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 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.rhtml # <% if @flash[:notice] %>
<%= @flash[:notice] %>
<% 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.append_features(base) #:nodoc: super base.before_filter(:fire_flash) base.after_filter(:sweep_flash) 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 @@avoid_sweep = false cattr_accessor :avoid_sweep 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 ([]=). # When you need to pass an object to the current action, you use now, and your object will # vanish when the current action is done. # # Entries set via now are accessed the same way as standard entries: flash['my-key']. 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: return if @@avoid_sweep 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 keep and discard 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 protected # Access the contents of the flash. Use flash["notice"] to read a notice you put there or # flash["notice"] = "hello" to put a new one. def flash #:doc: @session['flash'] ||= FlashHash.new end # deprecated. use flash.keep instead def keep_flash #:doc: flash.keep end private # marks flash entries as used and expose the flash to the view def fire_flash flash.discard @assigns["flash"] = flash end # deletes the flash entries that were not marked for keeping def sweep_flash flash.sweep end end end