ActionDispatch::Flash (original) (raw)

Action Dispatch Flash

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

flash[:notice] = "Post successfully created"
redirect_to @post

end

def show

end end

Then in show.html.erb:

<% if flash[:notice] %>

<%= flash[:notice] %>
<% 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.

Namespace

Methods

N

Constants

KEY = "action_dispatch.request.flash_hash"

Class Public methods