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Review of Content-Encoding: value token

From: Carine Bournez <carine@w3.org>
Date: Wed, 21 Jan 2009 14:13:32 -0500
To: ietf-http-wg@w3.org
Message-ID: <20090121191332.GA14408@homer.w3.org>


Dear HTTPbis Working Group,

The Efficient XML Interchange (EXI) Working Group is seeking advice and 
review of a proposal for a new registered HTTP content coding token 
called "exi". 

The EXI Working Group has discussed the content type management issue and
is suggesting to use a Content-Encoding, whenever possible, in order
to retain the original XML or XML-based media type (e.g. xhtml, rdf,
svg...). We also register a fallback "application/exi" media type, for 
the protocols that have no Content-Encoding capability.

The EXI format specification is currently a Last Call WD [1]
The following text is the relevant part of the EXI specification 
from current editor's draft. 
(Note that the second paragraph has been added after discussion with 
the W3C Technical Archictecture Group at the November 2008 technical
plenary meeting).

-------------------------
F.1 Content Coding

Protocols that support a mechanism to indicate the encoding
transformation of the data being transferred (e.g. HTTP 1.1) SHOULD use
the label "exi" (case-insensitive) to annotate the transfer or the
request of data structured as an XML Information Set to convey the
actual use of or the acceptance of EXI encoding for the interchange that
is underway.

It must be noted that the "exi" content-coding is neither universal nor
byte- or character-preserving. First, it can be applied only to XML
documents that have an XML Information Set. Second, the information that
the coding preserves is that XML Information Set, not the actual
characters comprising the document. For instance, whether single or
double quotes were used to delimit attribute values is not preserved.

-------------------------

Thank you.

[1] http://www.w3.org/TR/exi

-- 
On behalf of the EXI Working Group,
Carine Bournez -+- W3C Europe
Received on Wednesday, 21 January 2009 19:13:44 GMT

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