divide examples into two cases: with and without deserialisation

rosbag2_examples/rosbag2_examples_cpp/src/simple_bag_player.cpp

@@ -51,13 +51,20 @@ class SimpleBagPlayer : public rclcpp::Node
         continue;
       }
 
-      rclcpp::SerializedMessage serialized_msg(*msg->serialized_data);
-      std_msgs::msg::String::SharedPtr ros_msg = std::make_shared<std_msgs::msg::String>();
-
-      serialization_.deserialize_message(&serialized_msg, ros_msg.get());
-
-      publisher_->publish(*ros_msg);
-      std::cout << ros_msg->data << "\n";
+      if (message_needs_to_be_edit_before_send_)
+      {
+        rclcpp::SerializedMessage serialized_msg(*msg->serialized_data);
+        std_msgs::msg::String::SharedPtr ros_msg = std::make_shared<std_msgs::msg::String>();
+
+        serialization_.deserialize_message(&serialized_msg, ros_msg.get());
+        ros_msg->data += "[edited]";
+        publisher_->publish(*ros_msg);
+        std::cout << ros_msg->data << "\n";
+      }
+      else
+      {
+        publisher_->publish(*msg->serialized_data);
+      }
 
       break;
     }
@@ -68,6 +75,8 @@ class SimpleBagPlayer : public rclcpp::Node
 
   rclcpp::Serialization<std_msgs::msg::String> serialization_;
   rosbag2_cpp::Reader reader_;
+
+  bool message_needs_to_be_edit_before_send_ {true};
 };
 
 int main(int argc, char ** argv)

rosbag2_examples/rosbag2_examples_py/rosbag2_examples_py/simple_bag_player.py

@@ -34,15 +34,21 @@ def __init__(self, bag_filename):
         self.publisher = self.create_publisher(String, 'chatter', 10)
         # ignore timestamp and publish at a fixed rate (10 Hz).
         self.timer = self.create_timer(0.1, self.timer_callback)
+        self.message_needs_to_be_edit_before_send_ = True
 
     def timer_callback(self):
         while self.reader.has_next():
             msg = self.reader.read_next()
             if msg[0] != 'chatter':
                 continue
-            ros_msg = deserialize_message(msg[1], String)
-            self.publisher.publish(ros_msg)
-            self.get_logger().info(ros_msg.data)
+
+            if self.message_needs_to_be_edit_before_send_:
+                ros_msg = deserialize_message(msg[1], String)
+                ros_msg.data += '[edited]'
+                self.publisher.publish(ros_msg)
+                self.get_logger().info(ros_msg.data)
+            else:
+                self.publisher.publish(msg[1])
 
 
 def main(args=None):