Share images from Dropbox/Google Photos into Expo app?

[isaachinman]

I may have reached the point where I have to detach my Expo project. I need to add my app to the drawer of “sharing options” when choosing to share an asset type from inside a third party library.

From inside the camera roll app, for example, I could click an image, then click share, and get something like:

This would launch the Expo app and run some handler function.

I found this issue on GitHub and commented:

https://github.com/expo/expo/issues/48#issuecomment-373375453

One of the maintainers has stated: “There is no native share extension API”, so I assume this is pretty much a case-closed issue.

I am wondering two things:

1. Has anyone run into this before, and found a way around it without detaching?
2. How do you do this in vanilla RN, anyways (not the best question for this forum)?

Thanks!

[bacon]

I’m assuming you’ve seen the docs on adding this feature: Technical Q&A QA1587: How do I get my application to show up in the Open in... menu. in which Apple walks you through how to get a UTI ()

---

If you wanna play with my thoughts, here they are:

I’ll only cover iOS as I’ve only ever done this on native iOS.

You mostly need access to the info.plist - supported
Then add support for your favorite file types!
info.plist

<key>CFBundleDocumentTypes</key>
<array>
    <dict>
        <key>CFBundleTypeIconFiles</key>
        <array>
            <string>Document-molecules-320.png</string>
            <string>Document-molecules-64.png</string>
        </array>
        <key>CFBundleTypeName</key>
        <string>Molecules Structure File</string>
        <key>CFBundleTypeRole</key>
        <string>Viewer</string>
        <key>LSHandlerRank</key>
        <string>Owner</string>
        <key>LSItemContentTypes</key>
        <array>
            <string>com.sunsetlakesoftware.molecules.pdb</string>
            <string>org.gnu.gnu-zip-archive</string>
        </array>
    </dict>
</array>
<key>UTExportedTypeDeclarations</key>
<array>
    <dict>
        <key>UTTypeConformsTo</key>
        <array>
            <string>public.plain-text</string>
            <string>public.text</string>
        </array>
        <key>UTTypeDescription</key>
        <string>Molecules Structure File</string>
        <key>UTTypeIdentifier</key>
        <string>com.sunsetlakesoftware.molecules.pdb</string>
        <key>UTTypeTagSpecification</key>
        <dict>
            <key>public.filename-extension</key>
            <string>pdb</string>
            <key>public.mime-type</key>
            <string>chemical/x-pdb</string>
        </dict>
    </dict>
</array>

Which maybe translates to this:

app.json

{
  "ios": {
    "infoPlist": {
      "CFBundleDocumentTypes": [
        {
           "CFBundleTypeIconFiles": [
            "Document-molecules-320.png",
            "Document-molecules-64.png"
          ],
          "CFBundleTypeName": "Molecules Structure File",
          "CFBundleTypeRole": "Viewer",
          "LSHandlerRank": "Owner",
          "LSItemContentTypes": [
            "com.sunsetlakesoftware.molecules.pdb",
            "org.gnu.gnu-zip-archive"
          ],
        }
      ],
      "UTExportedTypeDeclarations": [
        {
          "UTTypeConformsTo": [
            "public.plain-text",
            "public.text"
          ],
          "UTTypeDescription": "Molecules Structure File",
          "UTTypeIdentifier": "com.sunsetlakesoftware.molecules.pdb",
          "UTTypeTagSpecification": {
            "public.filename-extension": "pbd",
            "public.mime-type": "chemical/x-pdb"
          }
        },
      ]
    }
  }
}

LSItemContentTypes : is a pain so maybe experiment with this in a native project.
CFBundleTypeIconFiles : I have no clue how we’d do this one but maybe a script or something can compile a local image asset.

Finally when the user opens your app, you need to get the file - not sure about this one.
This is done through an AppDelegate method called application:openURL:sourceApplication:annotation
It looks like we do something with this but I’m not sure where you access that. (I didn’t really look )

If also looks like depending on the state of the app, the file might be open and passed to application:didFinishLaunchingWithOptions instead!

This is also made confusing by the addition of the files app in ios - I’m not sure how it plays into this exact feature but let’s say it did you would add this key to your app.json ios.infoPlist.UIFileSharingEnabled: true

Anyways, this is a tricky topic that is very platform specific so Expo probably won’t support soon… probs detach.