MIME type guessing module

MIME type guessing module

[David Thompson]

Hello Guile hackers,

Recently I've taken to writing simple web servers in Guile.  Each time I
write one I wish that core Guile came with a procedure to guess the mime
type of a file.  Such a procedure would be very useful when serving
arbitrary static files from disk.

However, I can't figure out the best way to implement it.  Here are 3
possible ways of guessing a MIME type:

1) Use a lookup table that maps file extensions to MIME types.  This is
the simplest method as it would only test file extensions.  Python does
this, see: <https://docs.python.org/2/library/mimetypes.html>

2) Use pipes to read the output of the 'file' utility.  The guessing
will be more accurate because 'file' inspects a file's contents to make
better guesses.

3) Use the FFI to call libmagic.  Same benefits as above, but better
because we can use the FFI instead of subprocesses and pipes.

2 and 3 both have the disadvantage of requiring an additional
dependency, which seems hard to justify for such a minor feature.

I wrote a simple static file server (inspired by Python's
SimpleHTTPServer) that I would like to contribute once this blocker is
resolved.

Thoughts?  Would this be useful at all?

Thanks,

-- 
David Thompson
Web Developer - Free Software Foundation - http://fsf.org
GPG Key: 0FF1D807
Support the FSF: https://fsf.org/donate

Re: MIME type guessing module

[Mike Gerwitz]

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On Wed, Dec 31, 2014 at 11:36:22 -0500, David Thompson wrote:
> Recently I've taken to writing simple web servers in Guile.  Each time I
> write one I wish that core Guile came with a procedure to guess the mime
> type of a file.  Such a procedure would be very useful when serving
> arbitrary static files from disk.

I'm paused on a guile-mime project that reads a XDG Shared MIME-Info
globs2 database[0]:

  https://gitorious.org/guile-mime

I was planning on continuing it's development shortly.  Do you agree
with that approach?

If you want to cooperate on an effort, that's fine with me.

(The database is distributed with most GNU/Linux distributions and can
be referenced with the `xdg*` commands on the system.)

[0]: http://standards.freedesktop.org/shared-mime-info-spec/shared-mime-info-spec-latest.html

- -- 
Mike Gerwitz
Free Software Hacker | GNU Maintainer
http://mikegerwitz.com
FSF Member #5804 | GPG Key ID: 0x8EE30EAB
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Re: MIME type guessing module

[Thien-Thi Nguyen]

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() David Thompson <dthompson2@worcester.edu>
() Wed, 31 Dec 2014 11:36:22 -0500

   Thoughts?  Would this be useful at all?

Well, if you use it, then it's useful, yes?  :-D
There's always room for more implementations.

Check out libextractor:

 http://www.gnu.org/software/libextractor/

See also "ttn-do magic", which is a pure-Scheme solution:

 http://www.gnuvola.org/software/ttn-do/ttn-do.html.gz#magic

The database is also "Schemey" -- sexps produced from parsing
~/.magic or other magic(5) databases.

-- 
Thien-Thi Nguyen
   GPG key: 4C807502
   (if you're human and you know it)
      read my lisp: (responsep (questions 'technical)
                               (not (via 'mailing-list)))
                     => nil

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