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Re: MIME's "Content-Disposition" Header

1995-01-18 10:58:52
I propose that a new
parameter, Portable-Filename, is introduced. Its values would
have a restricted syntax. It could be used together with the
Filename parameter like in this example:

Content-Type: image/gif
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
Content-Description: A table showing all glyphs of the main
 runic font Futhark A, in 300 dpi resolution.

I actually think this is a bad idea. Generating the portable filename is
going to require one of two things to happen: (a) The sending client is
going to have to use some algorithm to generate a portable filename to use
if the real filename doesn't work on the machine, or (b) the user will have
to choose the filename. Choice (b) is usually considered too burdensome, so
the MUA is going to try to come up with a portable name on its own. Given
that, I don't see why you'd want to put that kind of functionality into the
client to perform when it is always the recipient who has to determine its
own limitations. A recipient is much more likely to come up with a useful
name for its purposes (given any full filename by the client) than a client
will be able to make that decision for the recipient. For instance, if I
sent from my Macintosh:

Content-Type: image/gif
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
        filename="Pete's Favorite Flower"

Neither a UNIX client nor a DOS client is going to be terribly happy, but a
UNIX client might decide that it can use the descriptive:


whereas a DOS client might have to settle for "PETESFAV.GIF". Other systems
might make different decisions about the best filename given what the
sender sent. If instead the client decides on a portable name, the UNIX box
might decide "I can't use the real name, so I best use the portable one."
Then, of course, if the UNIX recipient has any brains at all, it might also
decide, "Gee, all GIF files on my system have to end with lowercase '.gif',
and this one ends in '.GIF'. I guess I should add that."

It seems to me that if you want to make decisions about a good filename for
a recipient, the recipient should be the one deciding, not the sender.
Especially since most recipients have some smarts about such things anyway.

I find this argument quite compelling. I no longer think that the
generation of a portable filename by the sender is viable.