| Module | ActionController::Flash |
| In: |
vendor/rails/actionpack/lib/action_controller/flash.rb
|
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] = "Successfully created" before redirecting to a display action that can then expose the flash to its template. Actually, that exposure is automatically done. Example:
class WeblogController < ActionController::Base
def create
# save post
flash[:notice] = "Successfully created post"
redirect_to :action => "display", :params => { :id => post.id }
end
def display
# doesn't need to assign the flash notice to the template, that's done automatically
end
end
display.erb
<% if flash[:notice] %><div class="notice"><%= flash[:notice] %></div><% end %>
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.
# File vendor/rails/actionpack/lib/action_controller/flash.rb, line 27
27: def self.included(base)
28: base.class_eval do
29: include InstanceMethods
30: alias_method_chain :assign_shortcuts, :flash
31: alias_method_chain :process_cleanup, :flash
32: alias_method_chain :reset_session, :flash
33: end
34: end