Deserializing JSON nulls with allowNullAsDefault

By default, Genero Web Services JSON to Genero BDL deserialization will raise errors if the JSON content does not match the BDL variable receiving the data. For example, you have a Genero BDL record defined as follows:

TYPE tAddress RECORD
    street STRING,
    city STRING,
    state STRING,
    zip STRING
END RECORD

TYPE tCustomer RECORD
    id STRING,
    name STRING,
    address tAddress
END RECORD

The following JSON document will by default raise conversion errors because the "address" element is defined as "null", which does not correspond with the BDL variable:

{
  "id": "1",
  "name": "John Doe",
  "address": null
}

To avoid the conversion error, set the following option to allow nulls in your server module:

CALL json.Serializer.setOption( "allowNullAsDefault", 1 )

Alternatively, it is recommended that you define BDL variables with the attributes value json_null="null" to handle JSON serialization of null values.

TYPE tAddress RECORD ATTRIBUTES(json_null="null")
    street STRING,
    city STRING,
    state STRING,
    zip STRING
END RECORD

For more information and examples using json_null, go to NULLs and empty structures.