Defining custom JSON schema type

[Donal Murtagh]

Given a JSON schema such as

    {
      "type": "object",
      "properties": {
        "ageInYears": {
          "type": "integer",
          "minimum": 0,
          "maximum": 120
        },
        "spouseAgeInYears": {
          "type": "integer",
          "minimum": 0,
          "maximum": 120
        },
        "childAgeInYears": {
          "type": "integer",
          "minimum": 0,
          "maximum": 120
        }
      }
    }

Notice that the attributes of each property are identical, so to avoid this repetition I'd like to somehow define a custom type

    "age": {
      "type": "integer",
      "minimum": 0,
      "maximum": 120
    }

and then refer to it within my schema, e.g.

    {
      "type": "object",
      "properties": {
        "ageInYears": {
          "type": "age"
        },
        "spouseAgeInYears": {
          "type": "age"
        },
        "childAgeInYears": {
          "type": "age"
        }
      }
    }

It seems that the purpose of the "format" attribute is to implement this sort of type customisation, but I can't find any examples of how to define a custom "format" value.

[Henry Andrews]

Hi Donal,

  You want "definitions" and "$ref":

{
    "definitions": {

        "ageInYears": {
            "type": "integer",
            "minimum": 0,
            "maximum": 120
        }
    },
    "type": "object",
    "properties": {

        "ageInYears": {"$ref": "#/definitions/ageInYears"},
        "spouseAgeInYears": {"$ref": "#/definitions/ageInYears"},
        "childAgeInYears": {"$ref": "#/definitions/ageInYears"}
    }
}

Custom formats are more for things that can't be fully described in schema, which is why they are more about semantics than structure.

thanks,

-henry