While implementing file upload using Microsoft Graph API I faced the issue that once I upload file I don't get MIME type of it. I can't send it via API as well as it's not determined automatically. I use resumable upload API:
https://dev.onedrive.com/items/upload_large_files.htm
I was thinking about determining it from the name(extension part) on my side, when I get the name of the file, but I hope there is a better way to do this with OneDrive Microsoft Graph API.