This article originally appeared at: http://webserver.cpg.com/wa/4.4/
CAMERON LAIRD and
Zope Builds on its Success
A second look at Digital Creations' open-source
application server now that it supports WebDAV.
Construction of better Web site development tools is a "guaranteed
opportunity" for start-ups. That's what Bill Gates said in a
widely reported presentation he made in early March in Yokohama,
Japan. It certainly seems to be working out for Digital Creations, a
Fredericksburg, VA-based company that provides consulting
services for Web business applications, and its Zope application
In our December column, "Principia: A
Different Breed of Application Server," we profiled the
Zope application server and the company behind it. (Digital
Creations decided to sidestep any chance of trademark litigation
by changing the product's name from Principia to Zope.) Because
that particular installment of WebAdmin sparked interest
among our readers, we think it's time to update Digital Creations'
fortunes and consider the company's latest technological advances;
namely, its support of Web-based Distributed Authoring and
Versioning, or WebDAV.
Remember that Digital Creations is an unusual company. While
the open-source concept of giving away key intellectual assets
has become respectable enough during the past year to appear in
mainstream publications, Digital Creations pushes the practice to
its limit. The company's most recent open-source product release
provides full support for the emerging WebDAV protocol. Let's
look first at this new standard, and consider why Digital
Creations thinks it can profit by charging nothing for what IBM
Corp., Microsoft Corp., Novell Inc. and other major players agree
is a strategic competitive advantage.
Suppose you have a document that you want to show the world.
How do you accomplish this? You make it available through HTTP.
HTTP solutions are readily available, there's plenty of
information around about how to deploy them and replacing one
vendor's solution with another is fairly straightforward. But
what if you want to edit that document, or worse, you want
someone else to edit it? Now you're in trouble. As Web site
administrators, we often have to train our content managers in
abstractions such as FTP, shared file systems, platform-specific
file privileges, security, versioning and many other
complications before they can actively perform useful maintenance
of Web-based documents. There is no standard process across the
industry for content workers to perform editing. At least not
WebDAV to the Rescue
The WebDAV protocol promises to cut through this excessive
complexity. It is an extension to HTTP that facilitates efficient,
secure maintenance of remote Web servers.
WebDAV has considerable "official" standing,
including its own defining RFC document (RFC 2518),
an active Internet Engineering Task Force (IETF) Working Group,
a reference extension to the free Apache Web server called mod_dav and
announcements from Microsoft that Internet Information Server (IIS)
Version 5 and Office 2000 will fully support WebDAV. Greg Stein,
independent developer and former Microsoft development manager,
is coordinating and authoring much of the WebDAV activity.
What does all this mean to you? Probably quite a lot during
the coming year. Until now, each Web site content manager or
application server--such as Microsoft FrontPage, America Online
Inc.'s AOLserver and HAHT Software Inc.'s HAHTsite--has had its
own proprietary method for managing a remote site. Each product
requires specific training, and because none of them seem exactly
commensurable, project teams moving between different
technologies must often wrestle with product inconsistencies.
If WebDAV doesn't solve all these problems, it certainly
clarifies them and makes them manageable. Several practical
interoperating WebDAV clients and servers are already available.
For a quick demonstration of the technology, take a look at sitecopy, a prototype
open-source WebDAV client that replicates Web sites between hosts.
In the more consumer-oriented market, Microsoft Internet Explorer
Version 5 is an example of an application that supports WebDAV.
If, for example, you perform the function, "Open as a Web
Folder," in Internet Explorer 5, you can initiate a WebDAV
transaction (figure can be seen in the original article).
WebDAV will win. We expect that all the proprietary approaches
to Web site management will adjust to the capabilities of this
unifying protocol in the next few years. More to the point, those
of us who are responsible for managing Web sites will win,
because WebDAV will dramatically streamline the current confusion
of approaches. As Jim Whitehead, research assistant at the
University of California at Irvine, puts it, "WebDAV
transforms the read-only Web into a writeable, collaborative
medium.... In business, the ability to easily collaborate on
documents and spreadsheets within a company, and between
companies, is a big improvement over today's clunky file passing
WebDAV in the Zope Toolkit
Of all the application server vendors out there, Digital
Creations seems to appreciate this efficiency best. It's a
natural fit. The Zope application server has always emphasized a
highly structured "Web object" model, which gives it
unique maintainability and scalability. In addition to Zope
providing an interface to proprietary Web publishing solutions,
Digital Creations' mid-March announcement of full support for
WebDAV deepens its commitment to industry standards. Managing
Zope's Web objects through the WebDAV protocol merely simplifies
interoperability with other tools on the market.
