[Ietf-caldav] Dead properties on CalDAV events / folders

[Helge Hess]

On 16. Dez 2005, at 19:52 Uhr, Wilfredo Sánchez Vega wrote:
> If you say that a server MUST not modify X- properties then you are  
> removing the flexibility on the server side that you are requesting  
> on the client side.

It must not delete/touch unknown X- properties, it might modify the  
set of X- properties or change X- properties it knows. This doesn't  
limit the flexibility on the server side.

But it has serious consequences if you choose to do any change to  
PUT'ted entities on the server side. Every subsequent consistent- 
update [etag] request must fail as per HTTP (even if the change is  
just a result of the PUT issued by the client).

Eg a client would show an "someone has changed your item in the  
server" warning / conflict resolution panel prior submitting _any_  
next request. In short: if you want to allow server-side  
modifications, you should specify that a client MUST immediatly reget  
the entity after a change/creation request.

> A server might, for example, want to define some of its own X-  
> properties, or interact with a client or with another server  
> through X- properties in a way that involves updating a property  
> that the client originally set.

Sure. Exactly the same restriction of the server applies to the  
client. It must not modify/delete unknown X- properties and preserve  
them in the next update operation.

(This already works fine with Kontact and Evolution)

Greets,
   Helge
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