How to limit my swagger definition array to be either 0 or 3

Question

I have my swagger definition like :

someDef:
    type: object
    properties:
      enable:
        type: boolean
        default: false
      nodes:
        type: array
        maxItems: 3
        items:
          type: object
          properties:
            ip:
              type: string
              default: ''

My nodes are array and it has maxitems: 3. I want my nodes items length to be either 0 or 3. Thanks in advance.

Lavonna

Answer 1

"Either 0 or 3 items" can be defined in OpenAPI 3.x (openapi: 3.x.x) but not in OpenAPI 2.0 (swagger: '2.0').

OpenAPI 3.x

You can use oneOf in combination with minItems and maxItems to define the "either 0 or 3 items" condition:

# openapi: 3.0.0

nodes:
  type: array
  items:
    type: object
    properties:
      ip:
        type: string
        default: ''
  oneOf:
    - minItems: 0
      maxItems: 0
    - minItems: 3
      maxItems: 3

Note while oneOf is part of the OpenAPI 3.0 Specification (i.e. you can write API definitions that include oneOf), actual tooling support for oneOf may vary.

OpenAPI 2.0

OAS 2 does not have a way to define "either 0 or 3 items". The most you can do is to use maxItems: 3 to define the upper limit.

Pollywog