HTTP 1.1 Methods and Extensions

[This is preliminary documentation and subject to change.]

Note   At this writing, this section documents only a few of the methods available in the WebDAV RFC Specification.

Outlook Web Access conforms to HTTP 1.1 and RFC #2518 (WebDAV).

WebDAV (Web based Distributed Authoring and Versioning) can support various storage models including file system, semi-structured (Exchange store) and relational (SQL server). It does this by providing a simple abstraction using the concepts of “collections”, “resources”, and “properties”.

WebDAV provides resource and property manipulation. XML provides a format for structured data

WebDAV uses XML as part of the protocol. The WebDAV model of properties is based on XML.

• Naming of properties
• Structure of properties
• Transmission of properties

WebDAV was originally intended to add the most useful or necessary functionality to allow HTTP resources to be authored in a collaborative environment.

In a distributed authoring environment, authors need to be able to protect documents from changes, create “collections” which are a kind of resource that can contain other resources, move or copy files from one collection to another, and retrieve/modify metadata (information or properties about resources).

Properties

Every resource (including collections) have Properties

Properties have:

Names (via XML Element)
<R:author/>

Values (via XML tree)
<R:author>Van Van</R:author>

Live vs. Dead Properties

A 'live' property is one that resides on the server and is always current and accurate. A 'dead' property resides on the client and may not be current and accurate. The property may need to be refreshed.

The WebDAV model provides for a client-side store that can be constantly synchronized with the various server-side stores through replication of the most important information. This can provide both efficient online access, as well as support for offline scenarios.

Property Structure

A property can have complex a structure

<V:VCard>

<V:Name>Van Van</V:Name>

<V:Tel>555-1212</V:Tel>

<V:Email>vanvan@microsoft.com </V:Email>

</V:VCard>

WebDAV was designed to:

• Facilitate the sharing of content across the team
• Support Collaboration
• Support Distributed/Different clients

Resource/Collection manipulation

WebDAV provides the following tools for the manipulation of resources and collections.

• PUT/MKCOL : creates a resource/collection
• DELETE : deletes a resource/collection
• COPY/MOVE : copies/moves a resource/collection
• LOCK/UNLOCK : locks/unlocks a resource/collection

Property manipulation

WebDAV provides the following tools for the manipulation of properties.

• PROPFIND : retrieves properties
• PROPPATCH: sets or deletes properties

Features

• Namespace management – folder/document copy, move, list
• Resource metadata – describe, query info about documents
• Overwrite protection
• Version management

Supported Operations

• Get – get information
• Put
• Delete
• Options

Depth

RFC 2518 introduces the Depth header to allow the programmer to manipulate entire hierarchies of the namespace based on their child relations.

The Depth header, when used on a collection resource, allows one to specify that a method should apply to the resource and to its children for the number of levels specified by the Depth header.

The Depth header currently supports 0, 1 and infinite levels.

Note - the Depth header is to be ignored if it is not used on a collection resource.