Publish to multiple subscribers

[baalexander]

Need to investigate if a publisher can publish to more than one subscriber.

A subscriber sends a requestTopic call to the publisher, which it does handle correctly for one subscriber. But if multiple subscribers call, does it keep track of each? Topic may need to have an array of protocols instead of a single protocol.

[baalexander]

Thanks for taking a look into this @maxired.

If you see a better way for communicating between node.js, topic.js, and tcpros.js while working on the issue, please let me know. I think it's a tad confusing right now.

[baalexander]

I included your commits in my API update to master. I did this because otherwise you would have merge conflicts since I got rid of node.js and changed up topic.js.

That said, I had to comment out most your multiple socket code because it wasn't working for me. I kept most of it in there, just commented out. Sorry for the change midway during your change, but hopefully my commit made the code a little easier to manage and work with.

[maxired]

Hi,

It appears that I can't fix this without changing the way the publish method works. (publish only to currently connected subscribers)

https://github.com/baalexander/rosnodejs/commit/6839c1dfcd5b690a4d813ea96b120946da8250f3#L5L28#L5L32 seems to show that you don't really want my proposal, so I don't know exactly what to do.

[baalexander]

@maxired - You can change the implementation of publish().

However, I'd still prefer being able to call topic.publish() directly like so:

var publisher = new ros.topic({
  node        : 'talker'
, topic       : 'publish_example'
, messageType : String
});

var message = new String({ data: 'howdy' });
publisher.publish(message);

Will that work? Or does calling publish() directly like mentioned above create a problem?

[maxired]

@baalexander : It will be easy if you are Okay with the fact that only currently connected nodes will receive the message.

[baalexander]

That works for me for me for now. I'll have better thoughts on supporting unconnected nodes after your pull request.

[baalexander]

I merged the fixes for this into master. Please let me know if it didn't work in your testing.

I'll update the npm version to 0.1.2 tomorrow if everything looks good.

[maxired]

Hi, I'll try today and let you know