As mentioned in our earlier column, Zope is highly modular and
flexible. Everything about it can be scripted using the open-source
Python programming language, and all of its pieces can be easily
swapped in or out. Many sites that use proprietary content
managers, or application servers, now complement them with Zope.
Zope's parts can fill in the functionality gaps of other products
because Digital Creations builds on standard, open interfaces,
allowing its parts to cooperate well with competing vendors'
In December, Digital Creations was particularly proud of its
out-of-the-box capabilities, but recently the company has begun
to emphasize Zope's WebDAV support. Now, all of Zope's existing
features are accessible in a fully standardized way through the
WebDAV protocol. Zope can manage arbitrarily complex objects
through the Web, including guestbooks, collaborative applications
and discussion archives. Zope extends file system organizational
principles to safeguard all of these instances in its object
database. In addition, WebDAV clients can undo operations on
objects, search for earlier versions of them and manage security
settings. If you are interested in learning more, Digital
Creations offers a taste of WebDAV capabilities with its open Zope/WebDAV Test Server. (A
growing amount of traffic for this site originates from Microsoft's
Web site, so it's only natural to guess that Microsoft is using
the Zope/WebDAV Test Server to validate at least some of Internet
Explorer 5's WebDAV capabilities.)
Internet Explorer 5 demonstrates several of the ways in which
WebDAV is more than just another protocol. Zope's strong "Web
objects" model is the foundation that allows Internet
Explorer 5 users to drag-and-drop Zope constructs (figure can be
seen in the original article), or right-click on them to inspect
properties. These examples hint at how Zope's support of WebDAV
will multiply a site's productivity.
Digital Creations for the Long Haul?
Zope's technology is frankly intoxicating. It's exciting to be
able to "glue" together so many disparate technologies
to create a dynamic, yet maintainable, Web site. Is it prudent to
do so, though? How much can Zope be worth if Digital Creations
gives it away?
Quite a lot, in our experience. Digital Creations President
Paul Everitt tells us that the company's "consulting clients
are paying for the open-source development," and the number
of clients has increased since the release of the source code.
Similarly, the Zope user community has mushroomed. Giving away
Zope has apparently helped the company gain market share it could
never have captured with a more traditional business model.
Ted Patrick, chief information officer of Nashville, TN-based
Web site developer Indigo
Networks LLC, is a Zope enthusiast. "We simply get more
done with Zope," Patrick says. Although Indigo has tried
many different application servers, Patrick says the supple Zope
model for Web object management is the best foundation for rapid
and reliable development.
Zope's future looks more certain than that of more expensively
marketed, commercial competitors such as Sun Microsystems Inc.'s
NetDynamics and Allaire Corp.'s ColdFusion. The development path
for NetDynamics, for example, seems determined more by the grand
strategy of corporate alliances than technological opportunities
or customer needs.
The entire Digital Creations story isn't rosy, of course. A
few developers told us privately that they avoid using Zope for
simple sites with high-performance requirements, and despite its
recent rapid growth, Zope's user base remains much smaller than
the other application servers on the market. In addition, its
business model is perhaps too unorthodox for some organizations
Most important, the Zope story is still a difficult one to
tell. Developer enthusiasm for Zope involves a balance of many
elements--its flexibility, strong support for a variety of
external databases, scriptability, slick support for
collaborative development and compatibility with industry
standards--that is too subtle to be explained in less than 25
words. Zope has always been different--more open, less
graphically slick--than the other products calling themselves
application servers. The benefits of platform neutrality and deep
scriptability are lost on companies that organize work around
particular point-and-click habits of reaching results. Finally,
the WebDAV standard itself remains incomplete in important
dimensions such as versioning and security.
Despite these reservations, recent events have reinforced our
original conclusion: Zope has plenty to offer, and is worth a
look. It's particularly timely to learn how to use Zope as a
WebDAV server, both to keep up with this intriguing new protocol
and also to help solve the most practical content management
problems of day-to-day Web site administration.
CAMERON LAIRD and KATHRYN SORAIZ
manage their own software consultancy,
Network Engineered Solutions,
from just outside Houston, TX.
Copyright (c) 1999 Computer
Publishing Group, Inc.