How to specify a property can be null or a reference with swagger

问题

How to specify a property as null or a reference? discusses how to specify a property as null or a reference using jsonschema.

I'm looking to do the same thing with swagger.

To recap the answer to the above, with jsonschema, one could do this:

{
   "definitions": {
      "Foo": {
         # some complex object
      }
   },

   "type": "object",
   "properties": {
      "foo": {
         "oneOf": [
            {"$ref": "#/definitions/Foo"},
            {"type": "null"}
         ]
      }
   }
}

The key point to the answer was the use of oneOf.

The key points to my question:

I have a complex object which I want to keep DRY so I put it in a definitions section for reuse throughout my swagger spec: values of other properties; response objects, etc.
In various places in my spec a property may be a reference to such an object OR be null.

How do I specify this with Swagger which doesn't support oneOf or anyOf?

Note: some swagger implementations use x-nullable (or some-such) to specify a property value can be null, however, $ref replaces the object with what it references, so it would appear any use of x-nullable is ignored.

回答1:

Not easy to do that. Even almost impossible. Your options :

Wait

There is a very long discussion about this point, maybe one day it will be done...

Use vendors extensions

You can use vendors extensions like x-oneOf and x-anyOf. I have already taken this hard way: You must to upgrade all used 'swagger tools' to take into account these vendors extensions.

In my case, we needed 'only' to :

Develops our own Jax-RS parser with customized annotations in order to extract swagger API file from sources
Extends swagger-codegen to take into account these extensions to generate java code for our clients
Develops our own swagger-ui: to facilitate this work, we added a preprocessing step to convert our swagger schema with our extensions to a valid json schema. It's easier to find a module to represent json schemas than swagger schemas in javascript. By cons we gave up the idea to test the API with the 'try it' button.

It was a year ago, maybe now ...

Refactor your APIs

Many projects don't need anyOf and oneOf, why not us ?

回答2:

In OpenAPI 3.0, you can use:

"foo": {
    "nullable": true,
    "allOf": [
        {
            "$ref": "#/definitions/Foo"
        }
    ]
}

YAML version:

foo:
  nullable: true
  allOf:
  - $ref: '#/definitions/Foo'

Wrapping $ref into allOf is needed to combine the $ref with other keywords - because $ref overwrites any sibling keywords. This is further discussed in the OpenAPI Specification repository: Reference objects don't combine well with “nullable”

来源：https://stackoverflow.com/questions/40920441/how-to-specify-a-property-can-be-null-or-a-reference-with-swagger

标签

swagger

swagger-2.0