SAP CAP: CDS Action with nullable array parameter

[ckuczera]

Dear Community,

I am implementing a Node.js CAP CDS Service based on an interface definition provided and specified by SAP. The interface definition requires an entity action with following parameter:

• code: String
• comment: String
• reasonCode: String
• parameters: array of Object with following attributes:
  • code: String
  • value: String

According to that we have specified the action in the cds file:

The metadata is generated as

So far everything is working as expected, but the interface defintion specifies the "parameters" as nullable and provides an example executing the action as:

When performing an action without a "parameters" value the odata v4 logic is raising an error:

Deserialization Error: Parameter 'parameters' is not nullable.

Raised in:

I have not found a way to mark the parameter as nullable. Did I miss something?

Thanks

[RalfHandl · Accepted solution]

For an array parameter "nullable" controls whether the array may contain null values as in

"parameter": [some-object, null, another-object]

The parameter still has to be provided in the action call.

What "interface definition" are you referring to?

[ckuczera · Accepted solution]

Hi @RalfHandl , thanks for your reply. I am reffering to the taskcenter 3rd party API which requires the parameters to be optional:

https://community.sap.com/t5/sap-builders-blog-posts/sap-task-center-s-new-3rd-party-integration/ba-...

Please checkout chapter 5.1.1.5. Performing Operations on Tasks

I decided to implement that interface using cap, but it seems that this optional part is not feasible with cap

The rest of the required interface objects is feasible using cap

[RalfHandl · Accepted solution]

You can make action parameters optional by annotating them, for example

action foo(

         param: array of String @Core.OptionalParameter : { $Type : 'Core.OptionalParameterType' }

       ) returns String;

[RalfHandl · Accepted solution]

Then you can omit the annotated parameter from the action request body.

I've tested this with the latest CAP for Node.js.

[ckuczera · Accepted solution]

Hello @RalfHandl,

after applying the annotation and updating to the newest cap version 8.1.0 the parameter ist marked as optional.

action action(

    code: String,

    comment: String,

    reasonCode: String,

    @Core.OptionalParameter : { $Type : 'Core.OptionalParameterType' }

    parameters: array of customCodes

) returns tasks;

Thank you very much for your support