W3C home > Mailing lists > Public > ietf-http-wg-old@w3.org > September to December 1995

Content Codings

From: Jean-Philippe Martin-Flatin <syj@ecmwf.int>
Date: Thu, 14 Sep 1995 10:53:14 +0100
Message-Id: <9509141053.ZM20206@helena>
To: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Based on HTTP/1.0 Internet Draft 03, I have 2 comments about Content Codings:

1) In Section 3.5, it states:

  Note: Use of program names for the identification of encoding formats
  is not desirable and should be discouraged for future encodings. Their
  use here is representative of historical practice, not good design.

My reading of this is that rather than the name of a compression program, one
should probably use the name of the underlying algorithm, e.g. LZW instead of
x-compress and LZ77 instead of x-gzip. The rationale is that 2 different
programs based on the same algorithm may uncompress the file, so the
reference to the name of a specific implementation of the algorithm is not a
good idea.

In practice, you may compile a program like Jean-Loup Gailly's gzip on
virtually all platforms, so most people use a single implementation of LZ77.
Many will know what x-gzip refers to, but few will for LZ77. So it seems
likely that most people will keep on using x-gzip even if x-lz77 is defined
by IANA in the future.

I therefore propose that the abovementioned comment be removed from the HTTP
spec.

2) In Section 3.5, it states:

  Note: For future compatibility, HTTP/1.0 applications should consider
  "gzip" and "compress" to be equivalent to "x-gzip" and "x-compress",
  respectively.

I guess the rationale is that IANA plans to register "gzip" and "compress" as
new MIME types in the near future (anyone up-to-date with IANA's plans ?). If
that's indeed the case, then I suggest to say it explicitly in this comment.
Something like:

  Note: IANA is currently considering the registration of 2 new MIME
  types: "gzip" and "compress". Therefore, for future compatibility,
  HTTP/1.0 applications should consider "gzip" and "compress" to be
  equivalent to "x-gzip" and "x-compress", respectively.

Jean-Philippe
Received on Thursday, 14 September 1995 02:57:34 EDT

This archive was generated by hypermail pre-2.1.9 : Wednesday, 24 September 2003 06:31:32 EDT