JSON Builder [![Build Status](https://secure.travis-ci.org/dewski/json_builder.png)](http://travis-ci.org/dewski/json_builder) ============ Rails provides an excellent XML Builder by default to build RSS and ATOM feeds, but nothing to help you build complex and custom JSON data structures. The standard `to_json` works just fine, but can get very verbose when you need full control of what is generated and performance is a factor. JSON Builder hopes to solve that problem. ## Sample Usage ```ruby require 'json_builder' json = JSONBuilder::Compiler.generate do name 'Garrett Bjerkhoel' email 'spam@garrettbjerkhoel.com' url root_path address do street '1234 1st Ave' street2 'Apt 1' city 'New York' state 'NY' zip 10065 end key :nil, 'testing a custom key name' skills do ruby true asp false end longstring do # Could be a highly intensive process that only returns a string '12345' * 25 end end ``` Which will generate: ```json { "name": "Garrett Bjerkhoel", "email": "spam@garrettbjerkhoel.com", "url": "/", "address": { "street": "1234 1st Ave", "street2": "Apt 1", "city": "New York", "state": "NY", "zip": 10065 }, "nil": "testing a custom key name", "skills": { "ruby": true, "asp": false }, "longstring": "1234512345123451234512345..." } ``` If you'd like to just generate an array: ```ruby array ['Garrett Bjerkhoel', 'John Doe'] do |name| first, last = name.split(' ') first first last last end ``` Which will output the following: ```json [ { "first": "Garrett", "last": "Bjerkhoel" }, { "first": "John", "last": "Doe" } ] ``` Just a note, if you use an array block, all other builder methods will be ignored. ## Using JSON Builder with Rails First, make sure to add the gem to your `Gemfile`. ```ruby gem 'json_builder' ``` Second, make sure your controller responds to `json`: ```ruby class UsersController < ApplicationController respond_to :json def index @users = User.order('id DESC').page(params[:page]).per(2) respond_with @users end end ``` Lastly, create `app/views/users/index.json.json_builder` which could look something like: ```ruby count @users.count page @users.current_page per_page @users.per_page pages_count @users.num_pages results @users do |user| id user.id name user.name body user.body url user_url(user) links user.links do |link| url link.url visits link.visits last_visited link.last_visited end end ``` You will get something like: ```json { "count": 10, "page": 1, "per_page": 2, "pages_count": 5, "results": [ { "id": 1, "name": "Garrett Bjerkhoel", "body": "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod.", "url": "http://example.com/users/garrett-bjerkhoel", "links": [ { "url": "http://github.com/", "visits": 500, "last_visited": "2011-11-271T00:00:01Z" }, { "url": "http://garrettbjerkhoel.com/", "visits": 1500, "last_visited": "2011-11-261T00:00:01Z" } ] }, { "id": 2, "name": "John Doe", "body": "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod.", "url": "http://example.com/users/john-doe", "links": [ { "url": "http://google.com/", "visits": 11000, "last_visited": "2010-05-221T00:00:01Z" }, { "url": "http://twitter.com/", "visits": 155012857, "last_visited": "2011-11-261T00:00:01Z" } ] } ] } ``` ### Including JSONP callbacks Out of the box JSON Builder supports JSONP callbacks when used within a Rails project just by using the `callback` parameter. For instance, if you requested `/users.json?callback=myjscallback`, you'll get a callback wrapping the response: ```json myjscallback([ { "name": "Garrett Bjerkhoel" }, { "name": "John Doe" } ]) ``` To turn off JSONP callbacks globally or just per-environment: #### Globally ```ruby ActionView::Base.json_callback = false ``` #### Per Environment ```ruby Sample::Application.configure do config.action_view.json_callback = false end ``` ### Pretty Print Output Out of the box JSON Builder supports pretty printing only during development, it's disabled by default in other environments for performance. If you'd like to enable or disable pretty printing you can do it within your environment file or you can do it globally. With pretty print on: ```json { "name": "Garrett Bjerkhoel", "email": "spam@garrettbjerkhoel.com" } ``` Without: ```json {"name": "Garrett Bjerkhoel", "email": "spam@garrettbjerkhoel.com"} ``` #### Per Environment ```ruby Sample::Application.configure do config.action_view.pretty_print_json = false end ``` #### Globally ```ruby ActionView::Base.pretty_print_json = false ``` ## Speed JSON Builder is very fast, it's roughly 3.6 times faster than the core XML Builder based on the [speed benchmark](http://github.com/dewski/json_builder/blob/master/spec/benchmarks/builder.rb). user system total real JSONBuilder 2.950000 0.010000 2.960000 (2.968790) Builder 10.820000 0.040000 10.860000 (10.930497) ## Alternative libraries There are alternatives to JSON Builder, each good in their own way with different API's and design approaches that are worth checking out. Although, I would love to hear why JSON Builder didn't fit your needs, by [message or issue. * [jbuilder](https://github.com/rails/jbuilder) * [RABL](https://github.com/nesquena/rabl) * [Tequila](https://github.com/inem/tequila) * [Argonaut](https://github.com/jbr/argonaut) * [Jsonify](https://github.com/bsiggelkow/jsonify) * [RepresentationView](https://github.com/mdub/representative_view) ## Note on Patches/Pull Requests - Fork the project. - Make your feature addition or bug fix. - Add tests for it. This is important so I don't break it in a future version unintentionally. - Commit, do not mess with Rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself in another branch so I can ignore when I pull) - Send me a pull request. Bonus points for topic branches. ## Copyright Copyright © 2012 Garrett Bjerkhoel. See [MIT-LICENSE](http://github.com/dewski/json_builder/blob/master/MIT-LICENSE) for details.