HttpRequest works in postman but not in .Net Core-CodePudding

So, I have a POST request to upload a file. I'm able to do that request inside a postman with simple settings like this: Body: form-data, body has only one item. Key=file, Value=xxxx.pdf

No authorization. Final working request from postman console looks like this:

Request Headers
User-Agent: PostmanRuntime/7.26.8
Accept: */*
Cache-Control: no-cache
Postman-Token: 8d5df709-8f9e-48e2-bf20-f300b24d4be8
Host: api.xxxx.com
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Content-Type: multipart/form-data; boundary=--------------------------138420394858496796018969
Cookie: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Content-Length: 976797
Request Body
file: undefined

This works and file gets uploaded. But when I do the same thing in .net Core, it fails every time (400 - bad request)

using (var message = new HttpRequestMessage(HttpMethod.Post, uploadUri))
{
    using (var fileStream = new FileStream(fileInfo.FullName, FileMode.Open, FileAccess.Read))
    using (var formDataContent = new MultipartFormDataContent())
    {
        using (var fileContent = new StreamContent(fileStream))
        {
            formDataContent.Add(fileContent, "file");
            message.Content = formDataContent;

            using (var response = await httpClient.SendAsync(message, HttpCompletionOption.ResponseHeadersRead))
            {
                response.EnsureSuccessStatusCode();
            }
        }
    }
}

Edit: Only difference that I can see is the content-disposition header being added to StreamContent. Hovewer I was not able to remove this header.

Edit: After a talk with the developer of the API, the problem is 100% the body & headers of the request. Api does not want a content-disposition header and excpects body multipart/form-data with pair file=byteArray

CodePudding user response：

I do believe you're missing Content-Type header value set:

fileStreamContent.Headers.ContentType = new MediaTypeHeaderValue("image/png");

I've tested with a *.jpg file and it works OK:

using (var multipartFormContent = new MultipartFormDataContent())
{
   //Load the file and set the file's Content-Type header
   var fileStreamContent = new StreamContent(File.OpenRead(filePath));
   fileStreamContent.Headers.ContentType = new MediaTypeHeaderValue("image/png");

   //Add the file to form
   multipartFormContent.Add(fileStreamContent, name: "file", fileName: filePath);

   //Send it
   var response = await new HttpClient().PostAsync("http://localhost:5000/[Controller]/[Action]", multipartFormContent);
   response.EnsureSuccessStatusCode();
}

CodePudding user response：

Might be security issue, try to add this before HTTP request code

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11;