How do I pass the content type of a file to Graph API in an uploadSession?

[Ghostbird]

Our system uploads files to OneDrive using the Graph API upload session. But I cannot find out how to set the correct content type. The MimeType of the resulting DriveItem is set to application/octet-stream instead of the correct image content type. Which makes sense, as I didn't tell Graph API what the content type is. I cannot find any documentation on how to pass the content type. I've seen that when doing "small file uploads" with lower-level HTTP, you can directly set the Content-Type HTTP Header. However for the large file upload API, all that is abstracted away.

How can I pass the content type correctly to Graph API when I upload the file using an UploadSession?

[andrueastman]

Thanks for raising this @Ghostbird

Any chance you've come across the docs here? The should have info how to do large file uploads using the SDKs.

https://learn.microsoft.com/en-us/graph/sdks/large-file-upload?tabs=csharp

[Ghostbird]

Of course, however, there's nothing there about the content type.

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On 29 August 2024 15:41:02 UTC, Andrew Omondi ***@***.***> wrote: Thanks for raising this @Ghostbird Any chance you've come across the docs here? The should have info how to do large file uploads using the SDKs. https://learn.microsoft.com/en-us/graph/sdks/large-file-upload?tabs=csharp -- Reply to this email directly or view it on GitHub: #2646 (comment) You are receiving this because you were mentioned. Message ID: ***@***.***>

[Ghostbird]

Whelp. I think Microsoft Graph is spectacularly unsuitable for storing files.

I'm not doing anything special. I'm just uploading an image. But the content type returned is "application/octet-stream" which is spectacularly useless.

The File documentation states

The MIME type for the file. This is determined by logic on the server and might not be the value provided when the file was uploaded. Read-only.

Read-only is evident when trying to update it with the correct content type yields:

Status Code: BadRequest
Microsoft.Graph.ServiceException: Code: notSupported
Message: Operation not supported

WHY would anyone design a file storage mechanism in such a way that it explicitly warps the file metadata into something incorrect when storing a file? This seems utterly mental to me!

This guarantees that if I ever have to choose a file storage for a project, it will NOT be through Microsoft Graph.

[Ghostbird]

Note: It depends on the actual file. It seems that Graph API likes to guess the content type based on the file name. That would be fine if no content type was provided. It would be doable if I could correct it myself later. But it's bananas that it's unchangeable.

[Ghostbird]

Even worse, it's unpredictable. Behaviour is different based on which specific MicrosoftGraphDrive I'm writing the files to. That SHOULD have been abstracted away correctly in the Graph API layer.