DocumentPicker isn't allowing all file types when browsing iCloud Drive locations

We’ve got an Expo app that we’re currently preparing for release and we use Expo DocumentPicker during the onboarding process. We’ve discovered that when browsing iCloud Drive locations only a subset of files/types are selectable. As far as I can tell we’ve setup everything correctly according to the Configuration.

The .keystore files we’re using (and some other file types eg. .sketch) our greyed out and unselectable, but only on iCloud Drive.

• The file we’re trying to select is a JSON document using .keystore extension.
• Everything works correctly on Android (whether using phone local locations or remote locations)
• Everything works correctly on iPhone when picking local files or from other remote locations (eg. Google Drive)
• We can pick other files from iCloud Drive (eg. images or PDF’s), they come into our app and the app has some logic to report that they’re invalid files.

Am I missing some required config? Is this a bug? Any help is much appreciated

[bkbooth]

Ok, I finally found the solution to this. I needed to declare the document types that our app can handle.

I really think this should be made clearer in the DocumentPicker docs. I went around in circles for a long time, and even when I thought I had it figured out, there were no concrete examples I could find anywhere of declaring document types in app.json. I basically had to map some iOS Info.plist XML examples into the app.json format.

It’s clearly not impossible to work it out, but it took a long time for me to work out and it’s definitely not friendly to newcomers.

For what it’s worth if anyone else stumbles across this, these are roughly what I ended up with in my app.json (You can search any of the keys to find the reference in the Apple docs to customise to your needs):

{
  "expo": {
    "ios": {
      "infoPlist": {
        "LSSupportsOpeningDocumentsInPlace": false,
        "CFBundleDocumentTypes": [
          {
            "CFBundleTypeName": "My Document",
            "CFBundleTypeRole": "None",
            "LSHandlerRank": "None",
            "LSItemContentTypes": [
              "com.MyOrg.MyApp.MyFiletype",
              "public.data"
            ]
          }
        ],
        "UTExportedTypeDeclarations": [
          {
            "UTTypeConformsTo": ["public.data"],
            "UTTypeDescription": "My File Type",
            "UTTypeIdentifier": "com.MyOrg.MyApp.MyFileType",
            "UTTypeTagSpecification": {
              "public.filename-extension": "myfile",
              "public.mime-type": "application/json"
            }
          }
        ]
      }
    }
  }
}

[omerg]

@bkbooth The above sample worked perfectly on iOS, huge thanks for sharing. Have you found the equivalent solution for Android as well, so that it is possible to narrow down the available extensions instead of using */*?