Can a Node.js server accept incoming requests while the event queue is blocked?

Question

So I'm just starting to dive into Node and I understand that the I/O is non-blocking and that the event loop is blocking but what I am wondering is:

If you have code which is blocking the event queue, will the server still be able to place incoming requests at the end of the queue or will all of them just time out/bounce?

Answer 1

Yes. The server is still able to queue up requests. To demonstrate, I made the following file which blocks for 10 seconds, ran it, and curl'd the server on another terminal.

require('http').createServer(function(req, res) {
  console.log('got a request!');
  res.end('hello world!\n');
}).listen(3000);

var t = Date.now();
console.log('blocking..');
while(t + 10000 > Date.now());
console.log('not blocking anymore');

The result from running it

blocking..
not blocking anymore
got a request!