Sharing Video PHAsset via UIActivityController - ios

Question

I am trying to share video PHAsset via UIActivityController using requestAVAsset. This works with Messaging, but not with AirDrop, indicating as 'Failed'.
PHCachingImageManager.default().requestAVAsset(forVideo: asset, options: nil, resultHandler:
{ (givenAsset, audioMix, info) in
let videoAsset = givenAsset as! AVURLAsset
let videoURL = videoAsset.url
DispatchQueue.main.async {
let activityViewController = UIActivityViewController(
activityItems: [videoURL],
applicationActivities: nil)
activityViewController.excludedActivityTypes = [UIActivityType.saveToCameraRoll]
if let popoverPresentationController = activityViewController.popoverPresentationController {
popoverPresentationController.barButtonItem = (sender)
}
self.present(activityViewController, animated: true, completion: nil)
}
})
This seems to properly put up UIActivityController and only work with certain activities:
Messaging - ✔️Works, properly exports video.
AirDrop - ✖️Shows "Failed"
Dropbox - ✖️Puts up the proper Dropbox View, yet says "Unknown error occurred"

Answer 1

I've run into similarly odd behavior when working with PHAssets. My guess is this is a (purposely) undocumented security/sandboxing restriction.
I was able to work around this problem by copying the underlying file to a user directory, and then performing the operation on the copied file.
I did this in a loop. Occasionally, the copy fails with a vague file permissions error. When it does, I retry it after a few seconds (using DispatchQueue.main.asyncAfter). Eventually, it works!