直接从小程序上传图片到COS

我想知道这是可能到吗？我一直得到报错“The body of your POST request is not well-formed multipart/form-data.”

我用一个云函数计算所需要到Auth，返还这个Auth给微信小程序后我想直接用wx.uploadFile上传图片到COS。以下是我实际的代码

wx.uploadFile({       url: "https://bucketname-appid.cos.ap-guangzhou.myqcloud.com",       filePath: this.data.imgSrc, // 这个imgSrc看起来是这样的 http://tmp/wx06831dfa43ec02c8.tGEdCWwps.6OYqN...jHa01.jpg       name: 'file',       header: {           'Authorization': resData.data, // 这里的data看起来是这样的 q-sign-algorithm=sha1&q-ak=AKIDK1a...&q-sign-time=1538223445;1538222464&q-key-time=1538223445;1538222464&q-header-list=&q-url-param-list=&q-signature=23b157...           "Content-Type": "multipart/form-data",            'Host': "bucketname-appid.cos.ap-guangzhou.myqcloud.com"       },       success: function (uploadRes) {           console.log('ssss::: ', uploadRes)       },       fail: function (e) {           console.log('e', e)       }   });

**我用“bucketname-appid"代替了真实的bucketname和appid

这段代码会运行success中的callback，console.log显示如下

1. data:"<?xml version='1.0' encoding='utf-8' ?>↵<Error>↵ <Code>MalformedPOSTRequest</Code>↵

   <Message>The body of your POST request is not well-formed multipart/form-data.</Message>↵

   <Resource>bucketname-appid.cos.ap-guangzhou.myqcloud.com</Resource>↵

   <RequestId>NWJh....FiMTc=</RequestId>↵

   <TraceId>OGVm...gzMzdjOTA=</TraceId>↵</Error>↵↵"

2. errMsg:"uploadFile:ok"

3. statusCode:400