Re: Version identifier in URL

David J. Fiander (
Fri, 07 Jun 1996 08:51:14 -0400

> 5) GET /path/resource HTTP/1.0
>    Content-version: x
> proposed by Kenji Takahashi and generally criticized for requiring
> versioning-aware clients and for being impossible to specify in an anchor.

I never criticised this option (much).  I <em>did</em> criticise
Kenji's suggestion that this is the only way that should be
available.  I think that HTTP headers are quite appropriate, as
long as there's also a way to create a link to a version.

> - The slash is already reserved for hierarchies. Hierarchies of different
> origin can be piled by juxtaposing the path name. This can't be said for
> the other proposed schemas:
>       ftp://host/dir/file;A;version=x
> or
>       wais://host/database/c/A;B;version=x
> while being outside of the scope of a discussion on HTTP, look pretty silly
> anyway and would make the ftp or wais access to these resources impossible
> or completely different.

Umm... how would the ftp server (which was written by a
completely different people and doesn't know a URL from a hole in
the ground) deal with ftp://host/dir/projectX/1.5/Mac/French/file.c
given that, more than likely, "projectX" is the name of a
configuration file, 1.5 specifies a revision in a VCS file, and
"Mac" and "French" are, respectively, a compile-time option and a
run-time locale specification?

I think that this particular argument is specious.

> Finally, I find slashes easier to read than adding yet another decoration.
> Suppose I want to access  anchor "chapter1" of the document described by
> author="bill" and name="foo" as retrieved by version Y of the search engine
> "application". For instance, what would be the right syntax in this case?
>       http://host/cgi-bin/application;version=Y?author=bill+name=foo#chapter1
>       http://host/cgi-bin/application?author=bill+name=foo;version=Y#chapter1
>       http://host/cgi-bin/application?author=bill+name=foo#chapter1;version=1
> Compare to the simple:
>       http://host/cgi-bin/application/Y?author=bill+name=foo#chapter1

Since the HTTP URL syntax states that URL parameters preceed
queries, the correct syntax would be


That is, your first option.

> - I don't know if there exists a file system in which a file and a
> directory can have exactly the same name, and are distinguished by the fact
> that one is a directory and the other is a file. I mean, if it were
> possible for a directory to have both a file and a directory called
> file.html, then the URL:
>       http://host/dir/file.html/1.5
> would be ambiguous. If there is such a perverted file system, I will
> withdraw my points and leave to become a goatherd in Sardinia (Italy).

Well the Thoth operating system from the university of waterloo
allowed a node in the filesystem to contain both data and links
to subnodes.  So a "directory" could be opened and read as a
file, or it could be traversed to find subdirs.  I understand
that the weather in Italy is very nice ;-)

- David