proposal for capabilities lookup

Martin Atkins mart at
Mon Nov 21 00:33:17 PST 2005

Michael Graves wrote:
> The interesting thing here is that orienting things toward static file 
> semantics ( GET "yadis.xml" vs. CGI call) does *not* hinder the service 
> provider from serving static file requests with dynamic responses. In other 
> words, this URL:
> is *ostensibly* a static file on the server, but with straightforward changes 
> to the Apache configuration, this same URL can be served from a database or 
> other resource, rather than just feeding back a static file. "yadis.xml" may 
> not exist as a discrete file on any user's home directory for a given service 
> provider. It may just be synthesized on demand and spit back as the 
> appropriate file by Apache.

I keep rambling about CMSes that don't work from static files. Allow me
to briefly describe the behavior of one in particular that won't work
with your proposed scheme.

The CMS takes over the entire URL-space for a given domain, with two
* A particular "subdirectory" (as in, a prefix ending in a slash) is set
aside for static files the user has uploaded. Usually these are PDF
documents, images and the like.
* Each site template (or "skin") has its own media directory which is a
filesystem directory mapped into the URLspace for such things as
stylesheets and images.

Users have no access to put "files" anywhere except in these two
directories. They can, however, alter their site templates. This means
that they can add anything they like into the HEAD section of the
generated HTML, assuming that they don't mind it being there on every page.

For the rest of the site, the system uses URLs like:
These always end with a trailing slash. The system splits this up at the
slashes and then recursively resolves the URL "parts" one by one through
a set of lookup tables and eventually figures out what page to display
from the database.

It's not possible for users to create non-HTML documents here. It's also
not possible to create a "file" called yadis.xml, because that does not
end in a trailing slash.

This kind of thinking might well seem off-the-wall at this point, but
this does seem to be the way things are heading. With hosted weblog
services (LiveJournal being an example) and systems which provide users
with what is essentially a CMS into which they can inject their own
content (MySpace? I'm not sure, I've never actually used it), sites
based on static files are going to become less common. It's silly to
depend on it.

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