module ActiveRecord #:nodoc: module Serialization # Builds an XML document to represent the model. Some configuration is # available through +options+. However more complicated cases should # override ActiveRecord::Base#to_xml. # # By default the generated XML document will include the processing # instruction and all the object's attributes. For example: # # # # The First Topic # David # 1 # false # 0 # 2000-01-01T08:28:00+12:00 # 2003-07-16T09:28:00+1200 # Have a nice day # david@loudthinking.com # # 2004-04-15 # # # 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, but you # can disable this setting :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 ]) # # # The First Topic # David # false # Have a nice day # david@loudthinking.com # # 2004-04-15 # # # To include first level associations use :include: # # firm.to_xml :include => [ :account, :clients ] # # # # 1 # 1 # 37signals # # # 1 # Summit # # # 1 # Microsoft # # # # 1 # 50 # # # # To include deeper levels of associations pass a hash like this: # # firm.to_xml :include => {:account => {}, :clients => {:include => :address}} # # # 1 # 1 # 37signals # # # 1 # Summit #
# ... #
#
# # 1 # Microsoft #
# ... #
#
#
# # 1 # 50 # #
# # To include any methods on the model being called use :methods: # # firm.to_xml :methods => [ :calculated_earnings, :real_earnings ] # # # # ... normal attributes as shown above ... # 100000000000000000 # 5 # # # To call any additional Procs use :procs. The Procs 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 ] # # # # ... normal attributes as shown above ... # def # # # Alternatively, you can 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 # # # # ... normal attributes as shown above ... # # David # Heinemeier Hansson # # # # As noted above, you may override +to_xml+ in your ActiveRecord::Base # subclasses to have complete control about what's generated. 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 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_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 add_associations(association, records, opts) if records.is_a?(Enumerable) 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 else if record = @record.send(association) record.to_xml(opts.merge(:root => association)) end end 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 procs = options.delete(:procs) add_includes { |association, records, opts| add_associations(association, records, opts) } options[:procs] = procs 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 if value.nil? decorations[:nil] = true 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