Exemple using plugin-ws

plugin-ws.js

const pluginWs = require('@remixproject/plugin-ws')
const express = require('express')
const ws = require('express-ws')
const bodyParser = require('body-parser');
const cors = require('cors');

const app = express()
ws(app)

app.use(bodyParser.urlencoded({extended: true}))
app.use(bodyParser.json());
app.use(cors({origin: true}));
app.options('*', cors());

app.ws('/', async (socket) => {
  const client = pluginWs.createWebsocketClient(socket)
  await client.onload()
  await client.call('fileManager', 'setFile', 'browser/hello.txt', 'Hello World')
})

const port = 65520;
app.listen(port, () => console.log(`Remixd server started on port ${port}`));