Why can my azure PubSub subscriber not recieve from my publisher - azure

Question

I am seeking to use groups within Azure PubSub, but it appears that either my publisher and subscriber are not both joining the same group somehow, or my serverless functions are not handling the broadcast after the message gets published. The service works if I publish without the groups implemented, but once I attempted to add groups I can see messages hitting the live trace tool on azure, but no messages being sent out after, so I suspect I may be missing something in my azure functions, but am not sure what that would be.
Publisher code:
const hub = "simplechat";
let service = new WebPubSubServiceClient("Endpoint=endpointURL", hub);
// by default it uses `application/json`, specify contentType as `text/plain` if you want plain-text
const group = service.group("myGroup");
group.sendToAll('Hello World', { contentType: "text/plain" });
Subscriber code:
const WebSocket = require('ws');
const { WebPubSubServiceClient } = require('#azure/web-pubsub');
var printer = require("printer/lib");
var util = require('util');
async function main() {
const hub = "simplechat";
let service = new WebPubSubServiceClient("EndpointEndpointURL", hub);
const group = service.group("myGroup");
let token = await service.getClientAccessToken();
let ws = new WebSocket(token.url, 'json.webpubsub.azure.v1');
ws.on('open', () => console.log('connected'));
ws.on('message', data => {
console.log('Message received: %s', data);
});
}
main();

Answer 1

I think you missed the part of joining your subscriber to the group.
The simplest way is to give the connection a user name and call addUser to add the connection to the group when the connection is connected:
async function main() {
const hub = "simplechat";
let service = new WebPubSubServiceClient("EndpointEndpointURL", hub);
const group = service.group("myGroup");
let token = await service.getClientAccessToken({ userId: "user1"});
// with this approach, the WebSocket actually does not need to be 'json.webpubsub.azure.v1' subprotocol, a simple WebSocket connection also works
let ws = new WebSocket(token.url, 'json.webpubsub.azure.v1');
ws.on('open', () => {
console.log('connected');
group.addUser("user1");
}
);
ws.on('message', data => {
console.log('Message received: %s', data);
});
}
Or you can wait until received the Connected Response to get the connectionId of the connection and call addConnection to add the subscriber to the group.
Another way, since you are already using json.webpubsub.azure.v1 protocol, would be that your subscriber to send the joinGroup request:
async function main() {
const hub = "simplechat";
let service = new WebPubSubServiceClient("EndpointEndpointURL", hub);
// make sure you set the joinLeaveGroup role for the group
let token = await service.getClientAccessToken({
roles: ['webpubsub.joinLeaveGroup.myGroup']
});
let ws = new WebSocket(token.url, 'json.webpubsub.azure.v1');
let ackId = 0;
ws.on('open', () => {
console.log('connected');
ws.send(JSON.stringify({
type: 'joinGroup',
group: 'myGroup',
ackId: ++ackId,
}));
});
ws.on('message', data => {
console.log('Message received: %s', data);
});
}
When your subscriber receives the AckMessage for this joinGroup action, your subscriber successfully joins the group.