Node.js PassThrough流：数据透明传递与合并实战

'use strict';
const fs = require('fs');
const { PassThrough } = require('stream');
// 创建一个 PassThrough 流作为中间层
const logStream = new PassThrough();
// 创建一个文件可写流，将日志写入到文件中
const fileStream = fs.createWriteStream('app.log');
logStream.pipe(fileStream);
// 将日志信息输出到控制台
logStream.on('data', (chunk) => {
  console.log('Log:', chunk.toString());
});
// 模拟写入日志
logStream.write('This is a log message.\n');
logStream.write('Another log message.\n');
logStream.end();

'use strict';
const Controller = require('egg').Controller;
const { createReadStream } = require('fs');
const { join } = require('path');
const { spawn } = require('child_process');
const { PassThrough } = require('stream');
class HomeController extends Controller {
  async testStream() {
    ctx.set('Content-Type', 'text/plain; charset=utf-8');
    const shPath = join(__dirname, './test.sh');
    const childProcess = spawn('sh', [ shPath ]);
    // 创建内存中的可读写流
    const memoryStream = new PassThrough();
    // 将子进程的 stdout 输出流写入内存流
    childProcess.stdout.pipe(memoryStream);
    // 将子进程的 stderr 输出流写入内存流
    childProcess.stderr.pipe(memoryStream);
    ctx.body = memoryStream;
  }
}
module.exports = HomeController;