C# 多部分表单数据 httpclient 上传 csv 服务

Question

I have a windows service that is uploading a multipart data form in C#. It is uploading a csv with authentication variables in the form: a key, a context, and a uuid. The variables are set in a custom Token class. Each time I try to upload, I get a 403 error.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace UploadScheduler.Service
{
    class UploadHttp
    {
        // HttpClient is instantiated once per application
        static readonly HttpClient client = new HttpClient();
        //myUserKey and myUuid are redacted values
        public static string userKey = "myUserKey";
        public static string uuid = "myUuid";

        public static void UploadFile(FileInfo file, Token token, DateTime lwt, DateTime nwt)
        {
            FileInfo fi = new FileInfo(file.FullName);
            string fileName = fi.Name;
            byte[] fileContents = File.ReadAllBytes(fi.FullName);
            Uri webService = new Uri(token.Url);
            HttpRequestMessage requestMessage = new HttpRequestMessage(HttpMethod.Post, webService);
            requestMessage.Headers.ExpectContinue = false;
            HttpWebRequest webRequest = WebRequest.CreateHttp(token.Url);
            webRequest.ServicePoint.Expect100Continue = false;
            MultipartFormDataContent multiPartContent = new MultipartFormDataContent();
            ByteArrayContent byteArrayContent = new ByteArrayContent(fileContents);
            byteArrayContent.Headers.Add("Content-Type", "text/csv");
            multiPartContent.Add(byteArrayContent, "file", fileName);
            multiPartContent.Add(new StringContent(token.Key), "key");
            multiPartContent.Add(new StringContent(token.Context), "context");
            multiPartContent.Add(new StringContent(token.Uuid), "uuid");
            requestMessage.Content = multiPartContent;

            try
            {
                //Task<HttpResponseMessage> httpRequest = client.SendAsync(requestMessage, HttpCompletionOption.ResponseContentRead, CancellationToken.None);
                Task<HttpResponseMessage> httpRequest = client.PostAsync(token.Url, multiPartContent, CancellationToken.None);
                HttpResponseMessage httpResponse = httpRequest.Result;
                HttpStatusCode statusCode = httpResponse.StatusCode;
                HttpContent responseContent = httpResponse.Content;

                if (responseContent != null)
                {
                    Task<String> stringContentsTask = responseContent.ReadAsStringAsync();
                    String stringContents = stringContentsTask.Result;
                    Library.RecordUpload(file, lwt, nwt);
                }
            }
            catch (Exception ex)
            {
                Library.WriteLog("Upload Error: " + file.Name + " " + ex.Message);
                //Library.WriteLog(ex.StackTrace);
            }
        }
    }
}

I am trying to upload to an Amazon S3 Bucket, and the bucket is handled through a third party. I have been told that my request is malformed; however, when I try this in http://www.webhook.com , it successfully uploads and shows the form values as entered.

Is there something that I am missing in my code? Or is it a policy/permission issue from the third party? This multipartformdata & httpclient is new to me, so I don't what I'm missing, if anything.

Original code: https://dotnetcodr.com/2013/01/10/how-to-post-a-multipart-http-message-to-a-web-service-in-c-and-handle-it-with-java/

AWS S3 Errors: https://aws.amazon.com/premiumsupport/knowledge-center/s3-403-forbidden-error/

In my development process, I did create my own S3 bucket and I added the NuGet AWS S3 class, which was able to upload files successfully. Now that I am uploading to a 3rd party bucket, I keep getting a 403 error. Thanks!

Answer 1

I went the route of using Postman to create my request, then got the generated code for C# with the RestSharp NuGet Package.

public static void UploadFile(FileInfo file, Token token, DateTime lwt, DateTime nwt)
        {
            string status = "";
            string reason = "";
            try
            {
                var client = new RestClient(token.Url);
                client.Timeout = -1;
                var request = new RestRequest(Method.POST);
                request.AddParameter("key", token.Key);
                request.AddParameter("uuid", token.Uuid);
                request.AddParameter("context", token.Context);
                request.AddFile("file", file.FullName);
                IRestResponse response = client.Execute(request);
                status = response.StatusCode.ToString();
                reason = response.ErrorMessage.ToString();
                Library.RecordUploadSuccess(file, lwt, nwt);
            }
            catch (Exception ex)
            {
                Library.RecordUploadError(file, status, reason);
                //Library.RecordUploadError(file, ex.Message, ex.StackTrace);
            }
        }

Highly recommend going that route for multipart form-data.