Module: ActiveRecord::Serialization

Extended by:
ActiveSupport::Concern
Includes:
ActiveModel::Serializers::JSON, ActiveModel::Serializers::Xml
Included in:
Base
Defined in:
lib/active_record/serialization.rb,
lib/active_record/serializers/xml_serializer.rb

Overview

Active Record Serialization

Instance Method Summary collapse

Instance Method Details

#serializable_hash(options = nil) ⇒ Object 



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# File 'lib/active_record/serialization.rb', line 11

def serializable_hash(options = nil)
  options = options.try(:clone) || {}

  options[:except] = Array(options[:except]).map { |n| n.to_s }
  options[:except] |= Array(self.class.inheritance_column)

  super(options)
end

#to_xml(options = {}, &block) ⇒ Object

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 [email protected] 2004-04-15

This behavior can be controlled with :only, :except, :skip_instruct, :skip_types, :dasherize and :camelize . 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. Setting :camelize to true will camelize all column names - this also overrides :dasherize. 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 [email protected] 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

Additionally, the record being serialized will be passed to a Proc's second parameter. This allows for ad hoc additions to the resultant document that incorporate the context of the record being serialized. And by leveraging the closure created by a Proc, to_xml can be used to add elements that normally fall outside of the scope of the model -- for example, generating and appending URLs associated with models.

proc = Proc.new { |options, record| options[:builder].tag!('name-reverse', record.name.reverse) }
firm.to_xml procs: [ proc ]
# ... normal attributes as shown above ... slangis73

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 :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 = {})
  require 'builder'
  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


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# File 'lib/active_record/serializers/xml_serializer.rb', line 174

def to_xml(options = {}, &block)
  XmlSerializer.new(self, options).serialize(&block)
end