The new WebDAV (Distributed Authoring and Versioning) protocol allows any client Read/Write access to the database over HTTP. WebDAV is an extension of HTTP 1.1. It is used for general data access over the Internet, where the data is stored on the server but is used on the client. It supports various storage models, including file system, semi-structured (Exchange), and relational (SQL Server). WebDAV clients can be constantly synchronized to the server-side databases through replication. This provides efficient online access and offline usage.
WebDAV can be used in the following ways:
Exchange uses WebDAV to provide access to the database to any Internet client. WebDAV defines protocol elements used for file version management and uses XML as the format for transmitting data elements.
WebDAV is automatically installed with Exchange. No additional installation or configuration is required. WebDAV is an Internet engineering task force (IETF) draft standard, and Microsoft has added the following extensions to it that Exchange uses:
|Distributed Authoring Search and Location (DASL)||Extends the search functionality to allow for persistent searches, row ranges, and SQL.|
|Versioning||Adds check-in and check-out and other versioning properties|
|Replication||For offline clients. Changes at the server are synchronized by download|
|Transactions||Client-level logging of transactions to submit operations and either commit or rollback|
|Access control||Windows NT security descriptors set for distributed authoring.|
|Structured documents||For documents with multiple members, such as MIME multipart documents or Web pages with images|
|Notifications||Messages sent to the client by the server, according to the details of the client subscription|