Additional comments on image/svg+xml

Alexey Melnikov alexey.melnikov at isode.com
Thu Sep 2 15:03:51 CEST 2010


[Resending, as it looks like my original message didn't make it.]

Chris,
The latest version of the registration is an improvement.

However based on our earlier private discussion I've decided to ask for
some additional feedback regarding associating both XML and GZIPed
version of the same format with a single media type. Below are some
comments received from email experts during YAM WG meeting in Maastricht:

MIME experts think that using +xml for gzipped material is a really bad
idea, and that having two extensions for one MIME type, with different
semantics, and with a dependency on transfer-encoding, is a bad idea.
This looks like MIME type sniffing and MIME media types were explicitly
designed to avoid this.

The cleanest way to fix this (without having a long debate about what is
correct and what is not according to MIME spec) is to have 2 separate
MIME type registrations (one for XML and one for gzipped version), each
using own file extension.

Additionally Mark Nottingham pointed out that the following text is not 
correct:

  SVG documents may be transmitted in compressed form using gzip
  compression. For systems which employ MIME-like mechanisms, such as
  HTTP, this is indicated by the Content-Transfer-Encoding header; for
  systems which do not, such as direct filesystem access, this is
  indicated by the filename extension and by the Macintosh File Type
  Codes.

because Content-Transfer-Encoding header field is not used in HTTP.




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