toverux / expresse Goto Github PK

Let me start by pointing out a bug I found when applying your proposed to solution using this module with expressjs/compression.
You suggest that res.flush() be called after each res.sse.* call, but keep-alive messages also call the problematic res.write function, since this keep-alive logic happens outside of module user's reach we can't call flush after this happens.
This results in the client never receiving heartbeats until connection is closed or at user-level res.sse.* ; res.flush(); is called.

Secondly, what exactly are keep-alive messages for in this module?
Initially I thought they were a mechanism to be aware of a lost connection to a user, but there is no logic in place to notify module users of this.
So really what are they for?

I'm not able to receive events in the browser.

SERVER
res.sse.event("firstPaint", "10"); //

CLIENT

           `var source = new EventSource('/api/v1/get_SEE/test');

            source.addEventListener('message', function(e) {
                console.log("message"); //  never fired
            }, false);

            source.addEventListener('open', function(e) {
                // this is fired correctly when the page is opened
                console.log("connection opened");
            }, false);

            source.addEventListener('error', function(e) {
                if (e.readyState == EventSource.CLOSED) {
                    // this is fired correctly in the case
                    console.log("connection closed");
                }
            }, false);`

I am using vite-express and having this issue when making a GET request from my frontend to the route:

      res.sse.data('ok', someEvent)
                ^
TypeError: Cannot read properties of undefined (reading 'data')

I have used Typescript import:

import { ISseResponse, sse } from '@toverux/expresse'
let someEvent = 'foo'
router.get('/check', sse({ flushAfterWrite: true }) ,(res: ISseResponse) => {

    setTimeout(() => {
        res.sse.data('ok', someEvent)

    }, 1000)

})

I've been trying to make example code work for the past couple of hours .but couldn't make it work .I dont have much experience with node js .If possible can you provide some more like noob friendly example code .
I'm stuck at
someModule.on('someEvent', (event) => {

Does this someModule needs to be an event emitter ?

hope you reply to this

I'm using the simple form

    this.router.get('/:id/events', sse(), (req,res:ISseResponse) => { 
           someModule.on('someEvent', (event) => 

And what happens is that when I reload my client page a couple of times, the number of event listeners keep adding up (from the someModule.on).

I can't depend on clients properly calling some "unregister" url, so I'm wondering if there's any way to detect clients which are no longer listening for SSE?

Hi,

I want to use sseHub() with a different hub instance depending on the data in the request. Basically there are distinct sessions based on a token provided by the client, and each session should have its own hub. Since sseHub accepts ISseHubMiddlewareOptions that means I have to hard-code the hub, right? Is there any way to make it dynamic?

Basically, for each call of the API with the sseHub middleware, I need to first examine the request body to determine which hub to use for that client going forward.

I feel like I am going to end up subclassing Hub but I'm not sure of the direction, yet.

As stated in the documentation SSE encounters problem when undergoing compression. The proposed flushAfterWrite: true is not effective for webpack-dev-server compression (which is used in create-react-app). To resolve this, one can set the 'Cache-Control' response header to 'no-cache, no-transform' (at least while not in production). I wasn't sure how to alter response headers using expresse, so I uninstalled.

On the browser:

We can see that it connected successfully (the first event), but I can't get it to send events afterwards?

I'm setting up the hub and middleware in an exclusive file. Which it works because it prints to the console only once.

import { Hub, sseHub } from '@toverux/expresse';

export const hub = (() => {
  const hubInstance = new Hub();
  console.log('INFO - SSE Hub created');
  return hubInstance;
})();

export const hubMiddleware = sseHub({ hub, serializer: String });

Here's the router definition, which it works because we can access the endpoint as the screenshot above.

import hub from './sseHub';

server.get('/v1/companies/events', sseHub({ hub }), (req, res) => {
    res.sse.event('subscribed:company', Date.now());
  });

Here's another file where I subscribe to a Redis channel and want to transmit the data through the hub to others peers connected.

The console.log after the hub.event prints into the console right, so I'm not sure where I'm getting things wrong.

import { hub } from './sseHub';

export default function () {
  const { port, host, db } = configRedis;
  const client = redis.createClient({ host, port, db });

  client.on('pmessage', (pattern, channel, message) => {
    if (channel.includes('company:new:')) {
      hub.event('eventname', { data: message }); // tried hub.event('eventname', 'event') too
      console.log(`INFO - Nova Empresa (${channel.slice(-14)}) | TxID: ${message}`);
    }
  });

  client.psubscribe('company:new:*');
}