Typical usage

from pprint import pprint

from flask_restful import Api, Resource
from flask import Flask
from apispec import APISpec
from apispec_flask_restful import RestfulPlugin

class HelloResource(Resource):
    def get(self, hello_id):
        '''A greeting endpoint.
               ---
               description: get a greeting
               responses:
                   200:
                       description: a pet to be returned
                       schema:
                           $ref: #/definitions/Pet
        '''
        pass

app = Flask(__name__)
api = Api(app)
spec = APISpec(title='Spec', version='1.0', openapi_version='3.0.2', plugins=[RestfulPlugin()])

api.add_resource(HelloResource, '/hello')

spec.path(resource=HelloResource, api=api)
pprint(spec.to_dict()['paths'])

# OrderedDict([('/hello',
#          {'get': {'description': 'get a greeting',
#                   'responses': {200: {'description': 'a pet to be returned',
#                                       'schema': {'$ref': None}}}}})])

Without API

Method path can be invoked with a resource path in a path parameter instead of api parameter:

spec.path(resource=HelloResource, path='/hello')

With Blueprint

Flask blueprints are supported too by passing Flask app in app parameter:

spec.path(resource=HelloResource, api=api, app=app)