P3D OT: MIME type and web browsers (was Re: P3D JPS Files)

[Brian Reynolds <reynolds@xxxxxxxxx>]

David Spacey wrote:
> Dale Walsh wrote:-
> >
> >I have also provided a JPS link for each image.  It only works for
> >me using Internet Explorer on my Mac.  Netscape sees the JPS image
> >as a text file.  I wonder why?
>
> It's because Netscape are lazy programmers.  IE looks inside the
> file and spots a jpeg header, so then it knows what to do with the
> file.  Netscape sees that the filename extension (as you know, not
> normally a consideration for a Mac) is unknown to it, and defaults
> to text.
>

Actually that's wrong.  The HTTP (Hyper Text Transfer Protocol)
standard specifies that the client program (in this case the web
browser) receives the file type from the web server.  This is seen as
the Content-type header (with the value text/html for a static web
page, or image/jpeg for a normal JPEG image) in the http stream.  The
web server is supposed to get the file type from the filename
extension and a mapping file (the mime-types file (the name may change
depending on who wrote your server)).  If the client examines the
contents of the file to determine the file's type it is not following
the HTTP standard.

The person creating the webpage can add to the known mime-types by
using the .htaccess file.  This depends on server type and
configuration.  It would not surprise me if many hosting sites turn
off this feature.

> God it's *so* embarassing to praise a Micro$oft product, but I do find it
> significantly less crap than Netscape.  ;-)
>

Well it might be if that ever happened, but it hasn't happened in this
case.

-- 
Brian Reynolds                  | "Dee Dee!  Don't touch that button!"
reynolds@xxxxxxxxx              | "Oooh!"
http://www.panix.com/~reynolds  |    -- Dexter and Dee Dee
NAR# 54438                      |       "Dexter's Laboratory"


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End of PHOTO-3D Digest 3361
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