Re: [netconf] Trouble with RFC 8040 (Restconf) fields Query Parameter

Kent Watsen <kent+ietf@watsen.net> Fri, 08 May 2020 18:49 UTC

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From: Kent Watsen <kent+ietf@watsen.net>
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Date: Fri, 08 May 2020 18:49:08 +0000
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To: Henning Rogge <hrogge@gmail.com>, Mahesh Jethanandani <mjethanandani@gmail.com>
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Subject: Re: [netconf] Trouble with RFC 8040 (Restconf) fields Query Parameter
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Hi Henning,

>> hmm, when reading through them I noticed something... is
>> fields=uuid;actual-equipment(manufactured-thing(equipment-type);structure)
>> even valid?
>> 
>> According to the RFC8040 4.8.3. the bracket part of the expression can
>> only nest in the last of the fields...
>> 
>> 'path ; fields-expr', but not 'fields-expr ; path”
> 
> I will let one of the authors comment on what the intent was.

This is likely an errata in just the ABNF.

Supporting this view, note that fields=genre;year == fields=year;genre (i.e., order doesn't matter)


>> What do you think ? I guess this was don to prevent a whole tree of
>> field subexpressions... the ABNF does only seem to support a "line" of
>> them.
> 
> The implementation in ODL does not care what order the query is placed in. Even if the bracket part of the query is placed in the last field, when it builds up the hash index for the search, the bracketed parts can appear anywhere based on how it gets hashed.

A reasonable application of Postel's principle.


Kent // as a co-author and quasi-instigator of the sub-select syntax