为什么Aws s3在动态创建新文件夹的同时上传文件时创建0字节文件？

Question

我对Aws s3存储桶很新，我正在尝试动态上传不同文件夹创建的文件。即使我的脚本正常工作。我的s3存储桶创建0字节文件，并且名称等于上次上传的文件夹。  

这是我的server.js

import express from 'express';
import path from 'path';
import webpack from 'webpack';
import webpackMiddleware from 'webpack-dev-middleware'
import webpackHotMidleware from 'webpack-hot-middleware';
import bodyParser from 'body-parser';
import AWS from 'aws-sdk';
import open from 'open';
import uuid from 'uuid'

import webpackConfig from './webpack.config';


// Create an S3 client
AWS.config.loadFromPath('c.json');
var s3 = new AWS.S3();

// Create a bucket and upload something into it






let app = express();
app.use(bodyParser.json({limit:"50mb"}));
app.use(express.static('public'));



const compiler = webpack(webpackConfig)

app.use(webpackMiddleware(compiler,{
    hot:true,
    publicPath:webpackConfig.output.publicPath,
    noInfo:true
}));

app.use(webpackHotMidleware(compiler));



app.post('/api',(req,res) => {

    let imageuri = req.body.data.data_uri;
    let filename = req.body.data.filename;
    let filetype = req.body.data.filetype;

     const Name = uuid.v1();
    var bucketName = 'nok-sample/'+Name;


    let buf = new Buffer(imageuri.replace(/^data:image\/\w+;base64,/, ""),'base64');
    console.log(buf.length);



    s3.createBucket({Bucket: bucketName}, function() {
        var params = {Bucket: bucketName, Key: filename, Body: buf,ContentType:filetype,ContentLength:buf.length,ACL:'public-read'};
        s3.putObject(params, function(err, data) {
            if (err)
                console.log(err)
            else
                console.log("Successfully uploaded data to " + bucketName + "/" + filename);
                let resimage = {
                    "awsUrl":`https://s3.amazonaws.com/${bucketName}/${filename}`
                };
                res.json(resimage);
                console.log(resimage)

        });
    });
});



app.get('/*',(req,res) => {
    res.sendFile(path.join(__dirname,'./index.html'))
});


app.listen(3000,() => {
    open('http://localhost:3000')
});