1 files changed, 79 insertions, 0 deletions
diff --git a/actioncable/lib/action_cable/channel/periodic_timers.rb b/actioncable/lib/action_cable/channel/periodic_timers.rb
new file mode 100644
index 0000000000..dab604440f
--- /dev/null
+++ b/actioncable/lib/action_cable/channel/periodic_timers.rb
@@ -0,0 +1,79 @@
+module ActionCable
+  module Channel
+    module PeriodicTimers
+      extend ActiveSupport::Concern
+
+      included do
+        class_attribute :periodic_timers, instance_reader: false
+        self.periodic_timers = []
+
+        after_subscribe   :start_periodic_timers
+        after_unsubscribe :stop_periodic_timers
+      end
+
+      module ClassMethods
+        # Periodically performs a task on the channel, like updating an online
+        # user counter, polling a backend for new status messages, sending
+        # regular "heartbeat" messages, or doing some internal work and giving
+        # progress updates.
+        #
+        # Pass a method name or lambda argument or provide a block to call.
+        # Specify the calling period in seconds using the <tt>every:</tt>
+        # keyword argument.
+        #
+        #     periodically :transmit_progress, every: 5.seconds
+        #
+        #     periodically every: 3.minutes do
+        #       transmit action: :update_count, count: current_count
+        #     end
+        #
+        def periodically(callback_or_method_name = nil, every:, &block)
+          callback =
+            if block_given?
+              raise ArgumentError, 'Pass a block or provide a callback arg, not both' if callback_or_method_name
+              block
+            else
+              case callback_or_method_name
+              when Proc
+                callback_or_method_name
+              when Symbol
+                -> { __send__ callback_or_method_name }
+              else
+                raise ArgumentError, "Expected a Symbol method name or a Proc, got #{callback_or_method_name.inspect}"
+              end
+            end
+
+          unless every.kind_of?(Numeric) && every > 0
+            raise ArgumentError, "Expected every: to be a positive number of seconds, got #{every.inspect}"
+          end
+
+          self.periodic_timers += [[ callback, every: every ]]
+        end
+      end
+
+      private
+        def active_periodic_timers
+          @active_periodic_timers ||= []
+        end
+
+        def start_periodic_timers
+          self.class.periodic_timers.each do |callback, options|
+            active_periodic_timers << start_periodic_timer(callback, every: options.fetch(:every))
+          end
+        end
+
+        def start_periodic_timer(callback, every:)
+          connection.server.event_loop.timer every do
+            connection.worker_pool.async_invoke connection do
+              instance_exec(&callback)
+            end
+          end
+        end
+
+        def stop_periodic_timers
+          active_periodic_timers.each { |timer| timer.shutdown }
+          active_periodic_timers.clear
+        end
+    end
+  end
+end