Simple SSE (Server Sent Events) server in NodeJs

simple_sse_server.js

// 20 Feb 2023 - @todbot / Tod Kurt, for carlynorama
//
// orig from: https://web.dev/eventsource-basics/

var http = require('http');
var fs = require('fs');

var http_port =  8000

console.log("starting server on port"+http_port)

http.createServer(function(req, res) {
    if (req.headers.accept
        // && req.headers.accept == 'text/event-stream'
       ) {
        if (req.url == '/events') {
            sendSSE(req, res);
        } else {
            res.writeHead(404);
            res.end();
        }
    }
}).listen(http_port);

function sendSSE(req, res) {
    res.writeHead(200, {
        'Content-Type': 'text/event-stream',
        'Cache-Control': 'no-cache',
        'Connection': 'keep-alive'
    });

    // Sends a SSE every 2 seconds on a single connection.
    setInterval(function() {
        var id = (new Date()).toLocaleTimeString();
        var event_type = 'update'
        var data_str = '{"time":"'+ (new Date()).toLocaleTimeString() + '"}'
        constructSSE(res, id, event_type, data_str )
    }, 2000);
}

function constructSSE(res, id, event_type, data) {
    //res.write('id: ' + id + '\n');
    res.write('event: ' + event_type + '\n');
    res.write("data: " + data + '\n\n');
}