Pub/Sub on a particular topic?

[pselden]

I'm having trouble subscribing/publishing to a particular socket. Whatever I do, my subscriber ends up receiving all messages.

Is this not implemented?

// subscriber.js
var nano = require('nanomsg');

var sub = nano.socket('sub');
var nn = nano._bindings;

var addr = 'tcp://127.0.0.1:7789'
sub.setsockopt(nn.NN_SUB, nn.NN_SUB_SUBSCRIBE, 'my.topic');
sub.connect(addr);

sub.on('message', function (buf) {
    console.log(buf.toString());
});

// publisher.js
var nano = require('nanomsg');
var pub = nano.socket('pub');
var addr = 'tcp://127.0.0.1:7789'
pub.bind(addr);

setInterval(function () {
    pub.send("my.topic This is a topic");
    pub.send("my.dog My dog's name is Spot");
}, 1000);

[tcr]

@pselden Right now, this is hardcoded: https://github.com/nickdesaulniers/node-nanomsg/blob/master/src/node_nanomsg.cc#L31

We should instead be doing this from JavaScript: https://github.com/nickdesaulniers/node-nanomsg/blob/master/lib/index.js#L230

It would involve adding case NN_SUB_SUBSCRIBE: above this line: https://github.com/nickdesaulniers/node-nanomsg/blob/master/src/node_nanomsg.cc#L52

And calling setsockopt after a sub socket is created, probably: https://github.com/nickdesaulniers/node-nanomsg/blob/master/lib/index.js#L86

If you have time, we'd gladly accept a PR fixing this and running your test given case. :)

[mingfai]

+1 notice that people may use binary protocol so the filter/topic-prefix better support Buffer/ArrayBuffer

[asafyish]

+1

[nickdesaulniers]

I think this might actually be broken upstream. See #51 (comment)