libfile and MIME integration

[Ian F. Darwin]

On February 27, 2003 04:00 pm, Christos Zoulas wrote:
> The next release of file is going to take a bit because I am working
> on libmagic, a small api that lets people use file(1) functionality
> programatically.

I thought this would be coming soon (I was about to suggest it otherwise).
The GNU project mkhybrid did this and called it libfile; I presume you've 
looked at their work and are using the same or similar API?

Anyway, my suggestion is on how to do a better job of merging mime 
types and textual file types, so that only a single data file needs to be 
maintained. The present scheme with types in "magic" also being present in 
magic2mime with their MIME correspondents, is not maintainable and violates 
the "information in one place only" pattern. I thought of something like 
this:

0 long 0x20 {
        abeco image data
        image/abeco
}

That is, a Struct-like syntax that includes both the standard file response as 
now, which can be continued etc., as at present, and a single line for the 
MIME type.

This has the advantage that you can maintain backwards compatible files
(either the file string field contains a { or it doesn't), and in libmagic 
we'll have both file types and mime types.

The API should also be used in Apache mod_file, to get rid of the "code re-use 
via the copy-and-paste design pattern" that is currently deployed there.

Ian