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:
#
# <?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 false.
#
# 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
end
class XmlSerializer #:nodoc:
attr_reader :options
def initialize(record, options = {})
@record, @options = record, options.dup
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 = association.to_s
tag = tag.dasherize if dasherize?
builder.tag!(tag) do
records.each { |r| r.to_xml(opts.merge(:root=>r.class.to_s.underscore)) }
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
builder.tag!(*args) do
add_attributes
add_includes
add_procs
yield builder if block_given?
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.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
