Subject: what is lock-null resource

From: "Tao Wan" <[email-masked]>
Date: Thu, 14 Jun 2001 08:36:12 -0700

Hi,
       I read the RFC2518 and not sure what is lock-null resource for.
could
   you please give me a example to explain its purpose or function. Thanks

   tao

---

From: "Jim Whitehead" <[email-masked]>
Date: Thu, 14 Jun 2001 08:55:55 -0700

Accidentally caught by the spam filter.  I've added [email-masked]
to the accept2 list, so future email from this address will go through to
the list.

- Jim

-----Original Message-----
From: Dr. Michael Evans [mailto:[email-masked]]
Sent: Thursday, June 14, 2001 8:54 AM
To: [email-masked]
Subject: [Moderator Action] RE: what is lock-null resource

>> could you please give me a example to explain its purpose or
>>function.
Tao,

A null resource is defined as “…a resource which responds with a 404 (Not
Found) to any HTTP/1.1 or DAV method except for PUT, MKCOL, OPTIONS and
 LOCK”.  In other words, a null resource is one that does not physically
exist on the server, but whose URL does.  Locking a null resource has the
effect of reserving the URL.  In this way, a write-locked null resource (or
lock-null resource) ensures that no other user can use the specified URL
until it is unlocked.

Cheers,

Mike

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]]On Behalf Of Tao Wan
Sent: 14 June 2001 16:36
To: [email-masked]
Subject: what is lock-null resource

Hi,

   tao

---

From: [email-masked]
Date: Fri, 15 Jun 2001 11:04:33 +0100

"Dr. Michael Evans" <[email-masked]> wrote:
> A null resource is defined as a resource which responds
> with a 404 (Not Found) to any HTTP/1.1 or DAV method except
> for PUT, MKCOL, OPTIONS and LOCK

ö

and UNLOCK.

> In other words, a null resource is one that does not physically
> exist on the server, but whose URL does.

I can't let that sentence go <g>.

The protocol does not state which resources physically exist and which do
not, that is the perogative of the server implementation.  Given that the
lock null resource has all the mandatory DAV properties I would imagine
that many server implementations _would_ have to 'physically' persist a
lock null resource.

As for the URL physically existing, "As far as HTTP is concerned, Uniform
Resource Identifiers are simply formatted strings which identify--via name,
location, or any other characteristic--a resource." [RFC2616]

> Locking a null resource has the effect of reserving the URL.
> In this way, a write-locked null resource (or lock-null
> resource) ensures that no other user can use the specified
> URL until it is unlocked.

Tim