I'm facing a situation where I have multiple robots, most running full ROS stacks (complete with Master) and I'd like to selectively route some topics through another messaging framework to the other robots (some of which not running ROS).
The naive way to do this works, namely, to set up a node that subscribes to the ROS topics in question and sends that over the network, after which another node publishes it (if its ROS). Great, but it seems odd to have to do this much serializing. Right now the message goes from its message type to the ROS serialization, back to the message type, then to a different serialization format (currently Pickle), across the network, then back to the message type, then back to the ROS serialization, then back to the message type.
So the question is, can I simplify this? How can I operate on the ROS serialized data (ie subscribe without rospy automagically deserializing for me)? http://wiki.ros.org/rospy/Overview/Publishers%20and%20Subscribers suggests that I can access the connection information as dict of strings, which may be half of the solution, but how can the other end take the connection information and republish it without first deserializing and then immediately reserializing?
Edit: I just found https://gist.github.com/wkentaro/2cd56593107c158e2e02 , which seems to solve half of this. It uses AnyMsg to avoid deserializing on the ROS subscriber side, but then when it republishes it still deserializes and immediately reserializes the message. Is what I'm asking impossible?
Just to close the loop on this, it turns out you can publish AnyMsgs, it's just that the linked examples chose not to.