Re: Fake PDF

[Benoît Minisini <benoit.minisini@xxxxxxxxxxxxxxxx>]

Le 24/02/2026 à 21:03, gbWilly a écrit :
> On Tuesday, February 24th, 2026 at 18:59, Lee <t.lee.davidson@xxxxxxxxx> wrote:
> > That method queries the system mime type file at "/usr/share/mime/globs2" basically using it as a look-up table. On my system,
> > line 139 in that file is "50:application/pdf:*.pdf". So according to that file, all files with a ".pdf" extension are of type
> > "application/pdf". It is really stupid as it relies on the file extension as opposed to the file contents.
>
> Exactly, I'm glad you find it stupid as well. One of the first things I loved about coming to Linux was that file extensions didn't matter.
> The DesktopMime class is not reliable to return the TRUE MIME type of a file, but the FAKE one (that is true most of the time bit not always).
> The 'xdg-mime query file' equals the DesktopMine.FromFile output but on the command line level. Hence the screenshot to show the difference.
>
> > Simplified, DesktopMime.FromFile() looks up the file extension in "/usr/share/mime/globs2", finds that it is of type
> > "application/pdf", and returns that text. BTW, the Stat object created by the Stat() function will also falsely return
> > "application/pdf" for that fake PDF file.

What are you talking about? The 'Stat' class never returns a file type.

> > The `file` command, on the other hand, will actually look at the header content of the file to determine its actual type.
>
> Yes, that is why I'm going back to my old function based on a simple EXEC of the file command, giving me the TRUE MIME type as demonstrated in my previous post screenshot.
>
> Maybe the core Gambas should have a function to return the TRUE MIME type of a file instead of relying on the gb.desktop component
> I wonder what Benoit has to say about this matter on 'TRUE' and 'FAKE' MIME type and a proper MIME type function?

What's the problem with using the 'file' command? I don't see the need 
of reimplementing the wheel if that command exists, unless there is a 
library that implements the same algorithm than 'file'. In that case it 
could be used through a Gambas API. Otherwise, just use the 'file' 
command directly.

Regards,

--
Benoît Minisini.