鸿蒙文件上传-从前端到后端详解，对比jq请求和鸿蒙arkts请求区别，对比new FormData()和鸿蒙arktsrequest.uploadFile

需要权限：ohos.permission.INTERNET

1.nodejs自定义书写上传后端接口

传输过来的数据放在files?.image下

router.post('/upload',(req, res) => {
  var form = new multiparty.Form();
  form.uploadDir='public/images/uploads'; //上传图片保存的地址(目录必须存在)
  form.parse(req, function(err, fields, files) {// 1、fields:获取表单的数据 2、files：图片上传成功返回的信息
    console.log(files,fields)
    const fileurl = Date.now()+ files?.image[0]?.originalFilename;
    let newPath = form.uploadDir + '/' +fileurl
    fs.renameSync(files.image[0].path,newPath);
    let imgUrl = myUrl.myUrl+'/images/uploads/' +fileurl
    
    res.send({
      code: '200',
      message: '数据上传成功',
      data:imgUrl
    })
  })
})

2，在jq中请求(new FormData())

        var fileImg;
        //读取图片
        function fileUpload(_this) {
            var fileReader = new FileReader();//创建文件读取对象
            fileImg = _this.files[0];//获取file组件中的文件
        }
        //上传图片
        function uploadPictures() {
            var formData = new FormData();
            //图片
            if (fileImg != null) {
              formData.append("image", fileImg);
            }
            $.ajax({
             url: 'http://localhost:3333/api/img/upload',
                type: 'post',
                data: formData,
                processData: false,
                contentType: false,
                success: function (res) {
                    // var res = JSON.parse(res);
                    console.log('upload success', res);
                    // $('.img').attr('src', res.path);
                    debugger
                },
                error: function (err) {
                    console.log('upload error', err);
                    console.log(err);
                }
            });
        }

3.对比在鸿蒙arkts请求如下 -试用相册的场景

参考官网

1.假设数据来源于相册，以下是获取相册的数据，photoSelectResult.photoUris[0]是一个目录的路径， 但是不是context.cacheDir的路径，

试用下载必须要在cacheDir目录下面

 async selectPhoto() {
    try {
      let PhotoSelectOptions = new photoAccessHelper.PhotoSelectOptions();
      PhotoSelectOptions.maxSelectNumber = 1;
      PhotoSelectOptions.MIMEType = photoAccessHelper.PhotoViewMIMETypes.IMAGE_TYPE;
      let textInfo: photoAccessHelper.TextContextInfo = {
        text: '人像'
      };
      let recommendationOptions: photoAccessHelper.RecommendationOptions = {
        textContextInfo: textInfo
      };
      PhotoSelectOptions.recommendationOptions =
        recommendationOptions; // 将推荐参数赋值给 photoSelectOptions.recommendationOptions
      let photoPicker = new photoAccessHelper.PhotoViewPicker();
      let photoSelectResult = await photoPicker.select(PhotoSelectOptions)
      if (photoSelectResult.photoUris.length == 1) {
        this.uploadFile(photoSelectResult.photoUris[0])
      }
    } catch (error) {
      let err: BusinessError = error as BusinessError;
    }
  }

2.因为必须是cacheDir目录，从相册拿到的的图片就复制一份存在cacheDir

  // 提取文件扩展名的函数
  getFileExtension(fileName: string): string {
    const lastDotIndex = fileName.lastIndexOf('.');
    if (lastDotIndex !== -1 && lastDotIndex  
3。知道了cacheDir目录就组装参数
 
   let files: Array = [
    //uri前缀internal://cache 对应cacheDir目录
      {
        filename: names,
        name: 'image',  // 必须是image，因为接口拿的数据就是这个的第0项
        uri: 'internal://cache/' + names,
        type: extensionName
      }
    ]
let data: Array = [{ name: 'name', value: 'value' }];
    let uploadConfig: request.UploadConfig = {
      url: 'http://xxxxxxxxxxxxxxxx/api/img/upload',
      header: {
      // 根据项目添加
},
      method: 'POST',
      files: files,
      data: data,
    }
// 将本地应用文件上传至网络服务器
try {
  request.uploadFile(context, uploadConfig)
    .then((uploadTask: request.UploadTask) => {
 let headerCallback = (value: object) => {
            let str = JSON.stringify(value)
            
            console.log("http:success:", JSON.stringify(rstr ))
          };
 uploadTask.on('headerReceive', headerCallback);
    })
    .catch((err: BusinessError) => {
      console.error(`Invoke uploadFile failed, code is ${err.code}, message is ${err.message}`);
    })
} catch (error) {
  let err: BusinessError = error as BusinessError;
  console.error(`Invoke uploadFile failed, code is ${err.code}, message is ${err.message}`);
}
 
缓存目录在cacheDir ="/data/app/el2/100/base/{找到自己的包名}/haps/entry/cache”
 
 
原理总结
 
使用相册拿到的路径，复制一份放在缓存路径下， request.uploadFile(只能读缓存的路径。
通过 uploadTask.on(‘headerReceive’, headerCallback);拿到后端给我们的响应数据code
 
官网也还提供了request.agent，可查看文档使用
https://developer.huawei.com/consumer/cn/doc/harmonyos-guides/app-file-upload-download#%E4%B8%8A%E4%BC%A0%E5%BA%94%E7%94%A8%E6%96%87%E4%BB%B6