在node.js express中按部分发送数据 [英] Send data by parts in node.js express

问题描述

我在网上和文档中搜索node.js express模块，看来没有办法按部就班地发送数据.我的文件渲染速度不是很快，我想在渲染所有文件之前先发送其中的一部分.

I was searching the web and documentation for node.js express module and it seems there is no way to send data by parts. I have a file rendered not very fast and I want to send parts of it before everything is rendered.

这是我的问题:

1. response上是否有一种方法可以按部分发送数据?
2. response.end()是什么?
3. 如果无法按部就班地发送数据-背后的原理是什么?我要说的是，如果是这样的话，它看起来比不阻止更具阻塞性.如果较早提供数据，浏览器可以更快地加载信息.

1. Is there a method on response to send data by parts?
2. What does response.end()?
3. If there is no way to send data by parts - what is the rationale behind? I would say it looks more blocking than non-blocking if that's true. Browser can load information faster if data is given earlier.

示例简化代码:

app.get(..) {
  renderFile(file, function(data) {
    response.send(data);
  });
  response.end();
)

这段代码仅发送第一个数据块.我检查了-正确给出了数据 ，并且多次调用了回调函数.

This piece of code sends only the first chunk of data. I checked - data is given correctly and callback is called more than one time.

我当然可以将数据附加到一个变量中，然后编写response.send(data);，但是我不喜欢这种方法-这不是它应该起作用的方式.

Of course I can append data to the one variable and then write response.send(data); but I don't like this approach - it is not the way it should work.

推荐答案

response对象是可写流.只需对其进行写入，Express甚至会自动为您设置分块编码.

The response object is a writable stream. Just write to it, and Express will even set up chunked encoding for you automatically.

response.write(chunk);

如果正在创建此文件"的任何内容将其自身呈现为可读流，您也可以通过管道进行传输. http://nodejs.org/api/stream.html

You can also pipe to it if whatever is creating this "file" presents itself as a readable stream. http://nodejs.org/api/stream.html

这篇关于在node.js express中按部分发送数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！