Special Topics

Solutions to specific problems are documented here.

Adding Additional Fields To Schema Objects

To add additional fields (e.g. "discriminator") to Schema objects generated from spec.components.schema , pass them to the component parameter. If your’e using MarshmallowPlugin, the component properties will get merged with the autogenerated properties.

properties = {
    "id": {"type": "integer", "format": "int64"},
    "name": {"type": "string", "example": "doggie"},
}

spec.components.schema("Pet", component={"discriminator": "petType"}, schema=PetSchema)

Note

Be careful about the input that you pass to component. apispec will not guarantee that the passed fields are valid against the OpenAPI spec.

Rendering to YAML or JSON

YAML

spec.to_yaml()

Note

to_yaml requires PyYAML to be installed. You can install apispec with YAML support using:

pip install 'apispec[yaml]'

JSON

import json

json.dumps(spec.to_dict())

Documenting Top-level Components

The APISpec object contains helpers to add top-level components:

Component type	Helper method	OpenAPI version
Schema (f.k.a. “definition” in OAS v2)	spec.components.schema	2, 3
Parameter	spec.components.parameter	2, 3
Reponse	spec.components.response	2, 3
Header	spec.components.response	3
Example	spec.components.response	3

To add other top-level objects, pass them to the APISpec as keyword arguments.

Here is an example that includes a Server Object.

import yaml
from apispec import APISpec
from apispec.ext.marshmallow import MarshmallowPlugin
from apispec.utils import validate_spec

OPENAPI_SPEC = """
openapi: 3.0.2
info:
  description: Server API document
  title: Server API
  version: 1.0.0
servers:
- url: http://localhost:{port}/
  description: The development API server
  variables:
    port:
      enum:
      - '3000'
      - '8888'
      default: '3000'
"""

settings = yaml.safe_load(OPENAPI_SPEC)
# retrieve  title, version, and openapi version
title = settings["info"].pop("title")
spec_version = settings["info"].pop("version")
openapi_version = settings.pop("openapi")

spec = APISpec(
    title=title,
    version=spec_version,
    openapi_version=openapi_version,
    plugins=(MarshmallowPlugin(),),
    **settings
)

validate_spec(spec)

When adding components, the main advantage of using dedicated methods over passing them as kwargs is the ability to use plugin helpers. For instance, MarshmallowPlugin has helpers to resolve schemas in parameters and responses.

Documenting Security Schemes

Use spec.components.security_scheme to document Security Scheme Objects.

from pprint import pprint
from apispec import APISpec

spec = APISpec(title="Swagger Petstore", version="1.0.0", openapi_version="3.0.2")

api_key_scheme = {"type": "apiKey", "in": "header", "name": "X-API-Key"}
jwt_scheme = {"type": "http", "scheme": "bearer", "bearerFormat": "JWT"}

spec.components.security_scheme("api_key", api_key_scheme)
spec.components.security_scheme("jwt", jwt_scheme)

pprint(spec.to_dict()["components"]["securitySchemes"], indent=2)
# { 'api_key': {'in': 'header', 'name': 'X-API-Key', 'type': 'apiKey'},
#   'jwt': {'bearerFormat': 'JWT', 'scheme': 'bearer', 'type': 'http'}}

Referencing Top-level Components

On OpenAPI, top-level component are meant to be referenced using a $ref, as in {$ref: '#/components/schemas/Pet'} (OpenAPI v3) or {$ref: '#/definitions/Pet'} (OpenAPI v2).

APISpec automatically resolves references in paths and in components themselves when a string is provided while a dict is expected. Passing a fully-resolved reference is not supported. In other words, rather than passing {"schema": {$ref: '#/components/schemas/Pet'}}, the user must pass {"schema": "Pet"}. APISpec assumes a schema reference named "Pet" has been defined and builds the reference using the components location corresponding to the OpenAPI version.