What does .flashing do in Play!2?

Question

Can someone explain what the Flash Scope is? What does .flashing() do and how to use both of them?

Answer 1

Roughly flashing is useful in the cases you need a temporary parameter. Common case is a message to be displayed to the next page accessed using a redirect

This is very useful when you need information part of a workflow but which you don't want them to be part of the contract declared by a template (parameters).

A flashed information is stored in the cookie not hashed (in clear thus) and its lifetime is scoped to the very next request -- discarded after.

The way to use flashing is simply use flashing which a sequence of strings kvp, like so Redirect(routes.Application.login()).flashing("error", "You must be logged in")

Where login is using a template to be rendered which contains @flash.get("error") map { x => @x }