使用httpclient实现后台通过接口上传文件

   var upurl = Config.GetValue("fileupUrl");
   HttpPostedFile file = files[0];
   MemoryStream memoryStream = new MemoryStream();
   file.InputStream.CopyTo(memoryStream);
   byte[] fileBytes = memoryStream.ToArray();
   object sendScObj = new {  relaPath = virtualPath, fileName = fileName };
   ServicePointManager.ServerCertificateValidationCallback += (s, cert, chain, sslPolicyErrors) => true;
   ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;
   var handler = new HttpClientHandler
   {
       ServerCertificateCustomValidationCallback = delegate { return true; }
   };
   using (System.Net.Http.HttpClient client = new System.Net.Http.HttpClient(handler))//若想手动设置Cookie则必须设置UseCookies = false
   {
       var fileContent = new ByteArrayContent(fileBytes);
       fileContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")
       {
           Name = "file",
           FileName = fileName
       };

       var formDataContent = new MultipartFormDataContent();
       formDataContent.Add(fileContent);
       formDataContent.Headers.Add("UserName", "");
       formDataContent.Headers.Add("PassWord", "");
       formDataContent.Headers.Add("SendPlatCode", "");
       var response = await client.PostAsync(upurl, formDataContent);
       response.EnsureSuccessStatusCode();
   }

    [HttpPost]
    public async Task<object> syncReceStream()
    {
        #region 授权
        string AuthcodeID = "";
        var authResult = Authorization(out AuthcodeID);
        if (authResult.Code != ClientCode.Succeed)
        {
            return authResult;
        }
        var ips = Config.GetValue("yxIP");
        var bendiPath = Config.GetValue("BendiPath");
        if (string.IsNullOrEmpty(bendiPath) || string.IsNullOrEmpty(ips) || !ips.Contains(AuthcodeID))
        {
            authResult.Code = ClientCode.FindNull;
            authResult.ErrorMessage = "未找到网络";
            return authResult;
        }
        #endregion
        ApiResultModel apiModel = new ApiResultModel();
        try
        {
            //获取流
            var requestfile = System.Web.HttpContext.Current.Request.Files[0];
            if (requestfile != null && requestfile.ContentLength > 0)
            {
                var request = await Request.Content.ReadAsStringAsync();
                if (string.IsNullOrEmpty(request))
                {
                    apiModel.Code = ClientCode.FindNull;
                    apiModel.ErrorMessage = "未找到参数";
                    return apiModel;
                }
                var model = Util.Json.ToObject<AnnexInfoEntity>(request.ToString());
                var RoutePath = bendiPath + model.RelaPath;
                if (!System.IO.Directory.Exists(RoutePath))
                {
                    System.IO.Directory.CreateDirectory(RoutePath);
                }
                //本地文件夹
                requestfile.SaveAs(RoutePath);
                apiModel.Code = ClientCode.Succeed;
            }
            else
            {
                apiModel.Code = ClientCode.Exception;
                apiModel.ErrorMessage = "文件异常";
            }
        }
        catch (Exception ex)
        {
            apiModel.Code = ClientCode.Exception;
            apiModel.ErrorMessage = ex.Message;
        }
        return apiModel;
    }