blocks|key|79949|text|您的代码可以接受多个连接，因为作业是在setTimeout调用的回调函数中完成的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|79950|但是如果你代替setTimeout做一件繁重的工作..。那么，node.js将不会接受其他多个连接是真的！SetTimeout意外地释放了进程，因此node.js可以接受其他作业，您的代码将在其他“线程”中执行。|79951|我不知道哪种方式才是正确的实现方式。但这似乎就是它的工作方式。|79952|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

Your code can accept multiple connections because the job is done in callback function of the setTimeout call. 

But if you instead of setTimeout do a heavy job... then it is true that node.js will not accept other multiple connections! SetTimeout accidentally frees the process so the node.js can accept other jobs and you code is executed in other "thread". 

I don't know which is the correct way to implement this. But this is how it seems to work.

blocks|key|80028|text|我使用了以下代码来测试请求处理|type|unstyled|depth|inlineStyleRanges|entityRanges|data|80029|app.get('/',+function(req,+res)+{
++console.log('time',+MOMENT());++
++setTimeout(+function()+{
++++console.log(data,+'++++++++++',+MOMENT());
++++res.send(data);
++++data+=+'changing';
++},+50000);
++var+data+=+'change+first';
++console.log(data);
});|code-block|syntax|javascript|80030|因为这个请求不需要那么多的处理时间，除了50秒的setTimeout和所有的超时都像往常一样一起处理。|80031|一起响应3个请求-|80032|time+moment("2017-05-22T16:47:28.893")
change+first
time+moment("2017-05-22T16:47:30.981")
change+first
time+moment("2017-05-22T16:47:33.463")
change+first
change+first++++++++++++moment("2017-05-22T16:48:18.923")
change+first++++++++++++moment("2017-05-22T16:48:20.988")
change+first++++++++++++moment("2017-05-22T16:48:23.466")|80033|在此之后，我进入了第二阶段...也就是说，如果我的请求花了这么多时间来处理同步文件或其他需要时间的事情，那该怎么办？|80034|app.get('/second',+function(req,+res)+{
++++console.log(data);
++++if(req.headers.data+===+'9')+{
++++++++res.status(200);
++++++++res.send('response+from+api');
++++}+else+{
++++++++console.log(MOMENT());
++++++++for(i+=+0;+i<9999999999;+i%2B%2B){}
++++++++console.log('Second+MOMENT',+MOMENT());
++++++++res.status(400);
++++++++res.send('wrong+data');
++++}

++++var+data+=+'second+test';
});|80035|由于我的第一个请求仍在处理中，因此Node没有接受我的第二个请求。因此，我得到了以下2个请求的响应-|80036|undefined
moment("2017-05-22T17:43:59.159")
Second+MOMENT+moment("2017-05-22T17:44:40.609")
undefined
moment("2017-05-22T17:44:40.614")
Second+MOMENT+moment("2017-05-22T17:45:24.643")+|80037|因此，对于所有异步功能，Node中都有一个虚拟线程，Node在完成之前的请求异步工作(如fs、mysql或调用API)之前接受其他请求，但它将自己保留为单线程，并在完成之前的所有请求之前不处理其他请求。|80038|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|10|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|14|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|15|8|@]|9|@]|A|$]]|$1|S|3|T|5|D|7|16|8|@]|9|@]|A|$E|F]]|$1|U|3|V|5|6|7|17|8|@]|9|@]|A|$]]|$1|W|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|X|$]]

I used following code to test request handling

<pre><code>app.get('/', function(req, res) {
 console.log('time', MOMENT()); 
 setTimeout( function() {
 console.log(data, ' ', MOMENT());
 res.send(data);
 data = 'changing';
 }, 50000);
 var data = 'change first';
 console.log(data);
});
</code></pre>

Since this request doesn't take that much processing time, except for 50 sec of setTimeout and all the time-out were processed together like usually do.

Response 3 request together-

<pre><code>time moment("2017-05-22T16:47:28.893")
change first
time moment("2017-05-22T16:47:30.981")
change first
time moment("2017-05-22T16:47:33.463")
change first
change first moment("2017-05-22T16:48:18.923")
change first moment("2017-05-22T16:48:20.988")
change first moment("2017-05-22T16:48:23.466")
</code></pre>

After this i moved to second phase... i.e., what if my request takes so much time to process a sync file or some thing else that take time.

<pre><code>app.get('/second', function(req, res) {
 console.log(data);
 if(req.headers.data === '9') {
 res.status(200);
 res.send('response from api');
 } else {
 console.log(MOMENT());
 for(i = 0; i&lt;9999999999; i++){}
 console.log('Second MOMENT', MOMENT());
 res.status(400);
 res.send('wrong data');
 }

 var data = 'second test';
});
</code></pre>

As my first request was still in process so my second didn't get accepted by Node. Thus i got following response of 2 request-

<pre><code>undefined
moment("2017-05-22T17:43:59.159")
Second MOMENT moment("2017-05-22T17:44:40.609")
undefined
moment("2017-05-22T17:44:40.614")
Second MOMENT moment("2017-05-22T17:45:24.643") 
</code></pre>

Thus For all Async functions theres a virtual thread in Node and Node does accept other request before completing previous requests async work like(fs, mysql,or calling API), however it keeps it self as single thread and does not process other request until all previous ones are completed.

blocks|key|297304|text|浏览器会阻止其他相同的请求。如果你从不同的浏览器调用它，那么它将并行工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|297305|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Browser blocks the other same requests. If you call it from different browsers then this will work parallelly.

I know that Node is non-blocking, but I just realized that the default behaviour of <code>http.listen(8000)</code> means that all HTTP requests are handled one-at-a-time. I know I shouldn't have been surprised at this (it's how ports work), but it does make me seriously wonder how to write my code so that I can handle multiple, parallel HTTP requests. 

So what's the best way to write a server so that it doesn't hog port 80 and long-running responses don't result in long request queues?

To illustrate the problem, try running the code below and loading it up in two browser tabs at the same time.

<pre><code>var http = require('http');
http.createServer(function (req, res) {
 res.setHeader('Content-Type', 'text/html; charset=utf-8');
 res.write("&lt;p&gt;" + new Date().toString() + ": starting response");
 setTimeout(function () {
 res.write("&lt;p&gt;" + new Date().toString() + ": completing response and closing connection&lt;/p&gt;");
 res.end();
 }, 4000);
}).listen(8080);
</code></pre>

Handling multiple parallel HTTP requests in Node.js

服务器

我知道Node是非阻塞的，但我刚刚意识到http.listen(8000)的默认行为意味着所有的HTTP请求都是一次处理一个。我知道我不应该对此感到惊讶(这就是端口的工作方式)，但它确实让我很想知道如何编写代码，以便能够处理多个并行的HTTP请求。那么，编写服务器的最好方法是什么，这样它就不会占用端口80，并且长时间运...

问在Node.js中处理多个并行HTTP请求
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