- From: Eduardo Casais <casays@yahoo.com>
- Date: Tue, 6 Jan 2009 01:48:09 -0800 (PST)
- To: public-bpwg-ct@w3.org
I would like to comment on one specific statement made regarding the "no-transform" directive. >As of today, the directive is not respected by all the >existing content transformation proxies, and is >unfortunately (incorrectly, some would say) respected by >some gateways, preventing WML to WMLC conversion >and/or other optimizations that are useful on mobile >networks. The fact that WAP gateways strictly enforce the directive is neither unfortunate, nor incorrect: this is exactly what the HTTP standard mandates -- indeed it "is the standard way to prevent content modifications under any circumstances", including encoding to WBXML, GZIP or UUENCODE. There is also a reason why these WAP gateways operate like this. With the advent of WAP2.0, manufacturers developed some models that could parse and render both XHTML mp and WML directly from the XML source file. These terminals do not include an interpreter for the WBXML format. Application servers can then serve WML content with the "no-transform" directive to ensure that gateways do not encode the content for those phones that do not handle it. One could think that a gateway should actually determine whether to return source WML or WBXML-encoded WML depending on the "Accept" field sent by the terminal (one MIME type is for compiled WML, another for source WML), but this does not work. Every WML content is, by the standard, supposed to be encoded, and many terminals initially only provided the MIME type corresponding to source WML in their HTTP header. Devices that accept only source WML were considered an exception -- properly handled by application servers via "no-transform". E.Casais
Received on Tuesday, 6 January 2009 10:01:20 UTC