iOS Swift 4: Get Image Format (JPG,PNG,GIF) From didFinishPickingMediaWithInfo

Question

I'm building an app that allows you to upload images from your library to the server. This server is used as essentially an image repository. For this reason, it's absolutely necessary to store it in it's original image format: Either JPG, PNG, or GIF. IE If the PNG image has transparency, that HAS to be preserved, it cannot simply be converted to a JPG.

I USED to get the image format using UIImagePickerControllerReferenceURL:

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        let selectedImage = info[UIImagePickerControllerEditedImage] as! UIImage
        let assetPath = info[UIImagePickerControllerReferenceURL] as! NSURL

        if (assetPath.absoluteString?.hasSuffix("JPG"))! {
            print("JPG")
        }
        else if (assetPath.absoluteString?.hasSuffix("PNG"))! {
            print("PNG")
        }
        else if (assetPath.absoluteString?.hasSuffix("GIF"))! {
            print("GIF")
        }
        else {
            print("Unknown")
        }

        self.dismiss(animated: true, completion: nil)

        self.showImageFieldModal(selectedImage: selectedImage)
    }

But UIImagePickerControllerReferenceURL has been deprecated in iOS11. It suggests using UIImagePickerControllerPHAsset, but that's not a URL. I'm not sure what I'm supposed to do with that as a PHAsset object...

Answer 1

In iOS11 you can use the original image url key UIImagePickerControllerImageURL and use URL resourceValues method to get its typeIdentifierKey :

if #available(iOS 11.0, *) {
    if let imageURL = info[UIImagePickerControllerImageURL] as? URL {
        print(imageURL.typeIdentifier ?? "unknown UTI")  // this will print public.jpeg or another file UTI
    }
} else {
        // Fallback on earlier versions
}

---

You can use the typeIdentifier extension from this answer to find out the fileURL type identifier:

extension URL {
    var typeIdentifier: String? {
        return (try? resourceValues(forKeys: [.typeIdentifierKey]))?.typeIdentifier
    }
}