Module: ActiveRecord::Serialization

Defined in:
lib/active_record/serialization.rb,
lib/active_record/serializers/xml_serializer.rb,
lib/active_record/serializers/json_serializer.rb

Defined Under Namespace

Classes: JsonSerializer, Serializer

Instance Method Summary collapse

Instance Method Details

#from_json(json) ⇒ Object 



60
61
62
63
 
# File 'lib/active_record/serializers/json_serializer.rb', line 60

def from_json(json)
  self.attributes = ActiveSupport::JSON.decode(json)
  self
end

#from_xml(xml) ⇒ Object 



128
129
130
131
 
# File 'lib/active_record/serializers/xml_serializer.rb', line 128

def from_xml(xml)
  self.attributes = Hash.from_xml(xml).values.first
  self
end

#to_json(options = {}) ⇒ Object

Returns a JSON string representing the model. Some configuration is available through options.

Without any options, the returned JSON string will include all the model's attributes. For example:

konata = User.find(1)
konata.to_json

{"id": 1, "name": "Konata Izumi", "age": 16,
"created_at": "2006/08/01", "awesome": true}

The :only and :except options can be used to limit the attributes included, and work similar to the #attributes method. For example:

konata.to_json(:only => [ :id, :name ])

{"id": 1, "name": "Konata Izumi"}

konata.to_json(:except => [ :id, :created_at, :age ])

{"name": "Konata Izumi", "awesome": true}

To include any methods on the model, use :methods.

konata.to_json(:methods => :permalink)

{"id": 1, "name": "Konata Izumi", "age": 16,
"created_at": "2006/08/01", "awesome": true,
"permalink": "1-konata-izumi"}

To include associations, use :include.

konata.to_json(:include => :posts)

{"id": 1, "name": "Konata Izumi", "age": 16,
"created_at": "2006/08/01", "awesome": true,
"posts": [{"id": 1, "author_id": 1, "title": "Welcome to the weblog"},
         {"id": 2, author_id: 1, "title": "So I was thinking"}]}

2nd level and higher order associations work as well:

konata.to_json(:include => { :posts => {
                             :include => { :comments => {
                                           :only => :body } },
                             :only => :title } })

{"id": 1, "name": "Konata Izumi", "age": 16,
"created_at": "2006/08/01", "awesome": true,
"posts": [{"comments": [{"body": "1st post!"}, {"body": "Second!"}],
          "title": "Welcome to the weblog"},
         {"comments": [{"body": "Don't think too hard"}],
          "title": "So I was thinking"}]}


56
57
58
 
# File 'lib/active_record/serializers/json_serializer.rb', line 56

def to_json(options = {})
  JsonSerializer.new(self, options).to_s
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'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 [email protected] 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 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

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

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
# ... normal attributes as shown above ... David Heinemeier Hansson

You can 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


123
124
125
126
 
# File 'lib/active_record/serializers/xml_serializer.rb', line 123

def to_xml(options = {}, &block)
  serializer = XmlSerializer.new(self, options)
  block_given? ? serializer.to_s(&block) : serializer.to_s
end