HTTP and WebDAV Standards

Exchange supports the standard HTTP operations outlined in RFC 2616 and the WebDAV operations outlined in RFC 2518. WebDAV features that are specific to Exchange are listed below.

Locking

Locking prevents two or more users from overwriting each other's modifications when they save to a given Uniform Resource Indicator (URI). Locking also lets you know if someone else is currently modifying a resource.

Exchange implements Locking in the following ways:

• Time-outs must be set for a finite amount of time.
• Exchange supports exclusive and shared locks.
• The only way to know if a user has locked a file in Exchange is to use the HTTP verb PROPFIND.

Properties

A property is data that describes the state of a resource. A property can include bibliographic information, such as author, title, publisher, subject, constraints on usage, and PICS ratings. Properties have many uses, such as supporting searches on property values, enforcing copyrights, and creating catalog entries.

When a user who is locally connected to a server asks for a property, the server returns a property that does not include a virtual server name; the property just provides a path to the resource.

As the WebDAV RFC specifies, a client can send an ALLPROP request in the body of a PROPFIND command to receive all properties on an item. Because Exchange stores so many properties, only the default properties for an object are returned. To get the entire list of properties stored by Exchange, the PROPFIND request must use a special field in the following way. To send the PROPFIND request to the server, use a Microsoft Visual Basic script and the XMLHTTPRequest object provided with Microsoft XML. Using a Visual Basic script, you must include the following PROPFIND request:

<D:propfind xmlns:D = DAV:, xmlns:E= 
http://schemas.microsoft.com/exchange/>


 <D:allprop> <E:allprop/> </D:allprop>


</D:propfind>

Namespace

Namespace allows users to direct the server to copy and move Web resources. Tasks can include copying, moving, and renaming a resource.

WebDAV allows you to use the # or %23 characters in URLs, but you cannot use the pound sign in Exchange Information Store. The character # in the subject of an e-mail message will be replaced by %2523. You can use %2523 if you want to create a new resource that contains the character # in its name.

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