Re: [netconf] FW: [netmod] CRUD operations on Leaf-list in RFC8040

Hi,

The RESTCONF target resource has to be one resource.
The WG added YANG Patch (RFC 8072) to do more complex editing operations.

Andy

On Wed, Sep 25, 2019 at 7:57 AM Qin Wu <bill.wu@huawei.com> wrote:

>
> Send to netconf for discussion in the right place,thank Jurgen for kindly
> reminder.
>
>
> *发件人： *Qin Wu<bill.wu@huawei.com>
> *收件人： *netmod<netmod@ietf.org>
> *抄送： *Zengjuan<annette.zeng@huawei.com>
> *主题： *[netmod] CRUD operations on Leaf-list in RFC8040
> *时间： *2019-09-25 19:55:12
>
> Hi, All:
>
> During implementing RFC8040, we face a few problems related to leaf-list
> usage.
>
> I am wondering how do we create multiple instance of leaf-list data
> resource?
>
> Suppose we have example-foo.yang model as follows:
>
> example-top.yang
>
>
>
>    container top {
>
>     list list1 {
>
>         key "key1 key2 key3";
>
>          ...
>
>          list list2 {
>
>              key "key4 key5";
>
>              ...
>
>              leaf X { type string; }
>
>          }
>
>      }
>
>      leaf-list Y {
>
>        type uint32;
>
>      }
>
> }
>
> To create a new "Y" resource within the "top" resource, can we make
>
> the client send the following request:
>
> POST /restconf/data/example-top:top HTTP/1.1
>
> Host: example.com
>
> Content-Type: application/yang-data+json
>
>
>
> {
>
>   "example-top:Y" : [value1,value2]
>
> }
>
>
>
> response：
>
> HTTP/1.1 201 Created
>
> Date: Thu, 26 Jan 2017 20:56:30 GMT
>
> Server: example-server
>
> Location:
> https://example.com/restconf/data/example-top:top/Y=value1&value2
>
> Last-Modified: Thu, 26 Jan 2017 20:56:30 GMT
>
> ETag: "b3830f23a4c"
>
>
>
> Also I don’t understand why we add limitation to PUT method and plain
> patch method on leaf-list and don’t allow
>
> The value of leaf-list instance to be changed by these two methods
>
> see section 4.5 and section 4.6.1
>
> “
>
> 4.5.  PUT
>
>    If the target resource represents a YANG leaf-list, then the PUT
>
>    method MUST NOT change the value of the leaf-list instance.
>
> 4.6.1..  Plain Patch
>
>    If the target resource represents a YANG leaf-list, then the PATCH
>
>    method MUST NOT change the value of the leaf-list instance.
>
> “
>
> Suppose I want to delete all leaf-list instance values associated with
> leaf-list "Y",
>
> Can I send the following request:
>
> DELETE /restconf/data/example-top:top/Y  HTTP/1.1
>
> Host: example.com
>
>
>
> Quoted section 4.7:
>
> “
>
> 4.7.  DELETE
>
>    If the target resource represents a configuration leaf-list or list
>
>    data node, then it MUST represent a single YANG leaf-list or list
>
>    instance.  The server MUST NOT use the DELETE method to delete more
>
>    than one such instance.
>
> ”
>
> It seems obvious that DELETE method can not delete more than one
> instances. But I don’t know why?
>
>
>
> Also I don’t know we add constraint on XML encoding in the Get request, only allow one single element be
>
> returned for XML encoding, see section 4.3 of RFC8040 as follows:
>
> “
>
> 4.3.  GET
>
>    If a retrieval request for a data resource representing a YANG
>
>    leaf-list or list object identifies more than one instance and XML
>
>    encoding is used in the response, then an error response containing a
>
>    "400 Bad Request" status-line MUST be returned by the server.
>
> “
>
> Suppose I want to retrieve/delete/modify multiple leaf-list instance data
> resource, can I wrap leaf-list "Y" within container "top",
>
> create/delete/modify container "top" data resource?
>
> “
>
> Comments?
>
>
>
> -Qin
>
>
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