node koa2实现上传图片并且同步上传到七牛云存储

因为升级到新的node版本，之前的通过很多上传图片的方式都已经不适用了，所以自己就写了一个对于 koa2上传图片的小demo,记录一下心得。

废话不多说，下面直接上代码，里面都有注释。

const Koa = require('koa');
const route = require('koa-route');
const serve = require('koa-static');
const inspect = require('util').inspect
const path = require('path')
const os = require('os')
const fs = require('fs')
const Busboy = require('busboy')
const qiniu = require('qiniu')
const qiniuConfig = require('./qiniuconfig')

const app = new Koa();

app.use(serve(__dirname + '/public/'));

// 写入目录
const mkdirsSync = (dirname) => {
 if (fs.existsSync(dirname)) {
  return true
 } else {
  if (mkdirsSync(path.dirname(dirname))) {
   fs.mkdirSync(dirname)
   return true
  }
 }
 return false
}

function getSuffix (fileName) {
 return fileName.split('.').pop()
}

// 重命名
function Rename (fileName) {
 return Math.random().toString(16).substr(2) + '.' + getSuffix(fileName)
}
// 删除文件
function removeTemImage (path) {
 fs.unlink(path, (err) => {
  if (err) {
   throw err
  }
 })
}
// 上传到七牛
function upToQiniu (filePath, key) {
 const accessKey = qiniuConfig.accessKey // 你的七牛的accessKey
 const secretKey = qiniuConfig.secretKey // 你的七牛的secretKey
 const mac = new qiniu.auth.digest.Mac(accessKey, secretKey)

 const options = {
  scope: qiniuConfig.scope // 你的七牛存储对象
 }
 const putPolicy = new qiniu.rs.PutPolicy(options)
 const uploadToken = putPolicy.uploadToken(mac)

 const config = new qiniu.conf.Config()
 // 空间对应的机房
 config.zone = qiniu.zone.Zone_z2
 const localFile = filePath
 const formUploader = new qiniu.form_up.FormUploader(config)
 const putExtra = new qiniu.form_up.PutExtra()
 // 文件上传
 return new Promise((resolved, reject) => {
  formUploader.putFile(uploadToken, key, localFile, putExtra, function (respErr, respBody, respInfo) {
   if (respErr) {
    reject(respErr)
   }
   if (respInfo.statusCode == 200) {
    resolved(respBody)
   } else {
    resolved(respBody)
   }
  })
 })

}

// 上传到本地服务器
function uploadFile (ctx, options) {
 const _emmiter = new Busboy({headers: ctx.req.headers})
 const fileType = options.fileType
 const filePath = path.join(options.path, fileType)
 const confirm = mkdirsSync(filePath)
 if (!confirm) {
  return
 }
 console.log('start uploading...')
 return new Promise((resolve, reject) => {
  _emmiter.on('file', function (fieldname, file, filename, encoding, mimetype) {
   const fileName = Rename(filename)
   const saveTo = path.join(path.join(filePath, fileName))
   file.pipe(fs.createWriteStream(saveTo))
   file.on('end', function () {
    resolve({
     imgPath: `/${fileType}/${fileName}`,
     imgKey: fileName
    })
   })
  })

  _emmiter.on('finish', function () {
   console.log('finished...')
  })

  _emmiter.on('error', function (err) {
   console.log('err...')
   reject(err)
  })

  ctx.req.pipe(_emmiter)
 })
}

app.use(route.post('/upload', async function(ctx, next) {

  const serverPath = path.join(__dirname, './uploads/')
 // 获取上存图片
 const result = await uploadFile(ctx, {
  fileType: 'album',
  path: serverPath
 })
 const imgPath = path.join(serverPath, result.imgPath)
 // 上传到七牛
 const qiniu = await upToQiniu(imgPath, result.imgKey)
 // 上存到七牛之后 删除原来的缓存图片
 removeTemImage(imgPath)
 ctx.body = {
  imgUrl: `http://xxxxx(你的外链或者解析后七牛的路径)/${qiniu.key}`
 }
}));

app.listen(3001);

console.log('listening on port 3001');

然后在同一级目录下，创建一个public文件夹，然后在下面新建一个 index.html，因为我们上面已经把这个文件夹设置为静态访问文件夹了， public/index.html 的代码为

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>
  <input id="btn1" type="file" name="file"/>
 <input id="btn2" type="submit" value="提交"/>
</body>
<script>

  var btn1 = document.querySelector('#btn1')
  var btn2 = document.querySelector('#btn2')
  var file = null
  btn1.addEventListener('change', function(e){
    file = e.target.files[0]
  })

  btn2.onclick = function(){
  var _data = new FormData();
  _data.append('file', file);
  xhr(_data)
  }

  var xhr = function(formdata){
    var xmlHttp = new XMLHttpRequest(); 

    xmlHttp.open("post","http://127.0.0.1:3001/upload", true); 

    xmlHttp.send(formdata);

    xmlHttp.onreadystatechange = function(){
     if(xmlHttp.readyState==4){
       if(xmlHttp.status==200){
         var data = xmlHttp.responseText;
         console.log(data);
       }
     }
    }
  }
</script>
</html>

选择好图片，然后点击提交，就可以上传到你的七牛空间啦！

源代码在 github: https://github.com/naihe138/koa-upload

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。