Subject: IPP> MOD - Syntax of 'document-format' proposal

From: [email-masked] (Ira Mcdonald x10962)
Date: Sun, 28 Sep 1997 11:38:30 PDT

Copies To:  [email-masked],
            [email-masked]

Hi Scott, Bob, et al,                         Sunday (28 September 1997)

In light of the laudable concensus at the last PWG monthly meeting on
using RFC 2184 compliant charset/language tags in values of datatypes
'text' and 'name', I have a suggestion about the 'document-format'
operation attribute.

There is an obvious conflict between IPP's need for a 'document-format'
attribute (SHOULD contain both 'charset' and 'language') and the MIME
(and RFC 822) 'Content-Type' header (MAY contain 'charset', but MUST NOT
contain 'language' - see RFC 2046, pg 6, and recent IPP email from Larry
Masinter).

I suggest the following (no doubt fractured) ABNF for IPP's attribute
(using US-ASCII to specify all section keywords and section values):

document-format-value := " type "/" subtype "
                         ";" "charset-section"
                         ";" "language-section"

; for 'type' and 'subtype', see BNF for 'Content-Type', RFC 2045, pg 12

charset-section := "charset" "="
                   <registered character set name [IANA registry]>

language-section := "language" "="
                    <registered langauge tag [RFC 1766]>

Then, there is a simple mapping to the [MIME] headers of 'Content-Type'
(including charset) and 'Content-Language', while preserving the single,
unified attribute functionality for IPP.

Cheers,
- Ira McDonald (outside consultant at Xerox)
  High North Inc
  906-494-2434

PS - Note that the URL for IANA assignments (all registries) is:
     "ftp://ftp.isi.edu/in-notes/iana/assignments/"

---

From: Larry Masinter <[email-masked]>
Date: Sun, 28 Sep 1997 15:48:50 PDT

> document-format-value := " type "/" subtype "

I think it isn't a good idea to muck with the MIME format for
Content-Type or to restrict the available parameters, or to
add another parameter for "language-selection" which doesn't
exist in MIME. If you want to describe some content, use "content-"
headers in entirity, "content-type: blah", "content-language: blah",
"Content-MD5: blah" or whatever.

document-format-description := content-header
-- 
http://www.parc.xerox.com/masinter