Node.JS-使用异步功能处理传入的请求

Question

As far as I understand Node.js is single threaded and handles each request one at a time. However, when making asynchronous calls it should be able to deal with new requests while the callbacks haven't been called yet.

So when I make 3 request simultaneously to the following server implementation, why does it wait for 10 sec for the first response, and then 20 for the 2nd, and 30 for the 3rd...?

var express = require('express');    
    var app = express();
    app.get('*', function(req, res) {
        setTimeout(function(){
            res.end('done')
        },10000)
    });
    app.listen(8000);

Answer 1

Instead of checking this using your browser, you should test it with another node.js script... For example, using this script:

var http = require('http');

function test(timestamp) {
    http.get('http://127.0.0.1:8000',function(res) {
           console.log(new Date() - timestamp);
    });
}


for (var i = 0 ; i < 5 ; i++) {
    test(new Date().getTime());
}

I get the following result (Using your code as http server):

> node test.js
10032
10029
10029
10029
10030

So it seems that the problem wasn't on you're node.js code.