How to define a File response for OpenApi in AspNetCore

Question

I´m writing a Controllermethod in AspNet Core 5 that should return a file as stream.

[HttpGet]
[Route("/docs/{id}")]
[ProducesResponseType(StatusCodes.Status200OK)]
public async Task<IActionResult> GetDocumentAsync([FromRoute][Required] Guid? id)
{
    var (stream, fileExtension) = await _dmsService.OpenDocumentAsync(id.Value, FileAccess.Read);
    return File(
        stream,
        contentType: "application/octet-stream",
        fileDownloadName: $"{id}{fileExtension}",
        enableRangeProcessing: false);
}

So far everything works but now I want to document the API.
Im using Swashbuckle.AspNetCore 6.1.4 to generate the OpenAPI description which than should be used to generate a client.

When I return some object it´s easy by using ActionResult<T> as return type.
But how can I tell Swashbuckle that the response is a stream?

Answer 1

[ProducesResponseType(typeof(FileStreamResult), (int)HttpStatusCode.OK)]