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ietf-netmod-yangietf-restconf

accessing a specific leaf-list entry using yang restconf


It is clear to me how to refer to a list item (restconf draft) but it is not clear how to refer to a specific leaf-list entry. For example, given the following definition:

module x { 
   container y { 
     leaf-list z;
   }
}

and if I have the following data in the system

<y>
  <z>a</z>
  <z>b</z>
  <z>d</z>
</y>

how do I insert a c in the third position ?

Restconf has the 'insert' and 'point' that takes the resource uri. But, what is the resource uri to identify a leaf-list item ? If I want to refer to the second entry, is the following valid ?

/y/z=b

Solution

  • Each leaf-list entry is a separate data resource in restconf-draft-10.

    Containers, leafs, leaf-list entries, list entries, anydata and anyxml nodes are data resources.

    This is what Section 3.5 says about leaf-list entries. Further it defines encoding of leaf-list Data Resource Identifiers in 5.3.1:

    If a data node in the path expression is a YANG leaf-list node, then the leaf-list value MUST be encoded according to the following rules:

    o The instance-identifier for the leaf-list MUST be encoded using one path segment [RFC3986].

    o The path segment is constructed by having the leaf-list name, followed by an "=" character, followed by the leaf-list value. (e.g., /restconf/data/top-leaflist=fred).

    So, your example for second entry it would be: /restconf/data/x:y/z=b.

    As for inserting, it seems to be unclear. There are examples in the appendix D of the draft for both point and insert, but use a list instead of a leaf-list (note that both MUST be ordered-by user in order for the two parameters to be valid in a request).

    D.3.5. "point" Parameter

      POST /restconf/data/example-jukebox:jukebox/
          library/artist=Foo%20Fighters/album=Wasting%20Light?
          insert=after&point=%2Fexample-jukebox%3Ajukebox%2F
          library%2Fartist%3DFoo%20Fighters%2Falbum%3D
          Wasting%20Light%2Fsong%3DBridge%20Burning   HTTP/1.1
      Host: example.com
      Content-Type: application/yang.data+json
    
      {
        "example-jukebox:song" : {
          "name" : "Rope",
          "location" : "/media/foo/a7/rope.mp3",
          "format" : "MP3",
          "length" : 259
        }
      }