Using MimeMapping in ASP.NET Core

I'm trying to move my old mvc5 project to asp net core. Old code was:

public string ContentType
{
    get
    {
        if (!string.IsNullOrEmpty(FileName))
            return MimeMapping.GetMimeMapping(FileName);
        return null;
    }
}

Error is

The name 'MimeMapping' does not exist in the current context

The following code should work:

string contentType;
new FileExtensionContentTypeProvider().TryGetContentType(FileName, out contentType);
return contentType ?? "application/octet-stream";

There is a NuGet package MimeTypes which works with .Net Core projects as an alternative to FileExtensionContentTypeProvider. I'm not aware of any other mime-type resolver package, which works with .Net Core (at least so far).

The usage is simple:

string fileName = "trial.jpg";
string mime = MimeKit.MimeTypes.GetMimeType(fileName);

System.Web is not moved to .NetCore because it relies too much on API's that are platform specific. You could take a look at Microsoft reference source:

https://github.com/Microsoft/referencesource/blob/master/System.Web/MimeMapping.cs

The code is subject to a MIT license.