HarmonyOS鸿蒙Next中使用request.uploadFile上传3MB PPT，上传的文件损坏

可以给大家看看我上传部分的代码，我本人没发现什么问题

uploadPPTFn(fileUrl: string): void {
  let context = this.getUIContext().getHostContext() as common.UIAbilityContext;
  let uploadTask: request.UploadTask;
  let fileName = fileUrl.substring(fileUrl.lastIndexOf('/') + 1);
  this.fileName = decodeURI(fileName)
  this.uploadTitle = this.fileName
  let newpath = context.cacheDir + "/"+fileName//+".pptx";
  fs.open(fileUrl,2).then((file: fs.File) => {
    console.info("file fd: " + file.fd);
    fs.copyFile(file.fd, newpath, (err: BusinessError) => {
      if (err) {
        this.uploadStatus = 'fault'
        console.error("copy file failed with error message: " + err.message + ", error code: " + err.code);
        return
      } else {
        console.info("copy file succeed");
      }
      fs.closeSync(file);
    });
  }).catch((err: BusinessError) => {
    this.uploadStatus = 'fault'
    console.error("open file failed with error message: " + err.message + ", error code: " + err.code);
    return
  });
  //获取文件大小
  this.getFileSize(newpath);
  let realuri = "internal://cache/" + newpath.split("cache/")[1]//.split(".pptx")[0]+".pptx";
  console.log('applog:realuri' + realuri);
  //获取了沙箱真实internal格式路径，继续对照准备参数

  let uploadConfig: request.UploadConfig = {
    url: Const.G_AjaxApi_activity + "/api/ai/uploadPPT", // HTTP协议地址
    header: { "Content-Type": "multipart/form-data" },
    method: "POST",
    files: [{
      filename: fileName,
      name: "file",
      uri: realuri,
      type: 'application/vnd.openxmlformats-officedocument.presentationml.presentation'
    }], // 建议type填写HTTP协议规范的MIME类型
    data: [{ name: "guid", value: this.guid },
      { name: "appID", value: this.appId.toString() },
      { name: "presentations_id", value: this.presentations_id.toString()},
      { name: "provinces", value: this.province },],
  };

  try {
    request.uploadFile(getContext(this), uploadConfig).then((data:request.UploadTask) => {
      uploadTask = data;
      console.log('上传文件成功：');
      uploadTask.on("complete",(data)=>{
        console.log("上传完成:"+JSON.stringify(data))
      })
      uploadTask.on("headerReceive",(data)=>{
        console.log("headerReceive"+JSON.stringify(data))
        let result:uploadResponse = data as uploadResponse
        console.log("***"+result.body)
        let tempUrl = result.body.split('url":"')[1]
        let tempName = tempUrl.split('","name":"')[1]
        let tempOssPath = tempName.split('","ossPath":"')[1]
        let tempPresentations_id = tempOssPath.split('","presentations_id":')[1]

        tempUrl = tempUrl.split('","name":"')[0]
        tempName = tempName.split('","ossPath":"')[0]
        tempOssPath = tempOssPath.split('","presentations_id":')[0]
        tempPresentations_id = tempPresentations_id.split(',')[0]

        this.uploadData.url = tempUrl
        this.uploadData.name = tempName
        this.uploadData.ossPath = tempOssPath
        this.uploadData.presentations_id = Number.parseInt(tempPresentations_id)
        this.uploadStatus = 'complete'
        console.log("PPT上传全过程结束"+JSON.stringify(this.uploadData))
      })
    }).catch((e: BusinessError) => {
      this.uploadStatus = 'fault'
      console.error('Failed to request the upload. Cause: ' + JSON.stringify(e));
    });

  } catch (err) {
    this.uploadStatus = 'fault'
    console.error('applog:' + JSON.stringify(err));
    console.error('err.code : ' + err.code + ', err.message : ' + err.message);
  }
}