Swagger 2: use enum reference in query parameter of array type

Question

Can not get how to use reference of string type with enum values in array parameter. I can make reference in items key and it is working, but Swagger produce error: Not a valid

Answer 1

Array parameters with items containing $ref are not supported in OpenAPI/Swagger 2.0. But it looks like this will be possible in the next version, 3.0. For now there are a couple of workarounds, see below.

Your spec also has some other issues:

• in: origin is not valid. The in keyword specifies the parameter location (path, query, header, etc.) and only accepts certain values as per the OpenAPI/Swagger spec. I guess you meant in: query or in: header.

• Typos (or copy-paste errors?): swagger: '2.0': has an extra : at the end and collectionFormat: pipes' has an extra ' at the end.

One solution for having an array parameter containing enum values is to define the enum inline:

      parameters:
        - in: query
          name: status
          description: Origin
          required: false
          type: array
          collectionFormat: pipes
          items:
            type: string
            enum:
              - one
              - two

Another solution (found here) is to use YAML anchors to reference the enum. This is a feature of YAML where you can mark a key with &anchor-name and then further down use *anchor-name to reference that key's value.

definitions:
  Origin:
    type: string
    description: Campaign origin
    enum: &origin
      - one
      - two

paths:
  /test:
    get:
      parameters:
        - in: query
          name: status
          description: Origin
          required: false
          type: array
          collectionFormat: pipes
          items:
            type: string
            enum: *origin