刪除默認值（陽）葉

說我有這個刪除默認值（陽）葉

container c { 
    leaf l1; 
    leaf l2 (default 'abcd'); 
}

，我這樣做（restconf）：

DELETE/C/L2

什麼是預期的行爲服務器？是

「刪除葉數據」或
「不要刪除，但保留與默認值葉」發出刪除後

，什麼是對預期的結果GET

GET /c 
c { 
    l1 : 100 // for ex 
    l2 : 'abcd' 
}

來源

2017-01-09 user19937

這在RFC7950, Section 7.6.1描述：

The default value of a leaf is the value that the server uses if the 
leaf does not exist in the data tree. The usage of the default value 
depends on the leaf's closest ancestor node in the schema tree that 
is not a non-presence container (see Section 7.5.1): 

    o If no such ancestor exists in the schema tree, the default value 
    MUST be used. 

    o Otherwise, if this ancestor is a case node, the default value MUST 
    be used if any node from the case exists in the data tree or the 
    case node is the choice's default case, and if no nodes from any 
    other case exist in the data tree. 

    o Otherwise, the default value MUST be used if the ancestor node 
    exists in the data tree. 

In these cases, the default value is said to be in use. 

Note that if the leaf or any of its ancestors has a "when" condition 
or "if-feature" expression that evaluates to "false", then the 
default value is not in use. 

When the default value is in use, the server MUST operationally 
behave as if the leaf was present in the data tree with the default 
value as its value. 

If a leaf has a "default" statement, the leaf's default value is the 
value of the "default" statement. Otherwise, if the leaf's type has 
a default value and the leaf is not mandatory, then the leaf's 
default value is the type's default value. In all other cases, the 
leaf does not have a default value.

在你的情況c是一個不存在的容器，因此在上面踢的第一顆子彈，這意味着您的默認將被使用，如果你刪除的數據樹上相應的葉（是的，你可以刪除它）。因此，服務器必須在操作上表現得如同葉子一樣存在，並且葉子必須具有指定的默認值。

使用哪個協議進行操作並不重要。

對於RESTCONF和GET，該行爲在Section 3.5.4描述：

RESTCONF requires that a server report its default handling mode (see 
Section 9.1.2 for details). If the optional "with-defaults" query 
parameter is supported by the server, a client may use it to control 
retrieval of default values (see Section 4.8.9 for details). 

If a leaf or leaf-list is missing from the configuration and there is 
a YANG-defined default for that data resource, then the server MUST 
use the YANG-defined default as the configured value. 

If the target of a GET method is a data node that represents a leaf 
or leaf-list that has a default value, and the leaf or leaf-list has 
not been instantiated yet, the server MUST return the default 
value(s) that are in use by the server. In this case, the server 
MUST ignore its basic-mode, described in Section 4.8.9, and return 
the default value. 

If the target of a GET method is a data node that represents a 
container or list that has any child resources with default values, 
for the child resources that have not been given value yet, the 
server MAY return the default values that are in use by the server, 
in accordance with its reported default handing mode and query 
parameters passed by the client.

所以，你的GET例如可能會或可能不正確，這取決於默認的處理模式有效，因爲上面的最後一段提示。

來源

2017-01-10 08:00:50 predi

刪除默認值（陽）葉

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