iOS Swift - Get mime type from data-CodePudding

I'm using the PhotosPicker library to select either an image or a video and put it into data:

@State private var selectedImageData: Data? = nil

and I need to find out what exactly was selected.

All the answers I've found was about how to retrieve the meme type from a file using the path, but I don't get the file path using PhotosPicker.

I've found this somewhere:

extension Data {
    private static let mimeTypeSignatures: [UInt8 : String] = [
        0xFF : "image/jpeg",
        0x89 : "image/png",
        0x47 : "image/gif",
        0x49 : "image/tiff",
        0x4D : "image/tiff",
        0x25 : "application/pdf",
        0xD0 : "application/vnd",
        0x46 : "text/plain",
        ]

    var mimeType: String {
        var c: UInt8 = 0
        copyBytes(to: &c, count: 1)
        return Data.mimeTypeSignatures[c] ?? "application/octet-stream"
    }
}

and it works but it's incomplete, I also need mp4, mov and just as many as possible

CodePudding user response：

A quick research on Google with "mime types hexadecimal signatures" would give you this or this, for example...

CodePudding user response：

You can use the Signature re-using the code here

After copy-pasting the logic and adding the cases for tiff, vnd or text/plain, you will end up with this logic:

enum ImageFormat {
    case gif, jpg, png, vnd, tiff, unknown
}
if let data = someData {
    switch data.format() {
    case .jpg, .png, .gif:
        print ("Formats supported by Swift. Yihaaa")
    case .tiff:
        print ("Do some fancy decoding")
    case .pdf:
        print ("Read as a file")
    case .unknown:
        print ("Treat this data differently")
    }
}

If you do the comparison using a String, make sure to decode using . isoLatin1. If you compare the bytes using the keys inside your mimeTypeSignatures, then no need to. I only personally found it more readable to use Strings. It was helpful for decoding and to add tests.

CodePudding user response：

I've found this library:

https://github.com/sendyhalim/Swime

and it works perfectly