How to define the min size of array in the json schema

Question

I want to make a schema of json file.It's for an array of products.

The json schema is similar as below:

{
"$schema": "http://json-schema.org/draft-04/schema#",
"title": "Product set",
"type": "array",
"items": {
    "title": "Product",
    "type": "object",
    "properties": {
        "id": {
            "description": "The unique identifier for a product",
            "type": "number"
        },
        "name": {
            "type": "string"
        },
        "price": {
            "type": "number",
            "minimum": 0,
            "exclusiveMinimum": true
        },
        "tags": {
            "type": "array",
            "items": {
                "type": "string"
            },
            "minItems": 1,
            "uniqueItems": true
        },
        "dimensions": {
            "type": "object",
            "properties": {
                "length": {"type": "number"},
                "width": {"type": "number"},
                "height": {"type": "number"}
            },
            "required": ["length", "width", "height"]
        },
        "warehouseLocation": {
            "description": "Coordinates of the warehouse with the product",
            "$ref": "http://json-schema.org/geo"
        }
    },
    "required": ["id", "name", "price"]
}
}

The array should at least one item in it. How can I define the minimum of the array?

Do I need to add the minimun defination?

Answer 1

To set the minimum # of item in an array, use the "minItems".

See:

http://tools.ietf.org/html/draft-fge-json-schema-validation-00#section-5.3.3

and

http://jsonary.com/documentation/json-schema/?section=keywords/Array%20validation

   {
   "$schema": "http://json-schema.org/draft-04/schema#",
   "title": "Product",
   "description": "A product from Acme's catalog",
   "type": "object",
   "properties": {
      ...
      "tags": {
          "type": "array",
          "items": {
              "type": "string"
          },
          "minItems": 1,
          "maxItems": 4,
          "uniqueItems": true
      }
  },
  "required": ["id", "name", "price"]
  }