Re: WebDAV or something better? -- WebDAV (RFC2518) + DeltaV

["Bryan J. Smith" <b.j.smith@ieee.org>]

Ken Keefe wrote:  
> I am quickly finishing up a book on Apache 2 and it got to a section
> on publishing extensions and methods. The book talked about DAV for
> quite some time. It appears to me that DAV is like CVS, but for
> documents. Is that a correct assessment?

Not exactly, but it is one application.

The HTTP (Hypertext Transfer Protocol) powers more than just the web.
Many new protocols, like IPP (Internet Printing Protocol) supported by
CUPS (Common UNIX Printing System) and newer Windows releases also use
HTTP.  This is because HTTP version 1.1 (HTTP/1.1) includes the ability
to upload resources as well as download them.

WebDAV was the eventual standard (beginning with RFC2518*) that formed
out of the "Distributed Authoring" extension of HTTP.  In other words,
the ability for web content authors to directly upload files to the
server via the HTTP protocol (instead of via FTP or another method).

[* http://www.ietf.org/rfc/rfc2518.txt ] 

WebDAV itself has become a sprawling set of features.  One of the most
popular is the "Versioning Extensions" to WebDAV (beginning with
RFC3253*) aka "DeltaV".  Newer Apache distributions support DeltaV.

[* http://www.ietf.org/rfc/rfc3253.txt ]

Probably the first mainstream use of DeltaV is by Subversions, a
replacement configuration management (CM) system for CVS.  Subversions
is both a command line interface (CLI) drop-in replacement for CVS,
but also offers a WebDAV front-end c/o Apache.

CVS itself has _always_ been usable for things _other_ than software
development.  Many sysadmins use it for server/workstation configuration
management.  And there were even plug-ins written for office suites
to handle uploading documents.  Unfortunately, you typically had to
patch CVS with Xdelta or something else to get better binary file
revisioning.  And there was also a text/binary hacking issue (at least
that I always ran into) so I limited my use to text-only files.

I haven't checked out Subversions yet myself.  But it has an integrated
Xdelta or some other binary file revisioning capability.  I know it
handles binary files much better now, at least it is "more friendly"
than CVS was.  It's merge code is still rather simplistic (CVS-based),
so it cannot merge binary files (yet?).

In a nutshell, there has to be a "DeltaV backend" if you are going to
take advantage of the capability in Apache.  Subversions is one of the
first, generic backends available.  I'm sure you could find another that
might be more specific to your application.  Or you could even write your
own for specific tasks.


-- 
     Linux Enthusiasts call me anti-Linux.
   Windows Enthusisats call me anti-Microsoft.
 They both must be correct because I have over a
decade of experience with both in mission critical
environments, resulting in a bigotry dedicated to
 mitigating risk and focusing on technologies ...
           not products or vendors
--------------------------------------------------
Bryan J. Smith, E.I.            b.j.smith@ieee.org



-
To unsubscribe, send email to majordomo@silug.org with
"unsubscribe silug-discuss" in the body.