Re: [netmod] xpath expressions in JSON

Qin Wu <bill.wu@huawei.com> wrote:
> -----邮件原件-----
> 发件人: netmod [mailto:netmod-bounces@ietf.org] 代表 Ladislav Lhotka
> 发送时间: 2018年10月10日 20:41
> 收件人: Martin Bjorklund; netmod@ietf.org
> 主题: Re: [netmod] xpath expressions in JSON
> 
> Martin Bjorklund <mbj@tail-f.com> 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).
> 
> [Qin]: This has been brought up before:
> https://www.ietf.org/mail-archive/web/netconf/current/msg15501.html

That is a slightly different problem; how to represent an
*instance-identifier* in a RESTCONF URL.

/martin

> 
> 2. use a module name rather than a prefix in XML, too.
> 
> I would suggest #2.
> 
> Lada
> 
> >
> > How is this supposed to work with JSON?
> >
> >
> > /martin
> >
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> 
> --
> Ladislav Lhotka
> Head, CZ.NIC Labs
> PGP Key ID: 0xB8F92B08A9F76C67
> 
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