How to handle Node.js http server timeout event? - node.js

Question

I have a HTTP server that will always result in HTTP timeout, e.g.
const server = http.createServer((req, res) => {
setTimeout(() => {
res.writeHead(200);
res.write('OK');
res.end();
}, 2000);
});
server.setTimeout(1000);
server.on('timeout', (socket) => {
// How to produce a custom HTTP response here?
});
HTTP server "timeout" event is emitted with socket reference. How do I use socket to encode HTTP response?
I know that I can stitch the response myself at a low-level, e.g.
server.on('timeout', (socket) => {
socket.write([
'HTTP/1.1 408 Request Timeout',
'Connection: close'
].join('\n') + '\n\n');
socket.end();
});
But is there a way to use the HTTP response interface, i.e. writeHead/ write/ end?

Answer 1

You could use the setTimeout function on the response object. Consider this simple example:
const http = require('http');
const port = 3000;
const requestHandler = (req, res) => {
res.setTimeout(Math.random() * 2500, () => {
res.writeHead(408);
res.end();
});
setTimeout(() => {
if (res.headersSent) {
return;
}
res.writeHead(200);
res.write('OK');
res.end();
}, 2000);
};
const server = http.createServer(requestHandler);
server.listen(port, (err) => {
if (err) {
return console.log('an error happened', err)
}
console.log(`server is listening on ${port}`)
});
If you call localhost:3000 in your web browser you'll now either see 200 OK or a 408 error. Note that you'll need to handle already sent headers if the random timeout was less than 2000 ms.