Re: [netconf] Question on restconf empty list reply

Thank you for the answer!
What does "the empty lists exists or not" mean, how is an existing empty
list different from a non-existent list wrt YANG? I would think that a
YANG list have instances (= it exists), or it does not have instances (=
is empty = does not exist).

Another related question is how the same request but for XML encoding
should be treated, ie a YANG list x with no elements (empty
list/non-existent)?

  GET /restconf/data/m:x
  Accept: application/yang-data+xml

Is the reply "404 Not Found" status-line and error-tag value
"invalid-value" (following the list resource doe snot exist)
or, following the JSON [] (existing empty list) reasoning, a "204 No
Content"?

Again apologizes for these basic questions,
Regards,
Olof Hagsand

On 2020-02-23 12:28, Schönwälder, Jürgen wrote:
> My reading of RFC 7951 section 5.4 is that an empty list results in an
> empty JSON array. A related question is likely whether the empty list
> exists or not. RFC 8040 says a 404 response indicates that the
> resource does not exist (or is not accessible). So both responses may
> be reasonable, depending on the existence/accessibility of the resource.
> 
> /js
> 
> On Sun, Feb 23, 2020 at 12:12:58PM +0100, Olof Hagsand wrote:
>> Hello,
>> In a restconf GET request of an empty YANG list using JSON encoding,
>> what is the expected reply? I.e. using a yang list "x" in module "m"
>> (pseudo http):
>>   GET /restconf/data/m:x
>>   Accept: application/yang-data+json
>>
>> Is the reply (1):
>>   HTTP/1.1 200 OK
>>   {
>>     "m:x": []
>>   }
>>
>> or should it be (2)
>>   "404 Not Found" status-line and error-tag value "invalid-value"?
>>
>> Apologizes that this is a basic question, and I am sure this is resolved
>> properly, but we have some discussions with users on how to properly
>> interpret the description of GET in RFC 8040 Section 4.3 and RFC 7951.
>>
>> Regards,
>> Olof Hagsand,
>> Clixon maintainer
>>
>> _______________________________________________
>> netconf mailing list
>> netconf@ietf.org
>> https://www.ietf.org/mailman/listinfo/netconf
> 