River

River renders JSON to a stream using the batch iteration

Installation

Add this line to your application's Gemfile:

gem 'river', github: 'undr/river'

And then execute:

$ bundle

Usage

class HomeController < ApplicationController
  before_filter :find_pages

  def stream
    stream_json_in_batches(@pages, batch_size: 2)
  end

  def chunked_stream
    stream_json_in_batches(@pages, chunked: true, batch_size: 2)
  end

  private

  def find_pages
    @pages = Page.where('id < 10')
  end
end

Or:

class HomeController < ApplicationController
  respond_to :json

  before_filter :find_pages

  def stream
    respond_with(@pages, in_batches: { batch_size: 2 })
  end

  def chunked_stream
    respond_with(@pages, in_batches: { chunked: true, batch_size: 2 })
  end

  private

  def find_pages
    @pages = Page.where('id < 10')
  end
end

Chunked JSON:

undr$ telnet localhost 3000
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
GET /chunked_stream
33f
[{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":1,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":2,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"}]
33f
[{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":3,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":4,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"}]
33f
[{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":5,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":6,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"}]
33f
[{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":7,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":8,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"}]
1a0
[{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":9,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"}]
0

Not chunked JSON:

undr$ telnet localhost 3000
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
GET /stream
[{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":1,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":2,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":3,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":4,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":5,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":6,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":7,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":8,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"},{"body":"<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin risus. Praesent lectus.</p>","created_at":"2013-08-26T20:11:11Z","id":9,"title":"Lorem Ipsum Dolor Sit Amet, Consectetuer Adipiscing Elit","updated_at":"2013-08-26T20:11:11Z"}]

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request