tilt-jbuilder.rb

# This class is used to render jbuilder templates in grape.
#
# There is an existing grape-jbuilder gem but it depends
# on tilt-jbuilder gem which
# - does not support partial! with :collection
# - does not support template compilation
#
# In constrast this template handler supports all features of jbuilder
# and uses template compilation (5x-10x times faster than without).
class Tilt::Jbuilder < Tilt::Template
  class Context < SimpleDelegator
    def render(options)
      render_partial options
    end
  end
 
  def prepare
  end
 
  def file
    File.join options.fetch(:view_path, '.'), super
  end
 
  def render(scope=Object.new, locals={})
    options[:scope] = scope
    locals[:jbuilder] = self
    super
  end
 
  def render_partial(options={})
    partial = options[:partial].sub /\w+$/, '_\0.jbuilder'
    builder = Tilt::Jbuilder.new partial, @options.merge(partial: true)
    builder.render @options[:scope], options[:locals]
  end
 
  def precompiled_preamble(_)
    <<-RUBY
      #{super}
      json ||= JbuilderTemplate.new(Tilt::Jbuilder::Context.new jbuilder)
    RUBY
  end
 
  def precompiled_template(_)
    data
  end
 
  def precompiled_postamble(_)
    'json.target!' unless options[:partial]
  end
end