[netconf] Guidelines for YANG anyxml/anydata statements in RFC8040 (Restconf)

[Henning Rogge <[e-mail]>]

Hi,

I have some trouble with the anyxml/anydata YANG statements in
Restconf... to be more precise in a Restconf-server that accepts both
XML and JSON transport encoding.

The anydata issue is that there are some "data resources" that have
the same XML transport encoding but different JSON encoding. Which
means I cannot "guess" the YANG schema of incoming XML data for an
anyxml statement.

If I read RFC 7950 and 7951 correctly, then a (as an example)
leaf-list with a single entry has the same encoding in XML as a leaf
of the same name... but not in JSON. Same is true for a list with one
element and a container.

The problem with anyxml is the same and worse... RFC 7951 section 5.6
demands transporting the data encoded in JSON (and not in a string
that contains the XML data), but does not define how to encode the XML
data into JSON and the other way around.

Are there any guidelines/best-practices for this problem?

Thanks

Henning Rogge