How does file association work?

[britespaak]

Hi, how does MacOS X find out which programmes open which kinds of files? I know there's a file in each package that tells the OS what it can do, but how does MacOS read it? Does it do a full system scan every so often, or once you browse the folder does it read the application info?

Thanks,
BriteSpaak

 

[duff]

I'm not sure how it works, but i do know how to change the default file association, select the file, press Command+I (Apple+I), then under "Open With", select which application you want it to open by default, or add a new one, i'm not sure how to remove it from the list though.

 

[Mikuro]

OS X maintains a database, and updates its entry for each application whenever that application is moved. So when you install an application, it's added to the database. When you delete it, it's removed. And every time you move it, it's updated.

I often tweak my applications to allow them to accept dropped files of types they don't normally accept. One example is QuickTime Player — I edited it so I can drop WMVs onto it now that I have Flip4Mac's WMV player for QT. But the change doesn't "take" until I move the QuickTime Player application to a different folder. As soon as I move it & move it back, my new settings take effect.