inessential by Brent Simmons

OPML File Type on Macs

I was fixing a bug in OmniOutliner where it wouldn’t open a file with an uppercase .OPML suffix. I did some digging, and the fix was to register the app as handling the file type.

Which upset me. I’ll explain.

OPML — Outline Processor Markup Language — was invented in 2000 by Dave Winer at UserLand Software. It’s not Apple’s format, and the correct file type is org.opml.opml.

I was working for Dave at the time. Some time after Dave wrote the first OPML reading and writing code, I ported it to C. Later, when I was working on NetNewsWire, in 2002, I wrote what may have been the first Objective-C code for reading and writing OPML. And today I work on OmniOutliner, which supports OPML, and I’ve published an open source OPML parser.

So I know OPML. After Dave, I may have worked with this format more than anyone else in the world.

This file type redefinition not only created a bug that I had to figure out and fix, it also demonstrated disrespect. I suspect it was entirely thoughtless — but, well, that’s still bad.

Radar forthcoming.

Update: Bug filed: rdar://29888756.