1.7 Roles for WebDAV

Although WebDAV is a useful protocol for distributed authoring of Web pages, and clearly WebDAV has a larger role to play, there are different ideas of what that larger role is.

CM Interoperability

CM systems include a wide variety of enterprise and group-oriented software. The lines are blurry here, because some products are sold as "document management," others "knowledge management," others "file management" or even "team portal," and each name implies a different level of functionality and complexity. Some examples include Microsoft Sharepoint Server, Adobe InDesign and GoLive, and Lotus Notes.

CM systems have more features than file systems do. They've been around for many years but for most of that time have been unable to interoperate with each other or with most other software. Until recently, CM users usually had to install a special client software program and use it separately from their productivity applications. Most of these systems now support Web interfaces, so client software doesn't have to be installed locally. Some even extend productivity applications such as Office with custom add-ins. However, no matter what, using the CM interface requires actions different from normal local authoring.

WebDAV could become a common-denominator protocol, allowing authoring applications to save to CM systems even when the authoring application is from a different vendor. WebDAV could also be useful for administrators to migrate documents into or out of CM systems or to link multiple systems.

Common-Denominator Information Retrieval

Microsoft's take on WebDAV clearly encompasses the CM interoperability view but takes it further, to data not traditionally viewed as simple standalone electronic documents. Microsoft's presentations make it clear that Microsoft views HTTP and HTTP-based protocols as the key to client/server interoperability. It's the common way for clients to interoperate with information on a server, even if that information is also available via other specialized methods or protocols. The content stored this way is by no means limited to Web pages and Office documents. Already, it includes email messages, newsgroup postings, address book information, shared and personal calendars, appointments, and tasks. Figure 1-2 shows a few of the clients and servers that may already use WebDAV to interoperate.

Figure 1-2. Common client/server language for managing documents.

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One drawback to this approach is that WebDAV doesn't offer the complete set of functionality each application requires. For example, the calendar server products Microsoft and Lotus offer both send appointment reminders from the server to the client, but HTTP and WebDAV do not handle server-initiated messages.

Networked File System Access

Many people now view WebDAV as a nascent protocol for a networked file system, one that is suitable for use on or with the Web [Stein02]. Microsoft's Web Folders feature exemplifies this approach, treating the WebDAV repository just like a networked file share. Oracle's Internet File System (IFS) provides a common repository for hosting many kinds of files and supporting several Internet protocols, including WebDAV. Universities are providing students with personal file space on WebDAV servers rather than on traditional network file servers.

In many ways, WebDAV is more suitable for truly remote file systems than the protocols that were originally designed for intranets. The Internet tends to be a high-latency environment compared to intranets; each request takes longer to arrive at its destination, even if the bandwidth is equal. Protocols designed for low-latency intranet environments tend to use many interchanges to accomplish a task. For example, Microsoft's protocol for accessing file shares (SMB) performs a number of round-trip operations to change a file. This can take several seconds if the client has to wait for several server responses. The same operation is done with a single PUT request in HTTP.

On the other hand, WebDAV is missing one or two features commonly implemented by networked file systems, such as server-to-server copy. Most important, WebDAV client implementations aren't yet as mature or as fully integrated into the operating system as the networked file system client implementations.

Source Control Systems

WebDAV can be the standard access protocol for versioning systems, including source code repositories [Stein99], [Whitehead01]. Many Web sites today are developed with the assistance of a source control system, so DeltaV was designed to handle this task. DeltaV can also be used to access any kind of source code, such as the files that are compiled to build a software product.



WebDAV. Next Generation Collaborative Web Authoring
WebDAV. Next Generation Collaborative Web Authoring
ISBN: 130652083
EAN: N/A
Year: 2003
Pages: 146

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