Re: [Orgmode] .ics export violates RFC2445

[Carsten Dominik]

On Apr 29, 2008, at 7:16 PM, Adam Spiers wrote:

> > > Also, it would be great if a UID field could be generated for each
> > > event, perhaps by checksumming the contents of the event in some  
> > > way.
> > > The RFC says:
> > >
> > > Conformance: The property MUST be specified in the "VEVENT",
> > > "VTODO", "VJOURNAL" or "VFREEBUSY" calendar components.
> > >
> > >   -- http://tools.ietf.org/html/rfc2445#section-4.8.4.7
> > >
> > > The checksum would ensure that the UID field only changes when the
> > > event details check, which would be a first step towards helping
> > > synchronisation systems.  I'm vaguely suspicious that the lack of  
> > > UIDs
> > > currently confuses Google Calendar too.
> >
> > A UID may be good.  However I think changing the UID when changing  
> > the
> > entry would be bad, because this would exactly *disable*  
> > synchronization.
> > To synchronize, you must know which entries to compare, and this is  
> > only
> > possible with a persistent UID.
>
> Doh - you are right of course.
>
> > I guess we could create one, but this UID would then have to be  
> > stored
> > in the entry, as a property.  Exporting to ical again must then re- 
> > use the
> > old uid each time.
> >
> > My org-id.el in the contrib directory allows already to create unique
> > identifiers, and it would be easy enough to include the domain to  
> > make
> > them truely unique, wordwide.
> >
> > However, right now I am hesitating to force a property drawer onto
> > every entry that ever is exported to iCalendar.  But as an option,  
> > this might
> > really be good and eventually allow true synchronization.
>
> I understand your hesitation - as an option that sounds perfect.

Please get the latest GIT version of Org.  Then set the variable

(setq org-icalendar-force-UID t)

and try to export to iCalendar.

Right now, I am only forcing and using the ID for VEVENT.  I am not  
using it for VTODO, because I am not sure if it is allowed to have the  
same UID for a VEVENT and a VTODO, if they originate from the same  
entry in a database?  Do you or anyone else know what the rules are  
for this?

- Carsten