Re: Charset mandatory in unix/linux

On Sun March 12 2006 10:10, [email protected] wrote:
> 
> (cc'ing the ietf-types list since this doesn't seem like an appropriate topic
> for ietf-822)
[this response to types, cc to 822, Reply-To set to types]

[Jacob Palme wrote] 
> > The charset parameter is mandatory in the MIME content-type
> > attribute.
> 
> Actually, I don't know of a single case where this is true. All media type
> pararameters are either type or subtype specific, so there is no general rule
> that applies to all charset parameters. Nevertheless, the charset parameters
> that attach to the text top-level type are optional, as is the charset
> parameter on application/xml.

What about text/directory and application/shf+xml (RFCs 2425 and
4194 respectively)?

RFC 2425:

5.3.  Required parameters

   Required parameters: charset

RFC 4194:

9.  IANA Considerations

   This section contains the registration information for the MIME type
   to SHF.  The media type has been chosen to comply with the guidelines
   in [4].

   o  Registration: application/shf+xml
   o  MIME media type name: application
   o  MIME subtype name: shf+xml
   o  Required parameters: charset

   Required parameters: charset

   This parameter must exist and must be set to "UTF-8".  No other
   character sets are allowed for transporting SHF data.  The character
   set designator MUST be uppercase.

[so in the latter case, the parameter is mandatory but conveys no
useful information as the charset is fixed, i.e. known a priori for
each instance of the media type, rather than variable...
4194 also conflicts with established usage of charset parameter
values as specified in RFC 2046: "Unlike some other parameter values,
the values of the charset parameter are NOT case sensitive" (That's
for text, but having case-sensitivity of the values FOR A GIVEN
PARAMETER ATTRIBUTE vary with type/subtype greatly complicates
parsing).  Sigh...]