MacOS Get default application for file type

Question

I am working on a Mac app. I ultimately want to use default app icons within my app. From the Info.plist and the Resource folder of an app I can get the .icns file and convert that to the image format I need. But I need to know the default application associated with the particular file extension, if any.

So how to get the default application that the system currently associates with a given file extension?

Answer 1

Don't go digging in other apps' bundles. It's always best to work at the level of abstraction that suits the question you want to ask. If you want to get the icon that the Finder (or a Mail attachment, etc) would display for a file of a particular type, use the NSWorkspace iconForFileType: method.

Answer 2

I think what you're looking for is part of the OSX Launch Services: LSCopyDefaultApplicationURLForContentType API. This returns the info on apps that can open specific Uniform Type Identifiers. There's also a similar API called LSCopyDefaultApplicationURLForURL to check which app opens a specific known file.