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Diffstat (limited to 'actionpack/lib/action_controller/base/flash.rb')
| -rw-r--r-- | actionpack/lib/action_controller/base/flash.rb | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/actionpack/lib/action_controller/base/flash.rb b/actionpack/lib/action_controller/base/flash.rb new file mode 100644 index 0000000000..590f9be3ac --- /dev/null +++ b/actionpack/lib/action_controller/base/flash.rb @@ -0,0 +1,164 @@ +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 PostsController < ActionController::Base + # def create + # # save post + # flash[:notice] = "Successfully created post" + # redirect_to posts_path(@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] %> + # <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 + extend ActiveSupport::Concern + + include Session + + 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| keep(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.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) + 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 + + # clean up after keys that could have been left over by calling reject! or shift on the flash + (@used.keys - keys).each{ |k| @used.delete(k) } + end + + def store(session, key = "flash") + return if self.empty? + session[key] = self + 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) + # Returns the single value for the key you asked to be marked (un)used or the FlashHash itself + # if no key is passed. + def use(key = nil, used = true) + Array(key || keys).each { |k| @used[k] = used } + return key ? self[key] : self + end + end + + protected + def process_action(method_name) + super + if defined? @_flash + @_flash.store(session) + remove_instance_variable(:@_flash) + end + end + + def reset_session + super + remove_instance_variable(:@_flash) if defined?(@_flash) + end + + # 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. + def flash #:doc: + if !defined?(@_flash) + @_flash = session["flash"] || FlashHash.new + @_flash.sweep + end + + @_flash + end + end +end |