iphone - iOS 8 Photos framework. Access photo metadata

Question

I'm looking at replacing ALAssetsLibrary with Photos framework in my app.

I can retrieve photos, collections, and asset sources just fine (even write them back out), but don't see anywhere to access the metadata of the photos (the dictionaries such as {Exif}, {TIFF}, {GPS}, etc...).

ALAssetsLibrary has a way. UIImagePickerController has a way. Photos must have a way too.

I see that PHAsset has a location property which will do for the GPS dictionary, but I'm looking to access all of the metadata which include faces, orientation, exposure, ISO, and tons more.

Currently apple is at beta 2. Perhaps there are more APIs to come ?

UPDATE

There is no official way to do this using only Photos APIs.

However you can read the metadata after you download the image data. There are a couple of methods to do this using either PHImageManager or PHContentEditingInput.

The PHContentEditingInput method required less code and doesn't require you to import ImageIO. I've wrapped it up in a PHAsset category.

Answer 1

If you request a content editing input, you can get the full image as a CIImage, and CIImage has a property titled properties which is a dictionary containing the image metadata.

Sample Swift Code:

let options = PHContentEditingInputRequestOptions()
options.networkAccessAllowed = true //download asset metadata from iCloud if needed

asset.requestContentEditingInputWithOptions(options) { (contentEditingInput: PHContentEditingInput?, _) -> Void in
    let fullImage = CIImage(contentsOfURL: contentEditingInput!.fullSizeImageURL)

    print(fullImage.properties)
}

Sample Objective-C Code:

PHContentEditingInputRequestOptions *options = [[PHContentEditingInputRequestOptions alloc] init];
options.networkAccessAllowed = YES; //download asset metadata from iCloud if needed

[asset requestContentEditingInputWithOptions:options completionHandler:^(PHContentEditingInput *contentEditingInput, NSDictionary *info) {
    CIImage *fullImage = [CIImage imageWithContentsOfURL:contentEditingInput.fullSizeImageURL];

    NSLog(@"%@", fullImage.properties.description);
}];

You'll get the desired {Exif}, {TIFF}, {GPS}, etc dictionaries.