Working With Rails

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© 2007 Cheah Chu Yeow, released under the MIT license

NOTE: This description has been extracted from the Plugin README and so the formatting may need updating to make browser friendly