The Case Of The Missing Filetype

August 4th, 2011

Black Ink 1.4.1 is out with just a couple bug fixes, free for registered Black Ink customers. New customers may purchase via the Mac App Store or directly from the Red Sweater Store.

This release fixes an issue where scroll bars in the clue list appear awkwardly under Lion, and also addresses a pretty nasty behavior for customers who have downloaded the new version of Across Lite’s official solving app: opening puzzle files in Black Ink fails completely.

How can the simple act of downloading another app render Black Ink useless for opening files? It has to do with Apple’s file-typing system, and an evidently relatively undefined behavior when two different applications lay claim to the same file extension, but tag it as a different type.

When I released Black Ink 1.0 a few years ago, I adopted Apple’s latest file-typing system, based around Uniform Type Identifiers (UTIs). These identifiers allow developers to provide more meaningful information to the system about what a particular file type is, what file extensions it correlates with, more basic types (like text) that it might be derivative from, etc. Developers who “own” a particular file type give it a UTI

Since Black Ink works primarily as an editor of Across Lite format files, a format that was not invented here at Red Sweater, it would have been appropriate for me to adopt the owning company’s UTI when identifying the files that Black Ink knows how to work with. The problem? Litsoft, the company that created Across Lite, had for years neglected to update their software much, and had never declared a UTI type for the file format.

So I declared my own. I did it politely, using my own domain name in the UTI: I did this purposefully rather than trying to make up something on Litsoft’s behalf, so that I wouldn’t be stepping on their toes when they inevitably defined their own UTI.

In the wake of Lion’s release, that’s what Litsoft finally did. Their latest update to Across Lite declares a definitive UTI type for Across Lite puzzle files, which is fantastic! The problem is, Black Ink 1.4 knows nothing about it. To make matters worse, on some users’ systems, the very act of downloading and trying Across Lite’s changed the system’s idea of what .puz files are.

So users who simply tried out another piece of software were suddenly unable to open puzzle files in Black Ink. Not a good situation.

In Black Ink 1.4.1, the Across Lite UTI for “.puz” files is now listed as an “imported file type” for Black Ink. This means that while Black Ink is not considered the authoritative app for this type (nor should it be), the system should consider it a suitable candidate for opening and working with “.puz” files, whether it thinks they are of Across Lite’s UTI, or mine.

2 Responses to “The Case Of The Missing Filetype”

  1. Jens Ayton Says:

    It”™s “Uniform”, not “Universal”. Apple would never be that arrogant. ;-)

  2. Daniel Jalkut Says:

    @Jens – D’oh! I knew that too. Fixed!

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