Ladislav Lhotka <[email protected]> wrote: > On Wed, 2018-10-10 at 19:23 -0700, Andy Bierman wrote: > > > > > > On Wed, Oct 10, 2018 at 6:59 PM, Reshad Rahman (rrahman) <[email protected]> > > wrote: > > > On 2018-10-10, 9:59 AM, "netmod on behalf of Martin Bjorklund" < > > > [email protected] on behalf of [email protected]> wrote: > > > > > > Ladislav Lhotka <[email protected]> wrote: > > > > Martin Bjorklund <[email protected]> writes: > > > > > > > > > Hi, > > > > > > > > > > While reviewing restconf-notif, I saw this example: > > > > > > > > > > { > > > > > "ietf-subscribed-notifications:input": { > > > > > "stream": "NETCONF", > > > > > "stream-xpath-filter": "/ds:foo/", > > > > > "dscp": "10" > > > > > } > > > > > } > > > > > > > > > > Note the "stream-xpath-filter". It has a prefix in the XPath > > > string. > > > > > How are prefixes declared when JSON is used? > > > > > > > > > > The leaf "stream-xpath-filter" says: > > > > > > > > > > o The set of namespace declarations are those in > > > scope on > > > > > the 'stream-xpath-filter' leaf element. > > > > > > > > > > (I think I provided that text...) > > > > > > > > > > This assumes that the encoding is XML, or at leas that the > > > encoding > > > > > can somehow transfer namespace declarations. > > > > > > > > It can't. There are two options: > > > > > > > > 1. have different representations of this value in XML and JSON, > > > > analogically to instance indentifiers (sec. 6.11 in RFC 7951). > > > > > > > > 2. use a module name rather than a prefix in XML, too. > > > > > > > > I would suggest #2. > > > <RR> But that means making non-backwards compatible change to the XML > > > representation? > > > > Not really. It means NETMOD WG would be creating its own special variant of > > XPath. > > The thing is that XPath is "XML Path Language", so using it outside XML is > problematic.
Not necessarily. Section 5 of the XPath 1.0 spec defins the "data model" where an XPath expression is applied. We could make a formal specification of how a YANG data tree maps to this data model (pretty straightforward...). I think experience from implementations over the last 8 years show that this in fact works quite well. /martin > > Lada > > > > > > Hmm, so you mean change the leaf "stream-xpath-filter" to say: > > > > > > o The set of namespace declarations has one member for each > > > YANG module supported by the server. This member maps > > > from the YANG module name to the YANG module namespace. > > > > > > This means that in the XPath expression, the module name > > > serves as the prefix. > > > > > > .... and then also give an example of this. > > > > > > This is probably what we need to do in all places where yang:xpath1.0 > > > is used, going forward. Maybe even define a new type > > > yang:xpath1.0-2 (name?) with the set of namespace declarations > > > built-in. > > > > > > We should avoid making off-the-shelf implementations of standards like XPath > > unusable. > > At the very least this should be only available if the server supports it > > (with a capability URI) > > > > > > > <RR> So we need an update to RFC7951? > > > > > > Regards, > > > Reshad. > > > > > > > > > Andy > > > > > /martin > > > > > > > > > > > > > > > > > > > > > > > Lada > > > > > > > > > > > > > > How is this supposed to work with JSON? > > > > > > > > > > > > > > > /martin > > > > > > > > > > _______________________________________________ > > > > > netmod mailing list > > > > > [email protected] > > > > > https://www.ietf.org/mailman/listinfo/netmod > > > > > > > > -- > > > > Ladislav Lhotka > > > > Head, CZ.NIC Labs > > > > PGP Key ID: 0xB8F92B08A9F76C67 > > > > > > > > > > _______________________________________________ > > > netmod mailing list > > > [email protected] > > > https://www.ietf.org/mailman/listinfo/netmod > > > > > > > > > _______________________________________________ > > > netmod mailing list > > > [email protected] > > > https://www.ietf.org/mailman/listinfo/netmod > > > > > -- > Ladislav Lhotka > Head, CZ.NIC Labs > PGP Key ID: 0xB8F92B08A9F76C67 > _______________________________________________ netmod mailing list [email protected] https://www.ietf.org/mailman/listinfo/netmod
