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:
#
# <?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 <tt>:only</tt>, <tt>:except</tt>,
# <tt>:skip_instruct</tt>, <tt>:skip_types</tt> and <tt>:dasherize</tt>.
# The <tt>:only</tt> and <tt>:except</tt> options are the same as for the
# +attributes+ method. The default is to dasherize all column names, but you
# can disable this setting <tt>:dasherize</tt> to +false+. To not have the
# column type included in the XML output set <tt>:skip_types</tt> 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 <tt>:include</tt>:
#
# 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 type="array">
# <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 deeper levels of associations pass a hash like this:
#
# firm.to_xml :include => {:account => {}, :clients => {:include => :address}}
# <?xml version="1.0" encoding="UTF-8"?>
# <firm>
# <id type="integer">1</id>
# <rating type="integer">1</rating>
# <name>37signals</name>
# <clients type="array">
# <client>
# <rating type="integer">1</rating>
# <name>Summit</name>
# <address>
# ...
# </address>
# </client>
# <client>
# <rating type="integer">1</rating>
# <name>Microsoft</name>
# <address>
# ...
# </address>
# </client>
# </clients>
# <account>
# <id type="integer">1</id>
# <credit-limit type="integer">50</credit-limit>
# </account>
# </firm>
#
# To include any methods on the model being called use <tt>:methods</tt>:
#
# 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 additional Procs use <tt>:procs</tt>. 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 ]
#
# <firm>
# # ... normal attributes as shown above ...
# <abc>def</abc>
# </firm>
#
# 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
#
# <firm>
# # ... normal attributes as shown above ...
# <creator>
# <first_name>David</first_name>
# <last_name>Heinemeier Hansson</last_name>
# </creator>
# </firm>
#
# 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 <tt>tag!</tt> 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 <tt>tag!</tt> method. It definitely makes
# no sense to Base64 encode the value and then give it to
# <tt>tag!</tt>, 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
