Re: [VCARDDAV] How to encode X-Properties in XML?

[Simon Perreault <[e-mail]>]

On 2010-03-30 00:13, Joe Hildebrand wrote:
> - In the XML format, any child of<vcard>  in the default namespace gets
> translated to a text property.  X-, VND-, and
> newly-registered-but-not-yet-supported-in-your-software elements all fall
> into this category.  Unfortunately, it appears that we need to upcase in the
> XML-to-text direction

In text vCard, properties are case-insensitive. So no need to upcase in 
this direction.

But as was already mentioned, property names are limited to
[a-zA-Z0-9-].

> - In the XML format, any child of<vcard>  in a namespace other than the
> default gets turned into XML: in the text format.  Even if it is
> standardized.

Right.

> - In the text format, XML: properties always get directly transliterated
> into XML as children of<vcard>.  This means they MUST have a namespace
> other than the default.  If they don't, we can specify what happens, but the
> list of things I've thought of are: 1) error, and fail translation 2) warn,
> and don't copy the XML: property 3) warn, and change the namespace to some
> specified warning namespace 4) do 3 silently 5) copy the element as-is.
>
> I don't like 5, because the element won't round-trip back to text format the
> same way.  3 or 4 sound fine to me, but I could live with 2 or even 1.

I'd rather follow Postel's principle.

- On output, the element in XML: MUST have a namespace, and it MUST NOT 
be the vCard 4 namespace.

- On input, the content of the XML: property MUST be interpreted as a 
single XML element.

That's it. Whether implementations output warnings or not is out of 
scope (some could even not have the capability of outputting warnings).

> - Text format properties that are not currently in the XML definition (such
> as X-, VND-, and new-but-iana-registered) are unlikely to ever have any
> interesting structure in XML.  The best we can do is specify syntactic
> transformations that survive round trips.  As a consequence, we might
> consider suggesting that ALL new properties SHOULD be defined in XML format
> going forward, with XML: being their native representation in the text
> format.

+0.5

The problem is that these new properties would be in the vCard 4 
namespace, and we said that no element in this namespace can appear as 
the content of the XML property.

> - Do we specify what happens to \n in text format, when translated?  Does it
> stay \n, or get translated to CRLF?  What about wrapped lines?  Do they get
> unwrapped?  My preference would be unwrap and translate to \n to CRLF.

We have this currently:

                                                               The chunk
       is subject to normal line folding and escaping, i.e. replace all
       backslashes with "\\", then replace all newlines with "\n", then
       fold long lines.

Can you suggest text to be added?

Thanks,
Simon
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