有时候，为了追求便利性，我们可能会让前端直接将文件上传到阿里云OSS，然后将URL提交给ASP.NET。然而，这种做法意味着前端需要拥有OSS的访问密钥，而将密钥存放在前端，无疑增加了被破解的风险。因此，最安全的做法仍然是由服务器端负责上传文件到OSS。

接下来，我将演示如何实现分块上传到服务器的过程，而且在这个过程中，服务器并不保存任何分块，而是直接将分块上传到OSS。

服务器端

---

asp.net 引用 nuget 包：
JMS.FileUploader.AspNetCore
Aliyun.OSS.SDK.NetCore

实现一个oss的 IUploadFilter ， 把接收到的分块数据，实时传到oss

    [UploadFilterDescription("Aliyun")]
    public class AliyunUploadFilter : IUploadFilter
    {
        const string BucketName = "";
		const string OssEndpoint = "";
		const string AccessKeyId = "";
		const string AccessKeySecret = "";

        string _uploadId;
        string _ossUploadId;
        
        string _objectKey;
        OssClient _ossClient;
        public async Task OnUploadBeginAsync(HttpContext context, string uploadId, string fileName, long fileSize, int fileItemIndex)
        {
            _uploadId = uploadId;

            _objectKey = $"file{fileItemIndex}.zip";

            _ossClient = new OssClient(OssEndpoint , AccessKeyId , AccessKeySecret );

            var ret = _ossClient.InitiateMultipartUpload(new InitiateMultipartUploadRequest(BucketName, _objectKey));
            if (ret.HttpStatusCo服务器托管网de != System.Net.HttpStatusCode.OK)
                throw new Exception(ret.HttpStatusCode.ToString());

            _ossUploadId = ret.UploadId;
        }

        public async Task OnReceivedAsync(HttpContext context, Stream inputStream, long position, int size)
        {

            var data = new byte[size];
            await inputStream.ReadAtLeastAsync(d服务器托管网ata, size);

            using var ms = new MemoryStream(data);

         
            var num = (int)(position / 102400) + 1;
            var ret = _ossClient.UploadPart(new UploadPartRequest(BucketName, _objectKey, _ossUploadId) { 
                InputStream = ms,
                
                PartSize = size,
                PartNumber = num
            });

            if (ret.HttpStatusCode != System.Net.HttpStatusCode.OK)
                throw new Exception(ret.HttpStatusCode.ToString());
        }


        public async Task OnUploadCompletedAsync(HttpContext context)
        {

            for (int i = 0; i 

然后注册这个 filter :

services.AddFileUploadFilter();

启用上传组件：

app.UseJmsFileUploader();

controller里面写一个最终的业务处理函数

    [ApiController]
    [Route("[controller]/[action]")]
    public class MainController : ControllerBase
    {

        [HttpPost]
        public string Test([FromBody] object body)
        {
            var customHeader = Request.Headers["Custom-Header"];

            //临时文件路径
            var filepath = Request.Headers["FilePath"];

            //文件名
            var filename = Request.Headers["Name"];
            return filepath + "rn" + filename + "rn" + customHeader;
        }
    }

前端

---

前端 import 模块：jms-uploader

    async function uploadToAliyun() {
        //自定义请求头
        var headers = function () {
            return { "Custom-Header": "test" };
        };

        //提交的body
        var dataBody = {
            name: "abc"
        };

        var uploader = new JmsUploader("http://localhost:5200/Main/Test", [document.querySelector("#file1").files, document.querySelector("#file2").files], headers, dataBody);

        uploader.setPartSize(1024*300);//设置分块大小300K
        uploader.setUploadFilter("Aliyun");//设置服务器使用哪个upload filter

        uploader.onUploading = function (percent, uploadedSize, totalSize) {
            document.querySelector("#info").innerHTML = percent + "% " + uploadedSize + "," + totalSize;
        };

        try {
            var ret = await uploader.upload();
            alert(ret);
        } catch (e) {
            alert("错误：" + JSON.stringify(e));
        }
    }

html

    
    
    
        upload to aliyun oss
    
    

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