Padrino is a modular framework. As such, you can leverage other libraries such as Sinatra libraries which complement Padrino quite well.
First you must reference sinatra-contrib in your Gemfile:
#Gemfile
source :rubygems
# Server requirements
# gem 'thin' # or mongrel
# gem 'trinidad', :platform => 'jruby'
# Project requirements
gem 'rake'
gem 'sinatra-flash', :require => 'sinatra/flash'
# Component requirements
gem 'haml'
# Test requirements
# Padrino Stable Gem
gem 'padrino', :path => '~/Desktop/code/padrino-framework'
# Or Padrino Edge
# gem 'padrino', :git => 'git://github.com/padrino/padrino-framework.git'
# Or Individual Gems
# %w(core gen helpers cache mailer admin).each do |g|
# gem 'padrino-' + g, '0.10.7'
# end
gem 'sinatra-contrib'
You may use the #json method after you have registered the sinatra helper:
class MyJsonApp < Padrino::Application
register Padrino::Rendering
register Padrino::Mailer
register Padrino::Helpers
helpers Sinatra::JSON
enable :sessions
get '/' do
hash = {foo: 'bar'}
json hash
end
end