![]() ![]() ![]() Section 9 describes the new HTTP headers used with WebDAV methods. Otherwise, parameters are encoded within HTTP headers. As a rule of thumb, parameters are encoded in XML entity bodies when they have unbounded length, or when they may be shown to a human user and hence require encoding in an ISO 10646 character set. The use of XML to encode method parameters was motivated by the ability to add extra XML elements to existing structures, providing extensibility and by XML's ability to encode information in ISO 10646 character sets, providing internationalization support. "Unlike HTTP/1.1, WebDAV encodes method parameter information either in an Extensible Markup Language (XML) request entity body, or in an HTTP header. The name and value of a property is expressed as a well-formed XML element, where the name of the property is the name of the XML element, and the value of the property MUST be either blank, or a well-formed XML element value." The name of a property identifies the property's syntax and semantics, and provides an address with which to refer to a property. "The DAV property model is based on name/value doubles. Version management can also support collaboration by allowing two or more authors to work on the same document in parallel tracks." The ability to store important revisions of a document for later retrieval. This prevents the "lost update problem" in which modifications are lost as first one author, then another writes their changes without merging the other author's changes. The ability to keep more than one person from working on a document at the same time. ![]() The ability to copy and move Web pages, and to receive a listing of pages at a particular hierarchy level (like a directory listing in a file system). Also, the ability to link pages of any media type to related pages. The ability to create, remove, and query information about Web pages, such as its author, creation date, etc. The WebDAV working group "found that there was a pressing need to develop standard extensions to the HyperText Transfer Protocol (HTTP) for the following capabilities: 1) Metadata. It is a set of extensions to the HTTP protocol which allows users to collaboratively edit and manage files on remote web servers." What is WebDAV? "Briefly: WebDAV stands for 'Web-based Distributed Authoring and Versioning'. The Distributed Authoring and Versioning (WebDAV) standard was approved by the IETF in December, 1998. It uses XML." The Working Group chairman is Jim Whitehead (University of California, Irvine). "WebDAV is an Internet Engineering Task Force (IETF) working group that seeks to extend HTTP 1.1 for distributed authoring and versioning. ![]()
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