音频流断点续传处理

1、新建 express 实例应用，解析url、json、接入路由，监听端口

const express = require('express')
const app = express();
app.use(express.urlencoded({ extended: false }))
app.use(express.json())
const Router = require('./router')
app.use(Router)
app.listen(3200,()=>{
  console.log('App listening on port 3200!')
})

2、处理流媒体文件

const express = require('express');
const fs = require('fs')
const route = express.Router();
route.get('/music/:fileName', async (req, res) => {
  let fileName = req.params.fileName;
  let range = req.headers.range;
  let audioUrl = `./audios/${fileName ?? ''}`;
  if (range) {
    let stat = await fs.promises.stat(audioUrl);
    let rangeArr = range.match(/=(\d+)-(\d+)?/);
    let rangeStart = parseInt(rangeArr[1], 10);
    let rangeEnd = rangeArr[2] ? parseInt(rangeArr[2], 10) : stat.size;
    console.log('hello world',{fileName,rangeStart,rangeEnd,totalSize:stat.size}) 
    if (rangeEnd > stat.size - 1) {
      rangeEnd = stat.size - 1
    }
    let header = {
      "Content-Type": "audio/mpeg;charset=UTF-8",
      "Content-Range": `bytes ${rangeStart} - ${rangeEnd} / ${stat.size}`,
      "Content-Length": rangeEnd - rangeStart + 1,
      "Accept-Ranges": 'bytes',
    }
    res.writeHead(206, header);
    let readStream = fs.createReadStream(audioUrl, { start: rangeStart, end: rangeEnd });
    readStream.pipe(res)
  } else {
    let readStream = fs.createReadStream(audioUrl,);
    readStream.pipe(res)
  }
})
module.exports = route