Jsonifier
=========

Adds options to the ActiveRecord#to_json method similar to ActiveRecord#to_xml.
The :only, :except, :methods, and :include options are supported.

ActiveRecord#to_json will no longer return you "attributes" as part of the JSON - i.e. no more

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

The 'attributes' part is often unnecessary cruft when consuming ActiveRecord objects as JSON.

You get this instead:

  {id: 1, name: "Konata"}

Assuming User and Post models where User has_many Posts:

  david = User.find(1)
  david.to_json  # {id: 1, name: "David", awesome: true, created_at: "07/01/2007"}

By the way, the created_at date attribute is in MM/DD/YYYY format (which is evil in my opinion for
being US-centric but that's another matter).

OK some examples. :only and :except work the same way that as for ActiveRecord#to_xml:

  david.to_json(:only => :name)                 # {name: "David"}
  david.to_json(:only => [:id, :name])          # {id: 1, name: "David"}
  david.to_json(:except => :created_at)         # {id: 1, name: "David", awesome: true}
  david.to_json(:except => [:id, :created_at])  # {name: "David", awesome: true}

You can use the :methods options as well to include any methods on the object.

  david.to_json(:methods => :permalink)
    # {id: 1, name: "David", awesome: true, created_at: "07/01/2007", permalink => "1-David"}
  david.to_json(:methods => [:permalink, :interestingness])
    # {id: 1, name: "David", awesome: true, created_at: "07/01/2007", \
        permalink => "1-David", :interestingness => 666}

The :include option lets you include associations.

  david.to_json(:include => :posts)
    # {id: 1, name: "David", awesome: true, created_at: "07/01/2007", \
         posts: [{id: 1, author_id: 1, title: "Welcome to the weblog"}, \
                 {id: 2, author_id: 1, title: "So I was thinking"}]}

:only, :except, and :methods works on the included associations as well:

  david.to_json(:include => { :posts => { :only => :title } })
    # {id: 1, name: "David", awesome: true, created_at: "07/01/2007", \
         posts: [{title: "Welcome to the weblog"}, \
                 {title: "So I was thinking"}]}

Of course, 2nd level (and higher order) associations work too:

  david.to_json(:include => { :posts => { \
                                :include => { :comments => { \
                                                :only => :body } }, \
                                :only => :title } })
    # {id: 1, name: "David", awesome: true, created_at: "07/01/2007", \
         posts: [{comments: [{body: "1st post!"}, {body: "OMGWTFBBQ!"}], \
                  title: "Welcome to the weblog"}, \
                 {comments: [{body: "Don't think too hard"}], \
                  title: "So I was thinking"}]}

Check out Rails patch for more details and tests (which I intend to add to the plugin real soon!):
http://dev.rubyonrails.org/ticket/8920


A note on valid JSON
--------------------

Note: the JSON Rails spits out by default is not strictly valid JSON since the JSON
specifications require keys to be double quoted. To get strictly valid JSON, add

  ActiveSupport::JSON.unquote_hash_key_identifiers = false

in your environment.rb (or in the Rails initializers directory if you're on edge).
See http://blog.codefront.net/2007/06/20/how-to-get-strictly-valid-json-from-rails/ for more info.


Copyright (c) 2007 Cheah Chu Yeow, released under the MIT license