association] : root_only_or_except
+
+          opts = options.merge(association_options)
+
+          case @record.class.reflect_on_association(association).macro
+          when :has_many, :has_and_belongs_to_many
+            records = @record.send(association).to_a
+            tag = association.to_s
+            tag = tag.dasherize if dasherize?
+            if records.empty?
+              builder.tag!(tag, :type => :array)
+            else
+              builder.tag!(tag, :type => :array) do
+                association_name = association.to_s.singularize
+                records.each do |record| 
+                  record.to_xml opts.merge(
+                    :root => association_name, 
+                    :type => (record.class.to_s.underscore == association_name ? nil : record.class.name)
+                  )
+                end
+              end
+            end
+          when :has_one, :belongs_to
+            if record = @record.send(association)
+              record.to_xml(opts.merge(:root => association))
+            end
+          end
+        end
+
+        options[:include] = include_associations
+      end
+    end
+
+    def add_procs
+      if procs = options.delete(:procs)
+        [ *procs ].each do |proc|
+          proc.call(options)
+        end
+      end
+    end
+
+
+    def add_tag(attribute)
+      builder.tag!(
+        dasherize? ? attribute.name.dasherize : attribute.name, 
+        attribute.value.to_s, 
+        attribute.decorations(!options[:skip_types])
+      )
+    end
+
+    def serialize
+      args = [root]
+      if options[:namespace]
+        args << {:xmlns=>options[:namespace]}
+      end
+      
+      if options[:type]
+        args << {:type=>options[:type]}
+      end
+        
+      builder.tag!(*args) do
+        add_attributes
+        add_includes
+        add_procs
+        yield builder if block_given?
+      end
+    end        
+
+    class Attribute #:nodoc:
+      attr_reader :name, :value, :type
+    
+      def initialize(name, record)
+        @name, @record = name, record
+      
+        @type  = compute_type
+        @value = compute_value
+      end
+
+      # There is a significant speed improvement if the value
+      # does not need to be escaped, as #tag! escapes all values
+      # to ensure that valid XML is generated.  For known binary
+      # values, it is at least an order of magnitude faster to
+      # Base64 encode binary values and directly put them in the
+      # output XML than to pass the original value or the Base64
+      # encoded value to the #tag! method. It definitely makes
+      # no sense to Base64 encode the value and then give it to
+      # #tag!, since that just adds additional overhead.
+      def needs_encoding?
+        ![ :binary, :date, :datetime, :boolean, :float, :integer ].include?(type)
+      end
+    
+      def decorations(include_types = true)
+        decorations = {}
+
+        if type == :binary
+          decorations[:encoding] = 'base64'
+        end
+      
+        if include_types && type != :string
+          decorations[:type] = type
+        end
+      
+        decorations
+      end
+    
+      protected
+        def compute_type
+          type = @record.class.serialized_attributes.has_key?(name) ? :yaml : @record.class.columns_hash[name].type
+
+          case type
+            when :text
+              :string
+            when :time
+              :datetime
+            else
+              type
+          end
+        end
+    
+        def compute_value
+          value = @record.send(name)
+        
+          if formatter = Hash::XML_FORMATTING[type.to_s]
+            value ? formatter.call(value) : nil
+          else
+            value
+          end
+        end
+    end
+
+    class MethodAttribute < Attribute #:nodoc:
+      protected
+        def compute_type
+          Hash::XML_TYPE_NAMES[@record.send(name).class.name] || :string
+        end
+    end
+  end
+end