- From: Adrien de Croy <adrien@qbik.com>
- Date: Thu, 02 Apr 2009 10:19:49 +1300
- To: HTTP Working Group <ietf-http-wg@w3.org>
some servers sent certain mime types as a default if the actual mime type was unknown or there was no mapping for the file extension. I don't know how common this is any more, but it certainly created a need for sniffing, since the "authoritative" mime type was a bad guess. In fact the concept of what constitutes an authoritative mime type is a bit tenuous. if it's a web server guess, then what makes it any better than a client's guess. frequently it will be worse. maybe we need a weakness indicator for the content type field, e.g Content-Type: W/"application/octet-stream" or Content-Type: application/octet-stream ; certainty = random-guess meaning "we think it might be application/octet-stream" IOW, maybe an indication of whether to sniff or not shouldn't be another header, but a parameter of the Content-Type header. Then one could indicate the source/strength of the mime type, e.g. * explicitly set by management interface * explicitly set by CGI / script * guessed by file extension * guessed by sniffing at server * guessed by sniffing at intermediary * pulled out of a hat Adrien Adam Barth wrote: > On Wed, Apr 1, 2009 at 9:10 AM, Mark Baker <mark@coactus.com> wrote: > >> On Wed, Apr 1, 2009 at 12:01 PM, Adam Barth <w3c@adambarth.com> wrote: >> >>> The current HTTP spec contains a requirement that contradicts this >>> widespread practice. It seems we should update this part of the spec >>> to reflect reality (and, perhaps, nudge reality into a slightly better >>> equilibrium). >>> >> Which requirement is that? >> > > >From http://www.w3.org/Protocols/rfc2616/rfc2616-sec7.html#sec7.2.1 > > "If and only if the media type is not given by a Content-Type field, > the recipient MAY attempt to guess the media type via inspection of > its content and/or the name extension(s) of the URI used to identify > the resource." > > For example, user agents also need to sniff HTTP responses with a > Content-Type of */* in order to be compatible with existing Web > content. > > Adam > > -- Adrien de Croy - WinGate Proxy Server - http://www.wingate.com
Received on Wednesday, 1 April 2009 21:17:34 UTC