same authorization.

   In order to prevent these collisions a lock token MUST be submitted
   by an authorized principal in the If header for all locked resources
   that a method may interact with or the method MUST fail.  For
   example, if a resource is to be moved and both the source and
   destination are locked then two lock tokens must be submitted, one
   for the source and the other for the destination.

7.6.1 Example - Write Lock

   >>Request

   COPY /~fielding/index.html HTTP/1.1
   Host: www.ics.uci.edu
   Destination: http://www.ics.uci.edu/users/f/fielding/index.html
   If: <http://www.ics.uci.edu/users/f/fielding/index.html>
       (<opaquelocktoken:f81d4fae-7dec-11d0-a765-00a0c91e6bf6>)

   >>Response

   HTTP/1.1 204 No Content

   In this example, even though both the source and destination are
   locked, only one lock token must be submitted, for the lock on the
   destination.  This is because the source resource is not modified by
   a COPY, and hence unaffected by the write lock. In this example, user
   agent authentication has previously occurred via a mechanism outside
   the scope of the HTTP protocol, in the underlying transport layer.




 
RFC 2518                         WEBDAV                    February 1999


7.7 Write Locks and COPY/MOVE

   A COPY method invocation MUST NOT duplicate any write locks active on
   the source.  However, as previously noted, if the COPY copies the
   resource into a collection that is locked with "Depth: infinity",
   then the resource will be added to the lock.

   A successful MOVE request on a write locked resource MUST NOT move
   the write lock with the resource. However, the resource is subject to
   being added to an existing lock at the destination, as specified in
   section 7.5. For example, if the MOVE makes the resource a child of a
   collection that is locked with "Depth: infinity", then the resource
   will be added to that collection's lock. Additionally, if a resource
   locked with "Depth: infinity" is moved to a destination that is
   within the scope of the same lock (e.g., within the namespace tree
   covered by the lock), the moved resource will again be a added to the
   lock. In both these examples, as specified in section 7.6, an If
   header must be submitted containing a lock token for both the source
   and destination.

7.8 Refreshing Write Locks

   A client MUST NOT submit the same write lock request twice.  Note
   that a client is always aware it is resubmitting the same lock
   request because it must include the lock token in the If header in
   order to make the request for a resource that is already locked.

   However, a client may submit a LOCK method with an If header but
   without a body.  This form of LOCK MUST only be used to "refresh" a
   lock.  Meaning, at minimum, that any timers associated with the lock
   MUST be re-set.

   A server may return a Timeout header with a lock refresh that is
   different than the Timeout header returned when the lock was
   originally requested.  Additionally clients may submit Timeout
   headers of arbitrary value with their lock refresh requests.
   Servers, as always, may ignore Timeout headers submitted by the
   client.

   If an error is received in response to a refresh LOCK request the
   client SHOULD assume that the lock was not refreshed.

8  HTTP Methods for Distributed Authoring

   The following new HTTP methods use XML as a request and response
   format.  All DAV compliant clients and resources MUST use XML parsers
   that are compliant with [REC-XML].  All XML used in either requests
   or responses MUST be, at minimum, well formed.  If a server receives




 
RFC 2518                         WEBDAV                    February 1999


   ill-formed XML in a request it MUST reject the entire request with a
   400 (Bad Request).  If a client receives ill-formed XML in a response
   then it MUST NOT assume anything about the outcome of the executed
   method and SHOULD treat the server as malfunctioning.

8.1 PROPFIND