Support for Parameters?

[McModknower]

Is there support for ros1 parameters in this crate?
If not, is it planned, should i create and issue for it, or should i try implementing it myself?

[Carter12s]

Hey great question! We do have (somewhat hacky) support for parameters via the roslibrust_rosapi crate which is in the source code: https://github.com/RosLibRust/roslibrust/tree/master/roslibrust_rosapi, but we haven't published as a standalone crate. That implementation relies on a running rosapi node, and simply makes service calls to the rosapi node to accomplish various things.

A nice thing about that approach is that it can work with any of the backends as long as a rosapi node is running, and there is even a rosapi node for ROS2. There are a couple of possible paths to get from our current state to a working and well documented state:

1. Finish / fix the rosapi crate, and set it up behind a feature flag on the main roslibrust crate. This could provide parameter support to all backends, but requires the rosapi node to be running...
   1. We need to figure out how we want message generation of the rosapi message types to work? Probably, generate them at compile time with build.rs script or roll hand written message.
   2. We likely want to clean-up the rosapi trait around parameters to automatically include serialziation and deserialization.
   3. Documentation and examples
2. Abandon the current rosapi start, and start fresh on Parameter specific traits / implementations.
   1. Define a new trait "ParameterServer" (not sure if best name?)
   2. Impl ParameterServer for ROS1 backend using the xmlrpc API
   3. Impl ParameterServer for Zenoh backend using whatever shenanigans zenoh-bridge-ros1 is doing
   4. Impl ParameterServer for rosbridge backend using the rosapi node (only choice)
   5. Documentation and examples

To answer your question more clearly:

• We would love to support parameters, been on the list of things to support for a while, but you're actually the first person to directly ask for it.
• Creating an issue for it would be great!
• I'd love for you to take a stab at implementing and would be happy to help get you started, provide some guidance, and review along the way.