Check photoassets for matching urls - arrays

Question

I have an array of url's of images the user selected from the photo library. Is there a quick way to get those assets (they'll never be more than 5) from the photo library without iterating over all the users photos (which in my test is really slow).
Here is the code I am using now:
func loadCollectionView() {
arrImageViews.removeAll()
let options = PHFetchOptions()
//options.predicate = NSPredicate(format: "favorite == YES")
options.sortDescriptors = [
NSSortDescriptor(key: "creationDate", ascending: true)
]
let results = PHAsset.fetchAssets(with: .image, options: options)
var assets: [PHAsset] = []
results.enumerateObjects { (object, _, _) in
if let asset = object as? PHAsset {
assets.append(asset)
}
}
let manager = PHImageManager.default()
for thisAsset in assets {
thisAsset.getPHAssetURL(completionHandler: {(assetURL) in
if let strAssetURL = assetURL?.absoluteString {
if self.arrImagePaths.contains(strAssetURL) {
manager.requestImage(for: thisAsset, targetSize: CGSize(width: 80.0, height: 80.0), contentMode: .aspectFit, options: nil, resultHandler: {(thisImage, _) in
self.arrImageViews.append(UIImageView(image: thisImage))
self.cImages.reloadData()
})
}
}
})
}
}
getPHAssetURL is an extension that extracts the url from the asset.
So what I am looking for is a match between assetURL?.absoluteString and the strings in my array.

Answer 1

Having checked the docs, I think if you want to get info of only a single selected PHAsset, you can try this:
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
guard let asset = info[UIImagePickerControllerPHAsset] as? PHAsset else { return }
let localId = asset.localIdentifier
//Save this variable in your model.
}
If you have implemented multi-photo selection in a collectionview, you'd have to check their docs to see how to fetch the PHAssets for the selected media. But it should be quite easy.
Then with your var localIds: [String] you can try this:
let options = PHFetchOptions()
options.sortDescriptors = [
NSSortDescriptor(key: "creationDate", ascending: true)
]
let results = PHAsset.fetchAssets(withLocalIdentifiers: localIds, options: options)
Note that you can perform further filtering with predicates in your fetch request based on the keys here.