NetCore API controller will not accept files uploaded using FromBody

Question

I'm trying to create a POST api controller for my .NET Core 3.1 web app so gamers can upload screenshots of their gaming experiences.

This is a little different scenario, because this API will be used by a Unity game that is compiled into WebGL.

So I am thinking I can't use [FromForm].

Anyway, I wrote this:

    [HttpPost]
    public async Task<IActionResult> SubmitScreens([FromBody] IFormFile file)
    {
        //C:\inetpub\wwwroot\gamerProfiles\screenGrabs\
        string contentRootPath = _hostingEnvironment.ContentRootPath;

        // get the folder path
        var uploads = Path.Combine(contentRootPath, "pic_upload_testing");

        // make the file path for the uploading
        var filePath = Path.Combine(uploads, file.FileName);

        using (var fileStream = new FileStream(filePath, FileMode.Create))
        {
            await file.CopyToAsync(fileStream);
        }
        return Ok();

    }

I am testing in postman.

I am sending it as

"Content-Type: application/octet-stream"

as my header and 'binary' as my body.

In Postman, when I select 'binary', it gives me an option to choose a file to use.

So I select a file to test and hit the Send button.

But I just get this back:

{
    "type": "https://tools.ietf.org/html/rfc7231#section-6.5.13",
    "title": "Unsupported Media Type",
    "status": 415,
    "traceId": "|dc4efc3f-45ae830112e6f778."
}

What could I be doing wrong?

Thanks!

Debug this action when you are sending data via postman and check if Request.Body contains your data. If it has then just remove parameter and parse it manually. — Krystian Sitek, Jun 09 '20 at 19:08

score 1 · Answer 1 · answered Jun 09 '20 at 20:57

1

Try using [FromForm] not [FromBody]. It should work.

answered Jun 09 '20 at 20:57

RussianPupok Pupok

31
4

Hi thanks, but the application/game that will be using this API does not have a form. – SkyeBoniwell Jun 11 '20 at 12:45

score 1 · Answer 2 · answered Jun 11 '20 at 01:44

1

Usually, files can be submitted through the form, and receive the it in the form of [FromForm]IFormFile in the background. Since you need to use [FromBody], you can first encode the file into a base64 string, pass it to the background as json format, and then decode it and do the upload.

Encode:

Byte[] bytes = File.ReadAllBytes("path");
String file = Convert.ToBase64String(bytes);

Decode:

Byte[] bytes = Convert.FromBase64String(b64Str);
File.WriteAllBytes(path, bytes);

answered Jun 11 '20 at 01:44

mj1313

7,930
2
12
32

thanks! Would this go inside my using filestream statement? – SkyeBoniwell Jun 11 '20 at 12:46
Also, what do you mean "pass it to the background" ? thanks – SkyeBoniwell Jun 11 '20 at 13:13
@SkyeBoniwell You can refer to this [link](https://stackoverflow.com/a/39394266/11965297), and the background here means your api controller. – mj1313 Jun 12 '20 at 06:55

NetCore API controller will not accept files uploaded using FromBody

2 Answers2