Re: [VCARDDAV] [EAI] Internationalized email addresses in vCard 4.0

[John C Klensin <[e-mail]>]

--On Friday, 05 November, 2010 09:55 -0400 Simon Perreault
<[e-mail]> wrote:

> Hello,
> 
> We need some advice from the EAI working group.
> 
> vCard 4.0 is a file format for contact information. It's a
> textual format and its character set is always UTF-8. One of
> the information items it may contain is email addresses. See
> here:
> http://tools.ietf.org/html/draft-ietf-vcarddav-vcardrev-13#sec
> tion-6.4.2
> 
> Basically to list an email address in a vCard you will have a
> line looking like this:
> 
> EMAIL:[e-mail]
> 
> The ABNF for what comes after the colon is "addr-spec", which
> is defined in RFC 5322, section 3.4.1.
> 
> Now, addr-spec does not allow full Unicode. An
> internationalized address would need to be EAI/IDN-encoded,
> which implies that a vCard app would need to decode it to
> display it to a user.

Except that you misunderstand what "EAI/IDN encoding". I would
strongly suggest that you have a look at the EAI drafts and that
you deal with this by replacing the 5322 addr-spec with the EAI
equivalent.  Otherwise, you are just going to create trouble for
yourselves and your users.

> Questions:
> - Is this the right way to do it?

Nope.  See above.

> - Should we allow full Unicode, which removes the need for
> decoding from the vCard app and adds the need for encoding in
> the MUA?

No, and you are asking the wrong question.  See above.

> - Should both forms be possible, should one form be
> preferred over the other, or should only one form be allowed?

What "both forms"?

> - What should the ABNF look like for allowing Unicode
> characters in email addresses?

See above.  Your one problem is that you will end up with a
normative reference with a spec that isn't finished yet.  The
good news is that I hope and expect to have it wrapped up well
before the end of the calendar year.

> - Would it help us in any way if we were to specify a mailto:
> URL instead?

Arggh.  Translation: certainly not unless you want to wait for
the EAI WG to finish its review of mailto, which has not really
begun yet.

     john