I think several things are being conflated here:

 1. Whether or not something is a node: Being a non-node simply
relates to how much infrastructure a single process starts up. The
difference in code is very little.
 2. Platform independence: rospy is platform independent, save for a
single line PYTHONPATH bootstrapper that doesn't work on Windows
(yet). It's very easy to override this.
 3. "Modest" segment of code: I would look at rospy or roslua. I get
the feeling that they are not as big as you think they are.

I think you'll find that, in implementing the steps you outline, you
will have implemented a nearly complete ROS client library, but by
being non ROS native, it will be more brittle and harder to maintain
in the long run. Similarly, by avoiding a ROS install, you'll jump
through extra hoops to get autogenerated service classes into your
codebase.

 - Ken


On Wed, Oct 6, 2010 at 7:30 AM, trinighost <trinighost@gmail.com> wrote:
>
> If I interpreted this sentence and the spirit of that section properly, the
> service client does not have to be a
> ROS node, and any code which could:
>
> 1) negotiate the XMLRPC handshaking (which seem to conform to some
> standard),
> 2) generate the proper connection header, and
> 3) send and decode serialized messages (over sockets and again apparently
> generated in "a" standard manner)
> ought to be able to communicate with a ROS based service provider.
>
> This should be an avenue available to code which doesn't call rospy or ROS
> native code.
> I'm interested in services which can communicate with ROS services but do
> not require a ROS install, or at least are dependent on a modest, platform
> independent segment of ROS code.
> Did I over simplify what I read?
> --
> View this message in context: http://ros-users.122217.n3.nabble.com/examples-of-non-ROS-service-clients-tp1636253p1642837.html
> Sent from the ROS-Users mailing list archive at Nabble.com.
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