The flash provides a way to pass temporary objects between actions.
Anything you place in the flash will be exposed to the very next action and
then cleared out. This is a great way of doing notices and alerts, such as
a create action that sets flash[:notice] = "Post successfully
created" before redirecting to a display action that can then
expose the flash to its template. Actually, that exposure is automatically
done.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | class PostsController < ActionController::Base def create # save post flash[:notice] = "Post successfully created" redirect_to @post end def show # doesn't need to assign the flash notice to the template, that's done automatically endendshow.html.erb <% if flash[:notice] %> <div class="notice"><%= flash[:notice] %></div> <% end %> |
Since the notice and alert keys are a common
idiom, convenience accessors are available:
1 2 | flash.alert = "You must be logged in"flash.notice = "Post successfully created" |
This example just places a string in the flash, but you can put any object in there. And of course, you can put as many as you like at a time too. Just remember: They'll be gone by the time the next action has been performed.
See docs on the FlashHash class for more details about the flash.