nishant nishant - 3 months ago 22
JSON Question

How to use dependencies in JSON schema (draft-04)

The rest service response I am working with is similar to following example, I have only included 3 fields here but there are many more:

{
"results": [
{
"type": "Person",
"name": "Mr Bean",
"dateOfBirth": "14 Dec 1981"
},
{
"type": "Company",
"name": "Pi",
"tradingName": "Pi Engineering Limited"
}
]
}


I want to write a JSON schema file for above (draft-04) which will explicitly specify that:

if type == Person then list of required properties is ["type", "name", "dateOfBirth", etc]
OR
if type == "Company" then list of required properties is ["type", "name", "tradingName", etc]


However am unable to find any documentation or example of how to do it.

Currently my JSON schema looks like following:

{
"$schema": "http://json-schema.org/draft-04/schema",
"type": "object",
"required": ["results" ],
"properties": {
"results": {
"type": "array",
"items": {
"type": "object",
"required": ["type", "name"],
"properties": {
"type": { "type": "string" },
"name": { "type": "string" },
"dateOfBirth": { "type": "string" },
"tradingName": { "type": "string" }
}
}
}
}
}


Any pointers/examples of how I should handle this.

Answer

I think the recommended approach is the one shown in Json-Schema web, Example2. You need to use an enum to select schemas "by value". In your case it would be something like:

{
    "type": "object",
    "required": [ "results" ],
    "properties": {
        "results": {
            "type": "array",
            "items": {
                "oneOf": [
                    { "$ref": "#/definitions/person" },
                    { "$ref": "#/definitions/company" }
                ]
            }
        }
    },
    "definitions": {
        "person": {
            "properties": {
                "type": { "enum": [ "person" ] },
                "name": {"type": "string" },
                "dateOfBirth": {"type":"string"}
            },
            "required": [ "type", "name", "dateOfBirth" ],
            "additionalProperties": false
        },
        "company": {
            "properties": {
                "type": { "enum": [ "company" ] },
                . . . 
            }        
        }
    }
}
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