Subject: Re: RFC2445 Property Change Control Request: Disallow Allow Multiple ATTENDEE Properties With The Same Value

From: Doug Royer <[email-masked]>
Date: Mon, 26 Jul 1999 08:54:36 -0700 (PDT)

YES! Good catch.

> From: [email-masked]
> Date: Fri, 23 Jul 1999 15:50:29 GMT
> 
> Folks:
> In section "4.8.4.1 Attendee" of RFC 2445, there is no restriction on
> occurrence of multiple ATTENDEE properties with the same value. This
> practice introduces a problem for recipients and will result in an
> interoperability conflict. For example, you can specify the same ATTENDEE
> value twice, once as a REQ-PARTICIPANT and the other as a OPT-PARTICIPANT
> or even as both a delegatee and delegator! Obviously, this is a whole in
> the specification. I suggest that we close it with a Property Change
> Control request, per section "7.3 Property Change Control" of RFC 2445.
> 
> <pccr>
> 
>    Subject: Property Change Control Request
> 
>    Property Name: ATTENDEE
> 
>    Change Purpose: To correct ambiguity in specification. Change will
>    assure interoperability with the ATTENDEE property and its intended
>    purpose.
> 
>    Define the change: Add the following paragraph to the end of the
>    "Description" clause in section "4.8.4.1 Attendee":
> 
>    "The property MUST NOT be specified more than once with the same
>    property value."
> 
> </pccr>
> 
> -- Frank Dawson
> 
> 
> 
> 

-Doug
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From: Doug Royer <[email-masked]>
Date: Mon, 26 Jul 1999 08:58:30 -0700 (PDT)

> Date: Fri, 23 Jul 1999 11:58:29 -0400
> From: Alexander Taler <[email-masked]>
> 
> This change would preclude the ability to delegate your attendance to
> someone who is already listed as an ATTENDEE.  Is this a reasonable
> restriction?

I don't think so:

	ATTENDEE:...:delegated-to="mailto:User2@somehost":User1@somehost
	ATTENDEE:...:User2@somehost

'User1' can delegate to 'User2'. And 'User2' can be both a paramater
value in the first, and a property value in the second.

-Doug

---

From: Doug Royer <[email-masked]>
Date: Mon, 26 Jul 1999 09:05:05 -0700 (PDT)

> Date: Fri, 23 Jul 1999 12:44:33 -0400
> That makes sense.
> Still, since it is not possible to have multiple "DELEGATED-FROM" 
> parameters, two Attendees could not both delegate to the same 
> Attendee.  Is this a resonable restriction  or should the "ATTENDEE"
> property be allowed to contain multiple "DELEGATED-FROM" parameters?

Another way to solve the problem.

	ATTENDEE;...;delegated-to="mailto:User2@somehost":User1@somehost
	ATTENDEE;...;delegated-to="mailto:User2@somehost":User3@somehost
	ATTENDEE;...;User2@somehost

'User1' and 'User3' can delegate to 'User2'.  And 'User2' can be both
a paramater value in the first and second, and a property value in the
third.

And I don't see a problem with multiple 'DELEGATED-FROM' paramaters.

	ATTENDEE;...;delegated-from="mailto:User1@somehost"
	 ;delegated-from="mailto:User3@somehost"
	 :User2@somehost

-Doug

---

From: [email-masked]
Date: Mon, 26 Jul 1999 17:15:08 GMT

>                ATTENDEE;...;User2@somehost

I think you meant "ATTENDEE;...:User2@somehost
===============================^==============

> And I don't see a problem with multiple 'DELEGATED-FROM' paramaters.

Check the ABNF. It is not allowed. You must specify a list of delegator 
values on a single "DELEGETED-FROM" parameter.

---

From: [email-masked]
Date: Mon, 26 Jul 1999 17:19:29 GMT

>I don't remember and can't find any restriction that limits the number
>of parameters for DELEGATED-FROM or DELEGATED-TO.
>
>There are more parameters that are allowed multiple times because the
>draft does not say they can not be listed multiple times.  Perhaps
>another ABNF bug?
>
>I simply thought this was a way of listing multiple instances.

Not a ABNF bug. See section "4.2.4 Delegators". The ABNF says:

     delfromparam       = "DELEGATED-FROM" "=" DQUOTE cal-address DQUOTE
                          *("," DQUOTE cal-address DQUOTE)

Clearly, you can specify multiple delegators on a single "ATTENDEE" 
property but they have to be a list value on a single "DELEGATED-FROM" 
parameter. 
Hope this is clear.
-- Frank