Koa2-如何写入响应流? [英] Koa2 - How to write to response stream?

问题描述

使用Koa2，我不确定如何将数据写入响应流，因此在Express中，它类似于:

Using Koa2 and I'm not sure how to write data to the response stream, so in Express it would be something like:

res.write('some string');

我知道我可以为ctx.body分配流，但是我对node.js流太不熟悉，所以不知道如何创建该流.

I understand that I can assign a stream to ctx.body but I'm not familiar with node.js streams too well so don't know how I would go about creating this stream.

推荐答案

koa文档允许您将流分配给响应:(来自 https://koajs.com/#response )

The koa documentation allows you to assign a stream to your response: (from https://koajs.com/#response)

ctx.response.body =

将响应主体设置为以下之一:

Set response body to one of the following:

• 写的字符串
• 缓冲区已写
• 流式传输
• 对象||数组json-stringified
• 无内容响应

ctx.body只是ctx.response.body

因此，这里有一些示例，您将如何使用它(加上标准的koa主体分配)

So here are some examples how you could use it (plus standard koa body assignment)

通过调用服务器 -本地主机:8080/stream ...将以数据流响应 -本地主机:8080/file ...将以文件流响应 -本地主机:8080/...仅发送回标准正文

Calling the server with - localhost:8080/stream ... will respond with the data stream - localhost:8080/file ... will respond with the file stream - localhost:8080/ ... just sends back standard body

'use strict';
const koa = require('koa');
const fs = require('fs');

const app = new koa();

const readable = require('stream').Readable
const s = new readable;

// response
app.use(ctx => {
    if (ctx.request.url === '/stream') {
        // stream data
        s.push('STREAM: Hello, World!');
        s.push(null); // indicates end of the stream
        ctx.body = s;
    } else if (ctx.request.url === '/file') {
        // stream file
        const src = fs.createReadStream('./big.file');
        ctx.response.set("content-type", "txt/html");
        ctx.body = src;
    } else {
        // normal KOA response
        ctx.body = 'BODY: Hello, World!' ;
    }
});

app.listen(8080);

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