Re: Version identifier in URL

David J. Fiander (
Thu, 30 May 1996 08:35:42 -0400

> Wait, I didn't see that anyone was proposing to "standardize the
> syntax of version identifiers across all servers". After all, most
> servers don't even have versions.

I agree.  Perhaps a better way of describing _my_ motivation is
that I am attempting to develop standard techniques (I can't
really use the word methods here right now ;-)) for version
control and document management on the web.  Now, that's a very
big can of worms, all of whom are heading in different
directions, so step one is to standardise a way to refer to
version identifiers in URLs, thereby allowing servers to
advertise/export/make available (*) older revisions of pages.

What I want to standardise, in the first step is ";version=opaque
revision id".  No more, no less.  Once that's out of the way, we
can start talking about new methods for locking revisions,
checking in revisions, the semantics of the Content-Version HTTP
header, and so on.

(*) Terminology question: what does one call it when a server
finds a URL acceptable and returns a page in response to a GET on
that URL?  Is the server exporting the page?  It's certainly not
advertising it, unless there's a link to it from the outside

> Separate out the problem of
>   a) construct a URL for a previous version of a resource
>      given the current version of a resource and information
>      about the server's versioning system
>   b) determining from two URLs what their version relationship
>      might be.
> I think it's reasonable to use URL-decoration for (a) and not for (b).

I agree entirely, given the caveat that the "construction" may
not, and probably is not, possible for the client, but almost
certainly is for the user.  That is, given a URL, a _general
purpose_ client is not going to be able to create a versioned URL
with any hope of getting the "right" thing (of course a
special-purpose client that knows what versioning software is
running on the server can do better).  Humans on the other hand,
know exactly how versions work and can type into the "go" dialog
exactly what they want.

- David