Publish doesn't publish to current peer

[rijkvanzanten]

Environment

node@22.14.0

nuxt@4.0.3
  → h3@@1.15.4
    → crossws@0.3.5

Reproduction

Use peer.publish

Describe the bug

According to the documentation, peer.publish broadcasts a message to the subscribers of the given channel. However, I noticed that the peer that triggered the publish itself never received the message, even though it was subscribed to the channel.

Additional context

On closer look, it looks like this was implemented intentionally here:

crossws/src/adapters/node.ts

Line 179 in 84cf679

if (peer !== this && peer._topics.has(topic)) {

as it explicitly checks if the peer isn't the current peer before sending the message. Not entirely sure if this is a bug or a 'feature'; depending on that this is either a bug report or a request for better documentation. Happy to open a PR for either of those :)

Logs

[pi0]

This isn't a bug but expected behavior. We should improve documentation to clarify it.

We could also introduce a new option like peer.publish(topic, message, { self: true }) to enable echo-back behavior.

(PR welcome for both)

[rijkvanzanten]

expected behavior

intended* behavior 😁 My background in sockets is from socket.io back in the day which introduced the idea of broadcasting to rooms, but also set the standard that a broadcast to a room would send the message to all participants of this room. I therefore expected crossws' topic to behave similarly to that pre-established pattern 🙂

[rijkvanzanten]

@pi0 The code uses the nomenclature topic, but the documentation calls it channel. Any preference for one over the other? Lets make it consistent while we're at it 🙂

[rijkvanzanten]

Sorry for the spam, but had one more follow-up here. Does the self-exclusion in publishing work consistently across vendors at the moment? Noticed the peer !== this check in some adapters like node or SSE:

crossws/src/adapters/node.ts

Line 179 in 84cf679

if (peer !== this && peer._topics.has(topic)) {

crossws/src/adapters/sse.ts

Lines 147 to 154 in 84cf679

	publish(topic: string, data: unknown) {
	const dataBuff = toString(data);
	for (const peer of this._internal.peers) {
	if (peer !== this && peer._topics.has(topic)) {
	peer._sendEvent("message", dataBuff);
	}
	}
	}

but not others like bun:

crossws/src/adapters/bun.ts

Lines 127 to 131 in 84cf679

	return this._internal.ws.publish(
	topic,
	toBufferLike(data),
	options?.compress,
	);

[pi0]

Native behavior of Bun pub/sub publish is to publish to all excluding self (docs), and I think the same for some others, so if we want to introduce self: true, we need an additional logic for them to do self-publish.

Let's first fix up the docs, We should clarify the current behavior. Also nice find about topic/channel, i think topic might make sense because we currently have peer.topics.

Another note: Crossws also has a new global publish introduced in v0.4 (release notes) which is still not documented and not available in Nitro but we should document that too!