lib/json_builder/template.rb
module ActionView #:nodoc:
  class Base
    cattr_accessor :pretty_print_json
    @@pretty_print_json = defined?(Rails) && Rails.env.development?

    cattr_accessor :json_callback
    @@json_callback = true
  end
end

# Rails 2.X Template
if defined?(Rails) && Rails.version.starts_with?('2')
  require 'action_view/base'
  require 'action_view/template'

  module ActionView
    module TemplateHandlers
      class JSONBuilder < TemplateHandler
        include Compilable

        def compile(template) %{
          ::JSONBuilder::Compiler.generate(:scope => self, :pretty => ActionView::Base.pretty_print_json, :callback => ActionView::Base.json_callback) {
            #{template.source}
          }
        } end
      end
    end
  end

  ActionView::Template.register_template_handler :json_builder, ActionView::TemplateHandlers::JSONBuilder
end

# Rails 3.X and 4.X Template
if defined?(Rails) && Rails.version.starts_with?('3', '4')
  module ActionView
    module Template::Handlers
      class JSONBuilder
        class_attribute :default_format
        self.default_format = Mime::JSON

        def self.call(template)
          source = if template.source.empty?
            File.read(template.identifier)
          else # use source
            template.source
          end

          %{
            ::JSONBuilder::Compiler.generate(:scope => self, :pretty => ActionView::Base.pretty_print_json, :callback => ActionView::Base.json_callback) {
              #{source}
            }
          }
        end
      end
    end
  end

  ActionView::Template.register_template_handler :json_builder, ActionView::Template::Handlers::JSONBuilder
end
