overriding Mac app file associations via CFBundleDocumentTypes in info.plist

Question

I develop a Mac app that saves and loads files of a unique type. The type is properly declared in the info.plist under CFBundleDocumentTypes, listed as LSHandlerRank: Owner and CFBundleTypeRole: Editor. I am releasing a new version of my app and I would like that if users who already have a previous version of my app on their machine install the new version but keep the old version also installed, the new version automatically takes over the file association for this type from the old version of the app. But the default OS behavior seems to be to grant the earliest installed app associated with a file type to be it's permanent owner unless the user manually changes it. I know that the command line tool duti can make association changes, and also the system file com.apple.LaunchServices.plist can be edited, but these don't seem like the best or most reliable way to go about this programmatically from an app. Is there any "right"/Apple-sanctioned way to do what I want?

Answer 1

The official, Apple-sanctioned way for an application to set the default application for a file type is probably to use their provided LSSetDefaultRoleHandlerForContentType function. This function sets the values stored in LaunchServices.

Here is the limited official documentation on how to use this API in Objective-C and Swift.

There doesn't appear to be any way to do this via Info.plist, as the first application get's set as the user preferred application. The user must change their preferred application, which you can facilitate with the above API.