class RodaSessionMiddleware

See Roda::RodaPlugins::Sessions for details on options.
that uses Roda’s sessions plugin for encrypted and signed cookies.
Session middleware that can be used in any Rack application

def call(env)

returned, then persist the session in the cookie.
application, and if the session has been loaded after the result has been
Initialize the session hash in the environment before calling the next 
def call(env)
  session = env['rack.session'] = SessionHash.new(@req_class.new(nil, env))
  res = @app.call(env)
  if session.loaded?
    session.req.persist_session(res[1], session.data)
  end
  res
end

def initialize(app, opts)

Setup the middleware, passing +opts+ as the Roda sessions plugin options. 
def initialize(app, opts)
  mid = Class.new(Roda)
  mid.plugin :sessions, opts
  @req_class = mid::RodaRequest
  @req_class.send(:include, RequestMethods)
  @app = app
end