The flash provides a way to pass temporary primitive-types (String
, Array
, Hash
) 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.
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
end
end
show.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:
flash.alert = "You must be logged in"
flash.notice = "Post successfully created"
This example places a string in the flash. And of course, you can put as many as you like at a time too. If you want to pass non-primitive types, you will have to handle that in your application. Example: To show messages with links, you will have to use sanitize helper.
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.
- N
Constants
KEY | = | "action_dispatch.request.flash_hash" |