Make frontend fields stateless to resolve repeating content issues.

This eliminates the concept of a store for timeline data, which was just
going to the client anyway when cookie store was enabled. Instead, the
entire timeline worth of content will be sent to the client. This
timeline is not reliant on getting a cookie back which could have been
overwritten in the client by a simultaneous request.

If a reliable store for this data is found, the store concept could be
reinstated. However the only reason for this would seem to be if the
client could not store the whole timeline, which seems unlikely.

See #1329.

app/controllers/frontend/contents_controller.rb

@@ -22,19 +22,14 @@ def index
 
     shuffle_config = FieldConfig.get(@screen, @field, 'shuffler') || DEFAULT_SHUFFLE
     shuffler_klass = FrontendContentOrder.load_shuffler(shuffle_config)
-    session_key = "frontend_#{@screen.id}_#{@screen.template.id}_#{@field.id}_#{shuffler_klass}".to_sym
     shuffler = nil
-    count = 1
-
-    count = 20 if FieldConfig.get(@screen, @field, 'marquee') == '1'
 
     run_callbacks :index do # Run plugin hooks
-      shuffler = shuffler_klass.new(@screen, @field, @subscriptions, session[session_key])
-      @content = shuffler.next_contents(count)
+      shuffler = shuffler_klass.new(@screen, @field, @subscriptions)
+      @content = shuffler.next_contents()
     end
 
     auth! object: @content
-    session[session_key] = shuffler.save_session()
 
     begin
       @content.each do |c|

lib/base_shuffle.rb

@@ -7,40 +7,19 @@ class BaseShuffle
   # @param [Screen] screen Screen showing the content.
   # @param [Field] field Field showing the content.
   # @param [Array<Subscription>] subscriptions All the subscriptions to use.
-  # @param [Array<Integer>] store Array to store a timeline if needed.
   # @param [Hash] options Any additional options. 
-  def initialize(screen, field, subscriptions, store=[], options={})
+  def initialize(screen, field, subscriptions, options={})
     @screen = screen
     @field = field
     @subscriptions = subscriptions
-    @store = store
     @options = options
-
-    @store = [] if @store.nil?
   end
 
   # Return the next set content to be shown.
   #
-  # @param [Integer] count Number of content needed, defaults to 1.
   # @return [Array<Content>] Next content that should be rendered.
-  def next_contents(count=1)
-    if @store.length < count
-      content = content()
-      @store += content.collect{|c| c.id}
-    end
-    return [] if @store.empty?
-
-    content_ids = @store.shift(count)
-    Content.where(id: content_ids).to_a.compact
-  end
-
-  # Return a timeline to be saved.
-  # Since we can't directly access the session, the controller
-  # will pull here for what should be saved.
-  #
-  # @return [Array<Integer>] Array of content ids in the timeline.
-  def save_session()
-    @store
+  def next_contents()
+    content.to_a.compact
   end
 
   private

lib/weighted_shuffle.rb

@@ -6,15 +6,8 @@
 # then jumbled up and served from a timeline.
 class WeightedShuffle < BaseShuffle
 
-  def next_contents(count=1)
-    if @store.length < count
-      content = weighted_content()
-      @store += content.collect{|c| c.id}
-    end
-    return [] if @store.empty?
-
-    content_ids = @store.shift(count)
-    Content.where(id: content_ids).to_a.compact
+  def next_contents()
+    weighted_content.to_a.compact
   end
 
   private