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 posts_path(@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. Example:
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)
  if (session = env['rack.session']) && (flash = session['flash'])
    flash.sweep
  end
  @app.call(env)
ensure
  session    = env['rack.session'] || {}
  flash_hash = env[KEY]
  if flash_hash
    if !flash_hash.empty? || session.key?('flash')
      session["flash"] = flash_hash
      new_hash = flash_hash.dup
    else
      new_hash = flash_hash
    end
    env[KEY] = new_hash
  end
  if session.key?('flash') && session['flash'].empty?
    session.delete('flash')
  end
end

def initialize(app) 

def initialize(app)
  @app = app
end