The reliance on Content-type

[Martin Atkins]

Drummond Reed wrote:
> 
> That way, if my server didn't understand application/xrd+xml mapping, and my
> short URL was http://example.com/~drummond, I'd know my YADIS login URL
> would be whatever I called my actual YADIS XRD file, i.e.:
> 
> 			http://example.com/~drummond/yadis.xml
> 
> In other words, rather than "magic filenames", just support: a) exact
> URL-to-filename mapping for those users whose whose identity servers don't
> recognize content negotation for YADIS XRD files, and b) HTTP content
> negotation for users whose identity servers do recognize
> "application/xrd+xml".
> 

The indirection through an HTML LINK allows the user to do this while
still entering the short "directory"-type URL. The "Accept" business is
just to allow the fancy sites like LiveJournal to bypass the overhead of
doing that indirection by providing a clue that the requesting client
wants an XRD rather than an HTML document.

While I'll admit that this usage is stretching the idea of content
negotiation a little, it doesn't seem to me to be that much of a
stretch. The client is simply saying "I'd prefer XRD, but I'll also take
an HTML document if you've got one".