如何限制node.js中服务器的上传速度？ [英] How would I limit upload speed from the server in node.js?

问题描述

如何限制node.js服务器的上传速度？

这甚至是一个选项吗？

场景：我正在编写一些方法来允许用户自动将文件上传到我的服务器。我想限制上传速度（例如）50kB / s（当然配置）。

解决方案

我不认为您可以强制客户端以预定义的速度进行流式处理，但是您可以控制整个流程的平均速度。

  var startTime = Date.now（），
 totalBytes = ...，//注意：你需要客户端给你传入字节总数
 curBytes = 0; 
 
 stream.on（'data'，function（chunk）{//注意：chunk应该是一个缓冲区，如果字符串寻找不同的方法来获取写入的字节
 curBytes + = chunk.length; 
 var offsetTime = calcReqDelay（targetUploadSpeed）; 
 if（offsetTime> 0）{
 stream.pause（）; 
 setTimeout（offsetTime，stream.resume） ; 
} 
}）; 
 
函数calcReqDelay（targetUploadSpeed）{//速度以字节为单位
 var timePassed = Date.now（） -  startTime; 
 var targetBytes = targetUploadSpeed * timePassed / 1000; 
 //计算需要等待多久（返回减去以防我们实际上应该更快）
 return waitTime; 
 
 
 
 $ b $ p 
 $ b 
这当然是伪代码，但你可能会明白这一点。可能有另外一种更好的方式，我不知道。在这种情况下，我希望别人会指出。
 
 
 
请注意，它也不是很精确，你可能想要有一个不同的指标比平均速度。
 
How would I limit upload speed from the server in node.js?

Is this even an option?

Scenario: I'm writing some methods to allow users to automated-ly upload files to my server. I want to limit the upload speed to (for instance) 50kB/s (configurable of course).
解决方案
I do not think you can force a client to stream at a predefined speed, however you can control the "average speed" of the entire process.
var startTime  = Date.now(),
    totalBytes = ..., //NOTE: you need the client to give you the total amount of incoming bytes
    curBytes   = 0;

stream.on('data', function(chunk) { //NOTE: chunk is expected to be a buffer, if string look for different ways to get bytes written
     curBytes += chunk.length;
     var offsetTime = calcReqDelay(targetUploadSpeed);
     if (offsetTime > 0) {
         stream.pause();
         setTimeout(offsetTime, stream.resume);
     }
});

function calcReqDelay(targetUploadSpeed) { //speed in bytes per second
    var timePassed = Date.now() - startTime;
    var targetBytes = targetUploadSpeed * timePassed / 1000;
    //calculate how long to wait (return minus in case we actually should be faster)
    return waitTime;
}
This is of course pseudo code, but you probably get the point. There may be another, and better, way which I do not know about. In such case, I hope someone else will point it out.

Note that it is also not very precise, and you may want to have a different metric than the average speed.

                        
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