require 'active_support/core_ext/hash/keys' module ActionDispatch class Request < Rack::Request # 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 @env[Flash::KEY] ||= Flash::FlashHash.from_session_value(session["flash"]) end end # The flash provides a way to pass temporary primitive-types (String, Array, Hash) 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] = "Post successfully created" before redirecting to a display action that can # then expose the flash to its template. Actually, that exposure is automatically done. # # class PostsController < ActionController::Base # def create # # save post # flash[:notice] = "Post successfully created" # redirect_to @post # end # # def show # # doesn't need to assign the flash notice to the template, that's done automatically # end # end # # show.html.erb # <% if flash[:notice] %> #
<%= flash[:notice] %>
# <% end %> # # Since the +notice+ and +alert+ keys are a common idiom, convenience accessors are available: # # flash.alert = "You must be logged in" # flash.notice = "Post successfully created" # # This example places a string in the flash. And of course, you can put as many as you like at a time too. If you want to pass # non-primitive types, you will have to handle that in your application. Example: To show messages with links, you will have to # use sanitize helper. # # 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. class Flash KEY = 'action_dispatch.request.flash_hash'.freeze class FlashNow #:nodoc: attr_accessor :flash def initialize(flash) @flash = flash end def []=(k, v) k = k.to_s @flash[k] = v @flash.discard(k) v end def [](k) @flash[k.to_s] end # Convenience accessor for flash.now[:alert]=. def alert=(message) self[:alert] = message end # Convenience accessor for flash.now[:notice]=. def notice=(message) self[:notice] = message end end class FlashHash include Enumerable def self.from_session_value(value) flash = case value when FlashHash # Rails 3.1, 3.2 new(value.instance_variable_get(:@flashes), value.instance_variable_get(:@used)) when Hash # Rails 4.0 new(value['flashes'], value['discard']) else new end flash.tap(&:sweep) end def to_session_value return nil if empty? {'discard' => @discard.to_a, 'flashes' => @flashes} end def initialize(flashes = {}, discard = []) #:nodoc: @discard = Set.new(stringify_array(discard)) @flashes = flashes.stringify_keys @now = nil end def initialize_copy(other) if other.now_is_loaded? @now = other.now.dup @now.flash = self end super end def []=(k, v) k = k.to_s @discard.delete k @flashes[k] = v end def [](k) @flashes[k.to_s] end def update(h) #:nodoc: @discard.subtract stringify_array(h.keys) @flashes.update h.stringify_keys self end def keys @flashes.keys end def key?(name) @flashes.key? name.to_s end def delete(key) key = key.to_s @discard.delete key @flashes.delete key self end def to_hash @flashes.dup end def empty? @flashes.empty? end def clear @discard.clear @flashes.clear end def each(&block) @flashes.each(&block) end alias :merge! :update def replace(h) #:nodoc: @discard.clear @flashes.replace h.stringify_keys self 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']. # # Also, brings two convenience accessors: # # flash.now.alert = "Beware now!" # # Equivalent to flash.now[:alert] = "Beware now!" # # flash.now.notice = "Good luck now!" # # Equivalent to flash.now[:notice] = "Good luck now!" def now @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) k = k.to_s if k @discard.subtract Array(k || keys) k ? self[k] : self end # Marks the entire flash or a single flash entry to be discarded by the end of the current action: # # flash.discard # discard the entire flash at the end of the current action # flash.discard(:warning) # discard only the "warning" entry at the end of the current action def discard(k = nil) k = k.to_s if k @discard.merge Array(k || keys) k ? self[k] : self 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: @discard.each { |k| @flashes.delete k } @discard.replace @flashes.keys end # Convenience accessor for flash[:alert]. def alert self[:alert] end # Convenience accessor for flash[:alert]=. def alert=(message) self[:alert] = message end # Convenience accessor for flash[:notice]. def notice self[:notice] end # Convenience accessor for flash[:notice]=. def notice=(message) self[:notice] = message end protected def now_is_loaded? @now end def stringify_array(array) array.map do |item| item.kind_of?(Symbol) ? item.to_s : item end end end def initialize(app) @app = app end 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 end end