将 RestSharp 请求转换为 HttpClient 请求

Question

I'm programmatically uploading files to a remote server. The files are moderately large and I'd like to present a progress report to my users so they can see something happening. I was able to implement the upload using Postman which helpfully translated the whole thing to RestSharp. But RestSharp does not provide any kind of progress tracking. I tried to implement the same functionality using HttpClient but it goes wrong somewhere the and server just throws a "400 - Bad Request" without telling exactly what is bad about it (its API documentation is also not for the faint of heart).

So, here's what Postman / RestSharp provide and which is working:

var client = new RestClient("https://opencast/ingest/addMediaPackage");
      client.Timeout = -1;
      var request = new RestRequest(Method.POST);
      request.AddHeader("Authorization", "Basic FooBarBaz=");
      request.AddParameter("creator", file.Creator);
      request.AddParameter("title", file.Title);
      request.AddParameter("flavor", "presentation/source");
      request.AddParameter("description", file.Description);
      try
      {
           request.AddFile("BODY", path);
           IRestResponse response = await client.ExecuteAsync(request);
           _logger.LogInformation($"Response after file upload: {response.StatusCode}");
           File.Delete(path);  
      }
      catch (Exception ex)
      {
           _logger.LogError(ex, "Exception when uploading files: {Message}", ex.Message);
      }

and here's what I tried to do with HttpClient (without try-catch):

var request = new HttpRequestMessage(HttpMethod.Post, $"https://opencast/ingest/addMediaPackage");
request.Headers.Add("Authorization", "Basic FooBarBaz=");
using var form = new MultipartFormDataContent();
using var fileContent = new ByteArrayContent(await File.ReadAllBytesAsync(path));
fileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("multipart/form-data");
form.Add(fileContent, "BODY", Path.GetFileName(path));
form.Add(new StringContent(file.Creator), "creator");
form.Add(new StringContent(file.Title), "title");
form.Add(new StringContent("presentation/source"), "flavor");
form.Add(new StringContent(file.Description), "description");
request.Content = form;
var client = clientFactory.CreateClient(); //which is a IHttpClientFactory
var response = await client.SendAsync(request);

This code sends the file to the server which, after completing the upload, throws a 400. Currently not seeing the difference. I could intercept the requests to see where they differ but maybe someone here can see the problem right away?

Update: It gets weirder. If I just use clientFactory.PostAsync(form) and add the Auth headers through form.Add then I get a 200 (ie Success) but the server simply swallows the file.

Answer 1

Okay, I found the solution. I'm not sure whether the WTF is me or the guys behind the server but...

... you need to add the fileContent last .

Yes, the order of the parameters matters for this.