Re: [netconf] restconf collections

Kent Watsen <kent+ietf@watsen.net> Wed, 30 September 2020 17:33 UTC

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From: Kent Watsen <kent+ietf@watsen.net>
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Date: Wed, 30 Sep 2020 17:33:41 +0000
Cc: Qin Wu <bill.wu@huawei.com>, Andy Bierman <andy@yumaworks.com>, "netconf@ietf.org" <netconf@ietf.org>
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To: Robert Varga <nite@hq.sk>
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Subject: Re: [netconf] restconf collections
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Hi Robert,

> That is assuming the list in question has iteration order which is
> stable. I do not believe this is something RFC7950 mandates on anything
> except ordered-by=user.

If not “ordered-by user”, then its “ordered-by system” that, as RFC 7950 says, "the server is free to sort the list entries in any reasonable order.”  This is a stable ordering, IMO.



> So let's say the list has 4 elements A, B, C, D.
> 
> 1) The first request returns items A, B, C.
> 2) An item is inserted before C, so that the list is E, A, B, C, D.
> 3) What does the second request return?
> 
> Similarly:
> 
> 1) The first request returns items A, B, C.
> 2) An item is deleted before C, so that the list is B, C, D.
> 3) What does the second request return?
> 
> Pagination is deceptively hard.

Is your conjecture that the solution should enable something akin to cursors?  Would this be an advanced feature that a server might support on a list-by-list basis?   Maybe "node-tags” could be useful here too…

K.