module ActiveRecord #:nodoc: module XmlSerialization # 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: # # # # 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, to disable this, # set :dasherize to false. To not have the column type included # in the XML output, set :skip_types to false. # # 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 any methods on the object(s) being called use :methods # # firm.to_xml :methods => [ :calculated_earnings, :real_earnings ] # # # # ... normal attributes as shown above ... # 100000000000000000 # 5 # # # 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 ] # # # # ... normal attributes as shown above ... # def # # # 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 = {}) XmlSerializer.new(self, options).to_s end end class XmlSerializer #:nodoc: attr_reader :options def initialize(record, options = {}) @record, @options = record, options end 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 attribute_names = @record.attribute_names if options[:only] options.delete(:except) attribute_names = attribute_names & Array(options[:only]).collect { |n| n.to_s } else options[:except] = Array(options[:except]) | Array(@record.class.inheritance_column) attribute_names = attribute_names - options[:except].collect { |n| n.to_s } end attribute_names.collect { |name| Attribute.new(name, @record) } end def serializable_method_attributes Array(options[:methods]).collect { |name| MethodAttribute.new(name.to_s, @record) } 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 unless records.empty? tag = records.first.class.to_s.underscore.pluralize tag = tag.dasherize if dasherize? builder.tag!(tag) do records.each { |r| r.to_xml(opts.merge(:root => association.to_s.singularize)) } 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 builder.tag!(root) do add_attributes add_includes add_procs end end alias_method :to_s, :serialize 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.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] || :string end end end end