How to represent inaccessible data for property?

JenHuang
Minnow

Posts: 23

How to represent inaccessible data for property? Dec 24, 2020 7:13:54 GMT

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Post by JenHuang on Dec 24, 2020 7:13:54 GMT

As I checked how to represent the inaccessible data for property?
It is very clear for the string and represent by null, but if type is "boolean", "integer", "number", how to represent it?

DSP 0266 Redfish Specification, 10.5 Properties
If an implementation supports a property, it shall always provide a value for that property. If a value is unknown at the time of the operation, due to an internal error, the current resource state, or inaccessibility of the data,
then the value of null is an acceptable value if supported by the schema definition.

mraineri
Administrator

Posts: 1,132

How to represent inaccessible data for property? Jan 4, 2021 14:06:17 GMT

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Post by mraineri on Jan 4, 2021 14:06:17 GMT

In the different schema languages, a property that can be null is expressed by:

CSDL: the property definition will not have the term Nullable="false".
JSON Schema: the "type" term will contain "null" in the list.
OpenAPI: the nullable term will be set to true.

In cases where null isn't allowed for a property, usually the forum doesn't expect the data to ever not be available. However, we have added null as an allowable type to properties over time as we've seen cases where a service might not know the value.

Do you have a specific property and scenario in mind that we can discuss further?

JenHuang
Minnow

Posts: 23

How to represent inaccessible data for property? Jan 6, 2021 15:49:38 GMT

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Post by JenHuang on Jan 6, 2021 15:49:38 GMT

For more detail with my problem, I checked as the following description from redfish specification.

If a value is unknown at the time of the operation, due to an internal error, the current resource state, or inaccessibility of the data then the value of null is an acceptable value if supported by the schema definition.

General speak, all property might have trouble for internal error and there is only `null` for string. (my case is NTPServers, type is array)
redfish.dmtf.org/schemas/v1/ManagerNetworkProtocol.v1_6_1.json

How to represent the data if internal error for other data type except string?

Last Edit: Jan 6, 2021 15:52:51 GMT by JenHuang

mraineri
Administrator

Posts: 1,132

How to represent inaccessible data for property? Jan 6, 2021 17:32:56 GMT

Quote

Post by mraineri on Jan 6, 2021 17:32:56 GMT

NTPServers does allow for null to be used in the array. The property itself cannot be null (OData does not allow for this), but the values in the array can be null.

So, if you had some sort of internal error getting your NTPServers, you can do something like this:

"NTPServers": [
    null,
    null,
    null
]

It would also be good to use the @message.ExtendedInfo annotation in your response to indicate the error conditions encountered.