client.sh

#!/usr/bin/env bash

while :
do
    echo "Attempting to connect to $1:$2 ..."

    if exec 7<> /dev/tcp/$1/$2 ; then
        echo "Connection Established to $1:$2"

        while :
        do
            if read -u 7 TITLE && read -u 7 DESCRIPTION ; then
                notify-send "$TITLE" "$DESCRIPTION"
            else
                break
            fi
        done
    fi

    echo "Connection lost. Retrying in 5 seconds ..."
    sleep 5
done

server.js

const net = require("net");
const express = require("express");

const sockets = new Set();
const app = express().use(express.json());

app.post("/", (req, res) => {
    sockets.forEach((socket) => {
        socket.write(`${req.body.title}\n${req.body.description}\n`);
    });

    res.json({
        ...req.body,
        sentTo: sockets.size,
    });
});

const server = net.createServer((socket) => {
    sockets.add(socket);

    socket.on("close", () => {
        sockets.delete(socket);
    });
});

server.listen(9090, "0.0.0.0", () => {
    console.log(`Listen on 0.0.0.0:9090`);
});

app.listen(9091, "0.0.0.0", () => {
    console.log(`Server on http://0.0.0.0:9091`);
});