Roll Your Own Session Based Flash Messaging w/ Sinatra

Session based flash messages are fairly common in web apps. They work well when you have a temporary status to report back to the user, such as successfully saving a form. If you use Rails it comes with the Framework. If you are using Sinatra there are a few Rack based plugins. But it's fairly trivial to write yourself. And you don't add a lot of complexity to your project. The trick is to unset the key when you get the value for display. This way no message will be seen on the next request. # Simple flash messages # flash = FlashMessage.new(session) # flash.message = 'hello world' # flash.message # => 'hello world' # flash.message # => nil class FlashMessage def initialize(session) @session ||= session end def message=(message) @session[:flash] = message end def message message = @session[:flash] #tmp get the value @session[:flash] = nil # unset the value message # display the value end end If you're using Sinatra, in the helpers block you can create a method for quick access in your routes and views. configure do enable :sessions end helpers do def flash @flash ||= FlashMessage.new(session) end end # a few routes get '/' do flash.message = 'Hello World' redirect '/flash' end get '/flash' do erb :index end # views/flash.erb <%= flash.message %> As you can see it's pretty straight forward. You can also be a little more creative if you take this approach and implement it yourself. For instance, you could additional methods for different types of flash messages with logging. Or maybe you could add a second parameter, a counter, that will display a flash message n number of times before popping it off the stack...

flash.message=('Remember to reset your password', 10)