class ActionDispatch::Flash

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

def call(env) 

def call(env)
  @app.call(env)
ensure
  session    = Request::Session.find(env) || {}
  flash_hash = env[KEY]
  if flash_hash && (flash_hash.present? || session.key?('flash'))
    session["flash"] = flash_hash.to_session_value
    env[KEY] = flash_hash.dup
  end
  if (!session.respond_to?(:loaded?) || session.loaded?) && # (reset_session uses {}, which doesn't implement #loaded?)
    session.key?('flash') && session['flash'].nil?
    session.delete('flash')
  end
end

def initialize(app) 

def initialize(app)
  @app = app
end