Mount Sinatra subclasses

app.rb

require 'sinatra/base'

class Sinatra::Base
  def self.mount(klass, route="/#{klass.name.downcase}s")
    before "#{route}/*" do
      halt klass.call(
        env.merge!(
          'SCRIPT_NAME'             => route,
          'PATH_INFO'               => params.delete('splat').join('/'),
          'rack.request.query_hash' => params
        )
      )
    end
  end
end

class Foo < Sinatra::Base
  mount Foo, '/baz' # nest
  
  %w{get post put delete patch options}.each do |method|
    self.send method.to_sym, '/:foo_id' do
      "#{method}: #{params}"
    end
  end
end

class Bar < Sinatra::Base  
  get '/' do
    'index'
  end
  
  mount Foo, '/:bar_id/foos'
  
  run!
end