[question] Creating a websocket server using Typescript

[briant-spindance]

I'm trying to make a create a websocket server in Typescript, and I can't seem to translate the Javascript examples I've found into Typescript.

Here's what I have so far:

import { Server } from "aedes";
import * as http from "http";
import * as ws from "websocket-stream";

const broker = Server();
const httpServer = http.createServer();
ws.createServer({ server: httpServer }, broker.handle);

I'm getting an error:

"Argument of type '(stream: Connection) => Client' is not assignable to parameter of type '() => void'."

Any pointers on where I'm going wrong?

[robertsLando]

The problem is in websocket-stream module interface: https://github.com/maxogden/websocket-stream/blob/master/index.d.ts#L21

That type mismatch with the one on Aedes.d.ts

However you can also use another way:

const { createWebSocketStream, Server } = require('ws')

function createWebsocketServer (server, broker) {
  const ws = new Server({ server })

  ws.on('connection', function (conn, req) {
    var stream = createWebSocketStream(conn)
    broker.handle(stream)
  })
}

const http = require('http')
const server = http.createServer()
// Than use this function to bind aedes to your server
createWebsocketServer(server, broker)

[briant-spindance]

Sorry, looks like I +1 too quick!

 stream._socket = conn._socket

throws an error, and it looks like broker.handle only accepts one param.

BTW, if we can get this sorted out, I'd be happy to open a PR for some better Typescript examples.

[robertsLando]

@briant-spindance Try with my updated comment now and let me know if it works

[briant-spindance]

@robertsLando That worked! Thanks for the help.

[joseAveleira]

Sorry, I have a similar problem, I'm trying to make a project in typescript with MQTT, express and websockets functionality but I don't know how to implement the solution mentioned in the previous comment

import express from "express";
import { Server, Client, AuthenticateError } from "aedes";
import { createServer, Socket } from "net";
import * as http from "http";
//import * as ws from "websocket-stream"  //problem "Argument of type '(stream: Connection) => Client' is not assignable to parameter of type '() => void'."
var ws = require("websocket-stream"); 

const broker = Server({
  heartbeatInterval: 60000,
});

broker.on("publish", (packet, client) => {
  if (client) {
    console.log("%s : topic %s : %s", client.id, packet.topic, packet.payload);
  }
});

// Initializations
const app = express();

// Settings
app.set("port", process.env.PORT || 3000);

//ws server

/* Problem  createWebSocketStream is not a function
import { createWebSocketStream, Server } from 'ws';
const serverws = http.createServer();

const ws = new Server({server:serverws, port:2000})
ws.on('connection', function (conn, req) {
  var stream = createWebSocketStream(conn)
  broker.handle(stream)
})
*/

var wsServer = http.createServer();
ws.createServer({ server: wsServer }, broker.handle);
wsServer.listen(2000, function () {
  console.log("functional WS");
});

// MQTT server
const server = createServer(broker.handle);
server.listen(1883);

//test Express
app.get("/", function (req, res) {
  res.send("Hello Worlds!");
});

//Express server
app.listen(app.get("port"), () => {
  console.log(`server on port ${app.get("port")}`);
});

`

[robertsLando]

npm install --save ws ?

[joseAveleira]

Yes, thank you, it was a bit frustrating, I installed WS and it didn't fail to find the module, but when I reinstalled it, it was fixed

Thank you very much, I'll keep working