message.rb in messaging-3.5.5

- old
+ new

@@ -23,10 +23,36 @@
       attribute :timestamp,     Time,   default: ->(*) { Time.current.utc }
       attribute :uuid,          String, default: ->(*) { SecureRandom.uuid }
     end
 
     module ClassMethods
+      # The stream that the message will be stored in when published.
+      #
+      # Stream names consists of the stream category and the stream id separated by a $.
+      # For instance "customer$123" where "customer" is the category and "123" is the id.
+      #
+      # When no stream name is given the message will not be persisted in the message store.
+      #
+      # @param [#call,String,nil] name The name of the stream, will be evaluated in the context
+      #   of the message instance.
+      #
+      # @example
+      #   class CustomerRegistered
+      #     include Messaging::Message
+      #
+      #     stream_name -> { "customer$#{customer_id}"}
+      #
+      #     attribute :customer_id, Integer
+      #    end
+      #
+      #    CustomerRegistered.new(customer_id: 123).stream_name
+      #    # => "customer$123"
+      def stream_name(name = nil)
+        return @stream_name unless name
+        @stream_name = name
+      end
+
       # By default the topic is the same as the name of the message.
       # We change the / that would be set for a namespaced message as "/" isn't valid in a topic
       # To change the topic for a message just set it to whatever you want in your class definition.
       def topic(topic_name = nil)
         @topic ||= topic_name&.to_s || default_topic_name
@@ -86,11 +112,11 @@
     def topic
       self.class.topic
     end
 
     def stream_name
-      # define stream_name in your message class to override
-      nil
+      return unless self.class.stream_name
+      instance_exec(&self.class.stream_name)
     end
 
     def stream_category
       return unless stream_name
 