Checking Out WebDAV

I've been working with the new release of Visual Studio and I'm particularly impressed with the power of the development environment. I used to be jealous of C++ and Visual Basic developers because their toolboxes made their life so much easier than a Web developers. But today, with tools like Microsoft's FrontPage, Macromedia's Dreamweaver, and Net Object's Fusion, no Internet developer should ever envy the traditional application developers' working environment.

Except for one thing.

Web authoring becomes sticky when two or more people work on the same content. Long ago, applications developers solved this problem by instituting a check out system that allowed multiple programmers to work on the same application. If one programmer needs to revise a module he or she simply checks it out, making it unavailable for others. This prevents someone from accidentally making a series of changes that would be overwritten when the original programmer returned the program to the master library. What's missing is a similar tool for web development and collaboration. Luckily, this is a hole that will soon be plugged.

To support distributed authoring across the Internet, there needs to be a standards-based approach to collaborating on HTML documents and applications. Just such an approach is emerging, and it is called WebDAV: World Wide Web Distributed Authoring and Versioning.

WebDAV is nothing more than a set of extensions to the underlying communications mechanism of the web, Hypertext Transport Protocol (HTTP). A working group inside the Internet Engineering Task Force spent almost two years developing a set of stable specifications that allows multiple vendors' distributed authoring environments to work together. Their initial work extends HTTP to include functions beyond the traditional request/response paradigm of the web.

One set of extensions allows HTTP to provide an "overwrite protection" service, neatly avoiding the problem of losing updates when two people modify the same document at the same time. WebDAV does this by locking the page and its contents. While the lock is in place only the person who checked out the web page can update the server with a new version.

Another important set of WebDAV extensions allows HTTP to return properties of the pages as well as the pages themselves. Web applications have many pieces of information associated with them, such as author, page creation date, title, subject, and length. On the Web this information often is called "metadata." Web metadata is becoming a crucial part of making it easier to find things on the Web. WebDAV assists web collaborators by allowing HTTP to return properties of pages without retrieving the entire web page and its associated graphics, multimedia and scripts.

Another key WebDAV feature is called namespace management. Traditional source code management systems -- like Microsoft's SourceSafe -- rely on the underlying file system to move files between the server and the programmer's authoring environment. On the Internet this approach doesn't work. While you may be using FrontPage to author your web documents, the person you are working with may be using a different product under Unix. WebDAV's namespace management effectively replaces the file system with a series of HTTP commands that allow authors to list, copy, and rename web resources on a WebDAV server. Even for users who are not actively authoring documents, navigating a WebDAV compliant server is just like using their local file system.

On first blush WebDAV serves an obvious need, and once implemented in products web developers will never have to envy traditional applications development environments again. But the question is will WebDAV ever be implemented?

One good sign is that WebDAV has the active support of key vendors in document authoring. Microsoft, Netscape, Xerox, IBM and Novell all are active in the development of WebDAV. At IETF working group sessions, these vendors have all been intensely focused on getting the standards in place so products can be delivered.

For its part, Microsoft has taken implementation of WebDAV a step further. WebDAV support is built into the current beta releases of Office 2000 and Windows 2000. When the beta release of FrontPage 2000 hits the web this winter, expect to see substantial support for WebDAV built-in there, too.

Other vendors also are seeing that WebDAV can be extended past its roots as a Web collaboration system. If you have spreadsheets, reports, and presentations that you work on with other people in the office, why not use a vendor-neutral, industry standard approach to collaborative authoring? In the past, there wasn't one. But, with the next generation of workstation tools a true collaborative environment will exist for everyone, not just applications developers. I can't wait to -- ahem -- check it out. -- Mark McFadden is a consultant and the communications director for the Commercial Internet eXchange (Washington). Contact him at