sbf-dm-serializer

= dm-serializer

== Overview

dm-serializer allows DataMapper models and collections to be serialized to a variety of formats (currently JSON, XML, YAML and CSV).

== How it works

One method is added to each model/collection for each serialization type - to_json, to_xml, to_yaml, and to_csv. With the exception of to_csv, all of these methods share the same interface. to_json will be used for examples. Any method specific behaviour is documented in its own section below.

require 'dm-serializer'

class Cow include DataMapper::Resource

property :id,   Integer, :key => true
property :name, String

def description
  "A Cow"
end

end

cow = Cow.create( :id => 1, :name => "Berta" )

cow.to_json # => { "id": 1, "name": "Berta" } cow.to_json(:only => [:name]) # => { "name": "Berta" } cow.to_json(:exclude => [:id]) # => { "name": "Berta" } cow.to_json(:methods => [:description]) # => { "id": 1, "name": "Berta", "description": "A Cow" }

You can include associations by passing the association accessor the :methods option.

If you want to only load a particular serialization method, that's cool, you can do that:

require 'dm-serializer/to_json'

== to_xml

to_xml supports some extra options to allow you to override the element names

cow.to_xml(:element_name => 'bovine') # => 1Berta cows.to_xml(:collection_element_name => 'kine') # => 1Berta

If you would like a nice speed boost (~5x), require libxml or nokogiri before dm-serializer, and that library will be used rather than REXML.

== to_csv

to_csv currently doesn't support any options yet. It will in the future. It will not support serializing child associations.

== Arrays, Hashes, and other core classes

dm-serializer only adds serialization methods to DataMapper objects and collections, however some libraries used (json, yaml) add methods to core classes, such as Array. Note that passing dm-serializer options (such as :only) to these methods is not supported.

Cow.all.to_a.to_yaml(:only => 'name') # WILL NOT WORK

== Beware

If you go spelunking through the code you will find other undocumented options. Use at your own risk, I plan on removing or changing these in the near future.