JSON Schema conditional: field is required based on value of another field

Question

I'm trying to implement this condition: field is required based on value of another field i.e. if request with "index":"true" exists then "id" element required: true.

Here is a sample schema:

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "title": "test title",
  "type": "object",
  "properties": {
    "data": {
      "type": "array",
      "items": {
        "$ref": "#/definitions/Item"
      },
      "minItems": 0
    }
  },
  "required": [
    "data"
  ],
  "definitions": {
    "Item": {
      "type": "object",
      "properties": {
        "id": {
          "type": [
            "integer",
            "string"
          ]
        },
        "type": {
          "type": "string"
        }
      }
    }
  }
}

How it can be implemented?

Any pointers will be helpful.

Answer 1

Your sample chema is strange for me, but for validation case in ticket description your can use this part of json shema:

"properties": {
    "data": {
        "oneOf": [
            {
                "type": "object",
                "required": [
                    "index"
                ],
                "properties": {
                    "index": {
                        "type": "boolean",
                        "enum": [false]
                    }
                }
            },
            {
                "type": "object",
                "required": [
                    "index",
                    "id"
                ],
                "properties": {
                    "index": {
                        "type": "boolean",
                        "enum": [true]
                    },
                    "id": {
                        "type": "boolean"
                    }
                }
            }
        ]
    }
}

This trick helps for you, if you want validate one parameter, when other parameters equals to some value.