Support returning ph:// from MediaLibrary APIs

Summary

On iOS Assets Library API is depreacted: https://developer.apple.com/documentation/assetslibrary. The MediaLibrary still uses the old assets-library:// schema. It is incompatible with a few APIs like the sharing API and the FaceDetection API.

Found this comment here that alerted me to that: https://github.com/react-native-cameraroll/react-native-cameraroll/blob/master/ios/RNCAssetsLibraryRequestHandler.m#L68.

After a Twitter conversation we found these lines responsible: https://github.com/expo/expo/blob/fffbdb3161449764087dfa6d555ad1f88eb86dfe/packages/expo-media-library/ios/EXMediaLibrary/EXMediaLibrary.m#L920-L926

I was quite confused about it as you can see here: https://stackoverflow.com/questions/67422493/getting-a-filesystem-uri-from-assets-in-expo-rn.

The only workaround I found from the JS API was to copy assets to a cache directory. This is less than ideal as it slows things down quite a bit.

Managed or bare workflow? If you have ios/ or android/ directories in your project, the answer is bare!

managed

What platform(s) does this occur on?

iOS

SDK Version (managed workflow only)

41.0

Environment

N/A

Reproducible demo or steps to reproduce from a blank project

N/A

[ajsmth]

hey there - I’ve been looking into this issue a bit today - I think the method you might want to use here is MediaLibrary.getAssetInfoAsync(asset) which will return a localUri containing the file:// url that can be used with other APIs. This method obtains a local image url via PHAsset.requestContentEditingInputWithOptions async block

An alternative, as you have noted in SO, would be using something like PHImageManager requestImageDataForAsset after obtaining the PHAsset - although this is not done by the MediaLibrary module so you’d have to write your own implementation for that.

In either case, updating the url here does not immediately solve any integration issues that you’ve described, as most of these APIs require the file:// localUri from a PHAsset, something that needs to be asynchronously fetched one way or another. That being said I think it’s safe to update the asset-library:// to ph:// url and I’ll try and get this into SDK 43

In the meantime, the an asset.id can be used to generate the same ph:// url like so:

function getPhotoKitUrl(asset) {
   return `ph://${asset.id.split("/")[0]}`
}

[StampixSMO]

I ended up just rewriting the asset-library:// URIs to ph:// URIs by grabbing the ID from the former’s query parameters & appending it to the latter.

I did have to install an SDWebImage plugin to support ph:// URIs though.