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module ActionController #:nodoc:
# 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 <tt>flash[:notice] = "Successfully created"</tt> 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.rhtml
# <% 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.
module Flash
def self.included(base)
base.send :include, InstanceMethods
base.class_eval do
alias_method_chain :assign_shortcuts, :flash
alias_method_chain :process_cleanup, :flash
alias_method_chain :reset_session, :flash
end
end
class FlashNow #:nodoc:
def initialize(flash)
@flash = flash
end
def []=(k, v)
@flash[k] = v
@flash.discard(k)
v
end
def [](k)
@flash[k]
end
end
class FlashHash < Hash
def initialize #:nodoc:
super
@used = {}
end
def []=(k, v) #:nodoc:
keep(k)
super
end
def update(h) #:nodoc:
h.keys.each{ |k| discard(k) }
super
end
alias :merge! :update
def replace(h) #:nodoc:
@used = {}
super
end
# Sets a flash that will not be available to the next action, only to the current.
#
# flash.now[:message] = "Hello current action"
#
# This method enables you to use the flash as a central messaging system in your app.
# When you need to pass an object to the next action, you use the standard flash assign (<tt>[]=</tt>).
# When you need to pass an object to the current action, you use <tt>now</tt>, and your object will
# vanish when the current action is done.
#
# Entries set via <tt>now</tt> are accessed the same way as standard entries: <tt>flash['my-key']</tt>.
def now
FlashNow.new self
end
# Keeps either the entire current flash or a specific flash entry available for the next action:
#
# flash.keep # keeps the entire flash
# flash.keep(:notice) # keeps only the "notice" entry, the rest of the flash is discarded
def keep(k=nil)
use(k, false)
end
# Marks the entire flash or a single flash entry to be discarded by the end of the current action
#
# flash.keep # keep entire flash available for the next action
# flash.discard(:warning) # discard the "warning" entry (it'll still be available for the current action)
def discard(k=nil)
use(k)
end
# Mark for removal entries that were kept, and delete unkept ones.
#
# This method is called automatically by filters, so you generally don't need to care about it.
def sweep #:nodoc:
keys.each do |k|
unless @used[k]
use(k)
else
delete(k)
@used.delete(k)
end
end
(@used.keys - keys).each{|k| @used.delete k } # clean up after keys that could have been left over by calling reject! or shift on the flash
end
private
# Used internally by the <tt>keep</tt> and <tt>discard</tt> methods
# use() # marks the entire flash as used
# use('msg') # marks the "msg" entry as used
# use(nil, false) # marks the entire flash as unused (keeps it around for one more action)
# use('msg', false) # marks the "msg" entry as unused (keeps it around for one more action)
def use(k=nil, v=true)
unless k.nil?
@used[k] = v
else
keys.each{|key| use key, v }
end
end
end
module InstanceMethods #:nodoc:
def assign_shortcuts_with_flash(request, response) #:nodoc:
assign_shortcuts_without_flash(request, response)
flash(:refresh)
end
def process_cleanup_with_flash
flash.sweep if @session
process_cleanup_without_flash
end
def reset_session_with_flash
reset_session_without_flash
remove_instance_variable(:@flash)
flash(:refresh)
end
protected
# Access the contents of the flash. Use <tt>flash["notice"]</tt> to read a notice you put there or
# <tt>flash["notice"] = "hello"</tt> to put a new one.
# Note that if sessions are disabled only flash.now will work.
def flash(refresh = false) #:doc:
if !defined?(@flash) || refresh
@flash =
if @session.is_a?(Hash)
# @session is a Hash, if sessions are disabled
# we don't put the flash in the session in this case
FlashHash.new
else
# otherwise, @session is a CGI::Session or a TestSession
# so make sure it gets retrieved from/saved to session storage after request processing
@session["flash"] ||= FlashHash.new
end
end
@flash
end
# deprecated. use <tt>flash.keep</tt> instead
def keep_flash #:doc:
warn 'keep_flash is deprecated; use flash.keep instead.'
flash.keep
end
end
end
end
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