Access macOS Photo Library using Electron - node.js

Question

I am trying to write an Electron application that lets users select photos from their photo library on macOS. My assumption is that the only way to access the photos without exporting them is by going into ~/Pictures/Photos Library.photoslibrary. However, when passing the file path of a photo to an <img> tag, I get net::ERR_ACCESS_DENIED error.
Is there a way to grant Electron application access to the user's photo library?

Answer 1

I've been writing code recently that accesses the PhotosLibrary. I did this by writing a native module that calls the PhotoKit API. If you go that direction there's going to be a steep learning curve as you'll likely be using Objective-C++ with the features and quirks of both C++ and Objective-C while trying to write something in JavaScript.
https://github.com/nodejs/node-addon-api
https://developer.apple.com/documentation/photokit?language=objc
With Apple's recent security features, you'll also need to somehow run your code inside of an app with the correct entitlements and values set in its Info.plist that will allow access to APIs.
In build/entitlements.mac.plist:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<!-- https://github.com/electron/electron-notarize#prerequisites -->
<key>com.apple.security.cs.allow-jit</key>
<true/>
<key>com.apple.security.cs.allow-unsigned-executable-memory</key>
<true/>
<!-- https://github.com/electron-userland/electron-builder/issues/3940 -->
<key>com.apple.security.cs.disable-library-validation</key>
<true/>
<!-- Allow app to access Photos Library using PhotoKit API -->
<key>com.apple.security.personal-information.photos-library</key>
<true/>
</dict>
</plist>
The following will be needed in your App's Info.plist:
<plist version="1.0">
<dict>
...
<key>NSPhotoLibraryUsageDescription</key>
<string>This app needs access to the photos library</string>
</dict>
</plist>
This can be done using electron-builder by adding the following value to the extendInfo extendInfo of your mac build settings in package.json.
{
...
"build": {
...
"mac": {
...
"extendInfo": {
...
"NSPhotoLibraryUsageDescription": "This app needs access to the photos library"
}
}
}
}
I hope this is gives you something to start with. Like I said above, this will come with a steep learning curve unless you're already familiar with JavaScript, native module development, Objective-C, C++ and Apple's APIs.

Answer 2

If you just need to read data from it for a one-off project, the photolibrary is really just a directory-like container around your photos, and an sqlite database for the metadata (faces, places and albums/folders). Right click-the photolibrary, show package contents, orig photos are under Masters/YYYY/MM/DD/IMG_XXXX.JPG format, and metadata is in database/photos.db, some tables you can query are RKMaster (filename/uuid of master files), RKAlbum, RKFace, RKMemory, RKPlace, RKFolder, RKVersion, RKKeyword, etc., get any free sqlite browser and you can figure out the rest.
You can also copy the .photolibrary file to Linux and scan its folder/sqlite file using pure node, you don't need any native modules to read it. Writing to it may try to fire some sqlite triggers that seem to belong to some macosx-proprietary extensions, so make backups first, try writes with extensions disabled, or just read and extract the images and metadata to some other format (raw jpeg/json files in a bucket somewhere) that are easy to collate and then (if you have to), reverse the process and write out to another photolibrary file once you get the relation between the tables and filesystem paths inside its container.