Sinatra flash

flash.rb

module Sinatra
  module Flash
    module InstanceMethods
      def flash
        @flash ||= {}
      end
      
      def flash_now
        @flash_now ||= {}
      end
      
      def redirect(uri, *args)
        session[:flash] = flash
        super(uri, *args)
      end
    end
    
    def self.registered(app)
      app.before { flash.merge!(session.delete('flash') || {}) }
      app.helpers InstanceMethods
    end
  end
end

flash_spec.rb

require_relative 'spec_helper'

describe Sinatra::Flash do
  
  def app
    Sinatra.new do
      enable :sessions
      register Sinatra::Flash
      get '/' do
        flash.inspect
      end
      
      get '/flash' do
        flash[:notice] = 'foo'
        redirect to '/'
      end
      
      get '/flash_now' do
        flash_now[:notice] = 'foo'
        flash_now.inspect
      end
      
      get '/flash_now_redirect' do
        flash_now[:notice] = 'foo'
        redirect to '/'
      end
    end
  end
  
  describe 'flash' do
    it 'must be empty by default' do
      get '/'
      last_response.body.must_equal '{}'
    end
    
    it 'must persist across requests' do
      get '/flash'
      follow_redirect!
      last_response.body.must_equal "{:notice=>\"foo\"}"
    end
  end
  
  describe 'flash_now' do
    it 'must set and return a hash' do
      get '/flash_now'
      last_response.body.must_equal "{:notice=>\"foo\"}"
    end
    
    it 'must not persist across requests' do
      get '/flash_now_redirect'
      follow_redirect!
      last_response.body.must_equal '{}'
    end
  end
end