18. DAV Compliance Classes

A DAV-compliant resource can advertise several classes of compliance. A client can discover the compliance classes of a resource by executing OPTIONS on the resource and examining the "DAV" header which is returned. Note particularly that resources, rather than servers, are spoken of as being compliant. That is because theoretically some resources on a server could support different feature sets. For example, a server could have a sub-repository where an advanced feature like versioning was supported, even if that feature was not supported on all sub-repositories.

Since this document describes extensions to the HTTP/1.1 protocol, minimally all DAV-compliant resources, clients, and proxies MUST be compliant with [RFC2616].

A resource that is class 2 or class 3 compliant must also be class 1 compliant.

18.1. Class 1

A class 1 compliant resource MUST meet all "MUST" requirements in all sections of this document.

Class 1 compliant resources MUST return, at minimum, the value "1" in the DAV header on all responses to the OPTIONS method.

18.2. Class 2

A class 2 compliant resource MUST meet all class 1 requirements and support the LOCK method, the DAV:supportedlock property, the DAV:lockdiscovery property, the Time-Out response header and the Lock-Token request header. A class 2 compliant resource SHOULD also support the Timeout request header and the 'owner' XML element.

Class 2 compliant resources MUST return, at minimum, the values "1" and "2" in the DAV header on all responses to the OPTIONS method.

18.3. Class 3

A resource can explicitly advertise its support for the revisions to [RFC2518] made in this document. Class 1 MUST be supported as well. Class 2 MAY be supported. Advertising class 3 support in addition to class 1 and 2 means that the server supports all the requirements in this specification. Advertising class 3 and class 1 support, but not class 2, means that the server supports all the requirements in this specification except possibly those that involve locking support.

Example:

DAV: 1, 3