More XMLMap: XML about Content (1/3) - exploring XML
More XMLMap: XML about Content
Continuing our charting of the XMLMap we examine the use of XML as a content description and content transfer format. Discussions about tagging documents with meta data and publishing documents to Web servers conincided with the development of XML, and created first ideas on how to use XML in or with non-XML data.
Content Management: HTTP++
While creating Web pages was relatively simple from the beginning, it became even easier with the advent of special-purpose HTML editors ranging from developer tools to end user applications. Moving your freshly-created content to the Web server for all to see was a different challenge altogether: Providers still use FTP for this task, which is hard to configure and debug for end users, and is also a firewall-unfriendly protocol that might be blocked in most corporate firewalls. It is also difficult to implement FTP seamlessly into an HTML editor and deal with all possible failure scenarios.
So most vendors of HTML editors and servers went on to stretch and extend HTTP in various ways to turn the Web from a one-way street into a two-way street, where the client can send content to a server by means other than posting a few form fields. Even with built-in HTTP mechanisms like the capability to post a multi-part MIME message including arbitrary files, developers were quickly confronted with a new class of problems:
- Where is the newly uploaded content supposed to go on the server?
- How to deal with multiple versions of the same file and concurrent uploads?
With these challenges in clear view, vendors of Web servers and editors convened to develop a document exchange protocol based on XML, designed to run over HTTP, that would create interoperability between editors and servers in the same way that standard HTTP provides interoperability between Web browsers and servers.
Briefly, WebDAV stands for "Web-based Distributed Authoring and Versioning". It is a set of extensions to the HTTP protocol which allows users to collaboratively edit and manage files on remote Web servers. WebDAV is now integrated in most HTML editors and even Office products.
The DeltaV protocol is an extension to the WebDAV protocol. Despite its name, WebDAV only provides facilities for remote collaborative authoring of documents, without any versioning capabilities. Initially, the WebDAV working group had wanted to define a protocol for remote versioning, but took much longer than expected just to finish the base remote authoring protocol. As a result, the WebDAV working group postponed work on versioning features. The DeltaV working group picked up where WebDAV left off, taking on the goal of adding versioning to the Web, as well as the more ambitious goal of remote configuration management.
How to find documents again.
Produced by Michael Claßen
Created: Feb 03, 2003
Revised: Feb 03, 2003