TABLE OF CONTENTS
CAMERON LAIRD and KATHRYN SORAIZ
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 server.
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 until now.
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 (see Figure 1).
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 with email."
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' applications.
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 (see Figure 2), or right-click on them to inspect properties. These examples hint at how Zope's support of WebDAV will multiply a site's productivity.
|Figure 2. Zope's support of WebDAV allows Internet Explorer 5 users to drag-and-drop Zope constructs.|
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 to accept.
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.