Thursday, December 14, 2006, 9:04:00 AM, Henri Sivonen wrote:
> On Dec 13, 2006, at 17:51, Mark Baker wrote: >> But >> given that an alternative exists which shouldn't break those servers, >> why not use it when there's no apparent downside? > The downside is that implementations that (quite reasonably) assume > that application/atom+xml == feed are also reasonable when they > ignore unknown media type parameters. An example would be an HTML page with rel="alternative" links pointing to a feed and an Atom Entry document. This seems quite a reasonable use-case, yet if we don't create a new MIME type, then I'd expect that all current feed reader implementations would incorrectly detect the entry document to be a feed, which would be very confusing for the user if they select the entry document, and their feed reader attempts to subscribe to the entry document. Which would either work, and they would get subscribed to a feed that doesn't update, or they'd get an error. > Given the options of a new type or a new parameter, I am +1 on the > new type. (Although in general, I don't like the proliferation of > application/*+xml types, because apps need to do root sniffing for > application/xml anyway.) Another issue with MIME parameters is that the old MIME RFCs are inconsistent about the definition of the term "media type", which can mean top-level type, top-level/sub-type, or top-level/sub-type with parameters. When Atom was being developed I asked (several times) whether Atom documents are allowed to contain parameters in places that they specify media types, and I got conflicting answers. My perception is that MIME parameters just don't work very well. Another case for a new type is browser dispatch. Operating systems tend not to use MIME types for deciding which application to use. Whilst a feed reader is a sensible application to open a feed in; an entry document should probably be opened in an editing/publishing application. This is not really possible if we use a MIME parameter to distinguish the two document types. -- Dave
