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Re: Suggestion : New Content-Disposition parameters...

2004-07-06 16:04:00

Tanu Mutreja wrote:

I feel that few more parameters should / could also be added to the list
of content-disposition parameters. To be more precise, following
parameters related to the origin of a file should also be added i.e.

1. Source of the file creation
2. Author of the file
3. A parameter to represent if the material is copyrighted or not?
4. Version of the file

I agree with Keith's remarks posted to ietf-822.

In addition, I would point out that the first three items are already handled
within the content for some media types (e.g. application/pdf). In such cases,
inclusion of the same type of information outside of the content can lead to
one of the following problems (or a combination of the two):

1. the information is redundant, and therefore wastes some bandwidth
2. the information does not match that within the content, leading to

In cases where the content has no such provision, such information could be
provided textually by wrapping it in a multipart/mixed wrapper with the
actual content.  The information could even be given a different disposition
than the content, e.g. it could be marked for inline presentation, while the
content could be marked as "attachment".  Unfortunately, some UAs don't
handle nested MIME parts well more than a decade after MIME's introduction,
but that's another matter.

Regarding the 4th item, it's not clear whether that is meant to indicate the
version of the content (as in today's revision of the "foo" document) or the
version of the application required to read the content (as in the version of
Microsoft PowerPoint needed to read a given piece of content of media type
application/ [files generated by version 4 of MS PowerPoint
cannot be read with version 3 or earlier programs]).  The former case could
be indicated via a Content-Description field, and the latter would probably
best be handled via a media/subtype-specific parameter to the Content-Type
field, as it is an attribute of the media type rather than its disposition.
Ideally, the registrant of a media type which is anticipated to have version
issues that result in a loss of backward compatibility would make provision
for a parameter to indicate the format version ( does not
do so, incidentally).