Subject: Re: Issue: SOURCE_PROPERTY_UNDERSPECIFIED

From: "Jason Crawford" <[email-masked]>
Date: Thu, 27 Jun 2002 15:13:02 -0400

> > 3) A dynamic page is being served at a given URL. The author wants to
> > update the implementation of that dynamic resource. Where does he PUT
the
> > updated implementation? (I think we've answered the basic form of this
> > question via the dav:source propety. Questions like whether the update
> > will be refelcted immediately can be answered later.)
> The dynamic content resource will point to other resources that the
client
> might be interested in authoring to change the content of both resources.

Agreed :-)

> If the server is capable of handling PUT on a "dynamic content" resource,
> then it may also support direct editing of the resource.  Day Software's
> products support that kind of editing, but as far as the client is
> concerned
> it is just performing methods on a WebDAV resource.  There is no
difference
> between the two EXCEPT that there are some circumstances when the client
> needs to be encouraged to go elsewhere (such as when the author wishes to
> edit a presentation template).  The principles are the same.  A source
> property is merely a mechanism to supply metadata for a relationship
> between two or more resources.

It's not central to the point of your posting as a whole, but I'll comment
on
this part.   I think you're suggesting that the source property could point
at
the resource itself.  I agree in prinical this can be done, but it does
create
another issue that we would then want to clarify.

Is the source property telling you where you can GET the source... or where
you
can PUT it.  Obviously if you do a GET on the dynamic resource itself, you
will
not get the source of the implementation.  Given your comment, we should
probably
be clear about that.

> > 4) An author wants to no longer serve dynamic content at a specific
URL.
> > What URL does the author DELETE?

> The URL they want to DELETE, which, depending on the implementation, may
> result in a suggestion to the author that they need to DELETE some other
> resource instead (or as well).

Okay.  And what is the mechanism for the server to do the "suggesting"?  (I
assume it's a mechanism that distinguishs between redirects that require
user confirmation and those that don't.)

> > 6) Make sure the answers to the questions above don't cause problems
for
> > servers that require explicit client controlled mapping operations.
> A server that requires explicit name bindings will naturally require
> operations on those bindings that make them explicit.
Obviously if it didn't require it this might be yet another advantage to a
design.   Anyway... I understand that you're saying it's not important
in your opinion.

> The purpose of the source property is to allow a WebDAV-able resource to
> supply information to an authoring client regarding the nature of its
> underlying implementation by providing links to other resources that
> make up that implementation.  That's all.  It doesn't need to do anything
> more to justify its existence.
I'll take it to mean that just supporting 2 & 3 (& possibly 4) is fine with
you.

------------------------------------------
Phone: 914-784-7569,   [email-masked]

---

From: "Julian Reschke" <[email-masked]>
Date: Thu, 27 Jun 2002 21:35:24 +0200

>From: [email-masked] [mailto:[email-masked]]On
Behalf Of Jason Crawford
>Sent: Thursday, June 27, 2002 9:13 PM
>To: Roy T. Fielding
>Cc: 'Webdav WG (E-mail)'
>Subject: Re: Issue: SOURCE_PROPERTY_UNDERSPECIFIED
>
> ...
difference
on
at
create

I don't think he did.

you
will
probably
>be clear about that.

The source property lists sources. It doesn't tell you anything about
whether the dynamic resource supports PUT, and what effect that would have.
Note also that source resources may be dynamic resources as well.

URL.
>user confirmation and those that don't.)

Good point. Roy, did you have any specific (existing) mechanism in mind?

---

From: "Roy T. Fielding" <[email-masked]>
Date: Thu, 27 Jun 2002 14:22:59 -0700

>> It's not central to the point of your posting as a whole, but I'll 
>> comment on
>> this part. I think you're suggesting that the source property could 
>> point at

No, I was not suggesting that a resource would point to itself as a
source -- it already gives that information to the client via the methods
allowed on itself.  What I was suggesting is that there is no such thing
as a resource type.  Resources simply allow or do not allow methods,
and link to or do not link to other sources.   It is a web.  The job of
the client is to let the author know that this web exists when it
encounters a resource with links to sources.

> Good point. Roy, did you have any specific (existing) mechanism in mind?

A redirection.  There is no such thing as a redirected DELETE that doesn't
require user confirmation.  However, if the client accesses a resource
using WebDAV and that resource does not allow DELETE and that resource
does have a source link, then isn't it reasonable for the client to ask
the user if they would really like to delete the source resource instead?
Client implementations can figure that one out for themselves.

....Roy

---

From: "Julian Reschke" <[email-masked]>
Date: Fri, 28 Jun 2002 16:33:54 +0200

> From: [email-masked]
> [mailto:[email-masked]]On Behalf Of Roy T. Fielding
> Sent: Thursday, June 27, 2002 11:23 PM
> To: Julian Reschke
> Cc: Jason Crawford; 'Webdav WG (E-mail)'
> ..

Granted, but this would only work well if there's only one source resource,
right?

---

From: "Roy T. Fielding" <[email-masked]>
Date: Fri, 28 Jun 2002 11:17:56 -0700

> Granted, but this would only work well if there's only one source 

300 Multiple Choices.

....Roy