- From: Geoffrey Sneddon <foolistbar@googlemail.com>
- Date: Fri, 29 Feb 2008 16:43:42 +0000
- To: Julian Reschke <julian.reschke@gmx.de>
- Cc: James Graham <jg307@cam.ac.uk>, WHATWG List <whatwg@whatwg.org>, "public-html@w3.org WG" <public-html@w3.org>
On 29 Feb 2008, at 16:33, Julian Reschke wrote: > Geoffrey Sneddon wrote: >>>> It seems like the HTTP spec should define how to handle that, but >>>> the HTTP working group has indicated a desire to not specify >>>> error handling behaviour, so I guess it's up to us. >>>> IE and Safari use the first one, Firefox and Opera use the last >>>> one. I guess we'll use the first one. >>> >>> Isn't the fact that FF and IE disagree here an indication that >>> this doesn't need to be specified? >> Things aren't specified well enough until I can write an HTTP UA >> that can work in the real world (which, as someone dealing with >> feeds, I can tell you need without question support for content- >> type sniffing) from reading specifications without having to >> reverse-engineer anything. >> ... > > Doesn't seem to apply to this case. > > A duplicate Content-Type header response indicates that the response > is invalid. And guess what? Users don't like error messages. I want to know how to deal with it without having to look elsewhere (from the spec). > Apparently, most browsers accept the response anyway, some of which > picking the first value, others the second. Both behaviors seem to > be acceptable to users. > > So there's nothing you *need* to reverse engineer in this case. A page (<http://www.toledoblade.com/apps/pbcs.dll/section?Category=RSS01&mime=XML >) that I came across recently had: Content-Type: XML Content-Type: text/XML Using the first would break badly. I guess it seems to work because of content-type sniffing on an unknown (and invalid) header (or, as many feed readers do, totally ignoring it, with the exception of any charset parameter). Without content-type sniffing, that HTML 5 now allows, you need the last. But as James says: how do I know that which behaviour I choose doesn't matter until I reverse engineer browsers to discover that? -- Geoffrey Sneddon <http://gsnedders.com/>
Received on Friday, 29 February 2008 16:44:09 UTC