node.js - 如何克隆可读流

Question

我有一个流，我正在尝试将相同的流提交到两个不同的目的地。第一个目的地是 AWS S3，第二个目的地是通过 http 请求到达其他后端。

const document = fs.createReadStream(process.cwd() + "/test/resources/" + "id/document.jpg");

const s3Response = await submitToS3(document);

const backendResponse = await submitToBackend(document);

据我了解，流只能读取一次。我如何将相同的流发送到两个不同的目的地。

我考虑过克隆流，但简单地创建一个新变量并将流分配给该变量是行不通的。

Answer 1

你可以检查这个npm模块:https://www.npmjs.com/package/readable-stream-clone

npm install readable-stream-clone

const fs = require("fs");
const ReadableStreamClone = require("readable-stream-clone");
 
const readStream = fs.createReadStream('text.txt');
 
const readStream1 = new ReadableStreamClone(readStream);
const readStream2 = new ReadableStreamClone(readStream);
 
const writeStream1 = fs.createWriteStream('sample1.txt');
const writeStream2 = fs.createWriteStream('sample2.txt');
 
readStream1.pipe(writeStream1)
readStream2.pipe(writeStream2)