Question

I want to display a message & install-button to the user if he did not yet install my drive app from Chrome Web Store.

Is there a way to tell if the app has been installed?

I can already access the list of apps, but I don’t find a way to distinguish whether the user can create files from the Drive “Create”-menu and see my file icons or not.

Answer 1

You can retrieve this information by sending an authorized GET request to the drive.about.get endpoint. The returned metadata will include a isCurrentAppInstalled attribute set to true if your app has been installed by the user:

GET https://www.googleapis.com/drive/v2/about
Authorization: Bearer *********