nxcals.api.common.utils.array_utils.StructType.fromJson

classmethod StructType.fromJson(json: Dict[str, Any]) → StructType

Constructs StructType from a schema defined in JSON format.

Below is a JSON schema it must adhere to:

 {
   "title":"StructType",
   "description":"Schema of StructType in json format",
   "type":"object",
   "properties":{
      "fields":{
         "description":"Array of struct fields",
         "type":"array",
         "items":{
             "type":"object",
             "properties":{
                "name":{
                   "description":"Name of the field",
                   "type":"string"
                },
                "type":{
                   "description": "Type of the field. Can either be
                                   another nested StructType or primitive type",
                   "type":"object/string"
                },
                "nullable":{
                   "description":"If nulls are allowed",
                   "type":"boolean"
                },
                "metadata":{
                   "description":"Additional metadata to supply",
                   "type":"object"
                },
                "required":[
                   "name",
                   "type",
                   "nullable",
                   "metadata"
                ]
             }
        }
     }
  }
}

Parameters:

json (dict or a dict-like object e.g. JSON object) – This “dict” must have “fields” key that returns an array of fields each of which must have specific keys (name, type, nullable, metadata).

Return type:

StructType

Examples

>>> json_str = '''
...  {
...      "fields": [
...          {
...              "metadata": {},
...              "name": "Person",
...              "nullable": true,
...              "type": {
...                  "fields": [
...                      {
...                          "metadata": {},
...                          "name": "name",
...                          "nullable": false,
...                          "type": "string"
...                      },
...                      {
...                          "metadata": {},
...                          "name": "surname",
...                          "nullable": false,
...                          "type": "string"
...                      }
...                  ],
...                  "type": "struct"
...              }
...          }
...      ],
...      "type": "struct"
...  }
...  '''
>>> import json
>>> scheme = StructType.fromJson(json.loads(json_str))
>>> scheme.simpleString()
'struct<Person:struct<name:string,surname:string>>'