Post request error when sending "application/octet-stream" to an ASP.NET Core Web API service - asp.net-core

Question

I need to create an ASP.NET Core 3 Web API that understand this URL
http://myapp.com/MyASPNetCore3WebApi/myController/myWebMethod?user=A0001
and one zipfile which goes as a content. This is the code that calls the needed API, which I need to create:
HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(URI);
httpWebRequest.Timeout = -1;
httpWebRequest.KeepAlive = false;
httpWebRequest.Method = "POST";
httpWebRequest.ProtocolVersion = HttpVersion.Version10;
httpWebRequest.ContentType = "application/octet-stream";
httpWebRequest.Accept = "application/octet-stream";
httpWebRequest.ContentLength = data.Length;
Stream requestStream = httpWebRequest.GetRequestStream();
requestStream.Write(data, 0, data.Length);
requestStream.Close();
HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
The code above is working fine, it is used everyday, sending data to a java web service, now I am replacing that system for a new one in ASP.NET Core and I can't change the caller's code, that's why I need to create a Web API that understand that URL.
I have wrote this code in my Web API, but I guess I am missing something that I can´t figure it out because I get an error ion the client (code above)
[HttpPost("myWebMethod")]
public FileStreamResult myWebMethod(string user, [FromBody] Stream compress)
{
byte[] zip = ((MemoryStream)compress).ToArray();
byte[] data = ZipHelper.Uncompress(zip);
.....................
}
The error I get in the client is this:-
[System.Net.WebException] {"The remote server returned an error: (415)
Unsupported Media Type."} System.Net.WebException
Thanks in advance for any help

Answer 1

If the goal is to read the raw request content, this can be done using HttpContext controller property. HttpContext has Request property that provides access to the actual HTTP request.
No additional model properties or controller arguments are needed to access raw request stream. It's important to note that FromBody and FromForm binding should not be used in this case.
There are couple notes regarding the code in the example from the original question.
byte[] zip = ((MemoryStream)compress).ToArray();
byte[] data = ZipHelper.Uncompress(zip);
The HttpContext.Request.Body property does not return MemoryStream, it returns its own implementation of a Stream. It means that there is no ToArray method.
When reading the entire content of a request directly into the server's memory, it is better to check the content length, otherwise the client can crash the server by sending a large enough request.
Using *Async methods when reading the content of the request will improve performance.