flask-restful-swagger

We have a new project lead!

We have a new project lead, @niall-byrne (Dec 2015), thank you Niall!

What is flask-restful-swagger?

flask-restful-swagger is a wrapper for flask-restful which enables swagger support.

In essense, you just need to wrap the Api instance and add a few python decorators to get full swagger support.

How to:

Install:

pip install flask-restful-swagger

(This installs flask-restful as well)

And in your program, where you'd usually just use flask-restful, add just a little bit of sauce and get a swagger spec out.

from flask import Flask
from flask_restful import Api
from flask_restful_swagger import swagger

app = Flask(__name__)

###################################
# Wrap the Api with swagger.docs. It is a thin wrapper around the Api class that adds some swagger smarts
api = swagger.docs(Api(app), apiVersion='0.1')
###################################


# You may decorate your operation with @swagger.operation
class Todo(Resource):
    "Describing elephants"
    @swagger.operation(
        notes='some really good notes',
        responseClass=ModelClass.__name__,
        nickname='upload',
        parameters=[
            {
              "name": "body",
              "description": "blueprint object that needs to be added. YAML.",
              "required": True,
              "allowMultiple": False,
              "dataType": ModelClass2.__name__,
              "paramType": "body"
            }
          ],
        responseMessages=[
            {
              "code": 201,
              "message": "Created. The URL of the created blueprint should be in the Location header"
            },
            {
              "code": 405,
              "message": "Invalid input"
            }
          ]
        )
    def get(self, todo_id):
    
# Operations not decorated with @swagger.operation do not get added to the swagger docs

class Todo(Resource):
    def options(self, todo_id):
        """
        I'm not visible in the swagger docs
        """
        pass


# Then you add_resource as you usually would

api.add_resource(TodoList, '/todos')
api.add_resource(Todo, '/todos/<string:todo_id>')

# You define models like this:
@swagger.model
class TodoItem:
  "A description ..."
  pass

# Swagger json:
    "models": {
        "TodoItemWithArgs": {
            "description": "A description...",
            "id": "TodoItem",
        },

# If you declare an __init__ method with meaningful arguments then those args could be used to deduce the swagger model fields.
@swagger.model
class TodoItemWithArgs:
  "A description ..."
  def __init__(self, arg1, arg2, arg3='123'):
    pass

# Swagger json:
    "models": {
        "TodoItemWithArgs": {
            "description": "A description...",
            "id": "TodoItem",
            "properties": {
                "arg1": {
                    "type": "string"
                },
                "arg2": {
                    "type": "string"
                },
                "arg3": {
                    "default": "123",
                    "type": "string"
                }
            },
            "required": [
                "arg1",
                "arg2"
            ]
        },


# Additionally, if the model class has a `resource_fields` class member then flask-restful-swagger is able to deduce the swagger spec by this list of fields.

@swagger.model
class TodoItemWithResourceFields:
  resource_fields = {
      'a_string': fields.String
  }

# Swagger json:
    "models": {
        "TodoItemWithResourceFields": {
            "id": "TodoItemWithResourceFields",
            "properties": {
                "a_string": {
                    "type": "string"
                },
            }
        }

# And in order to close the loop with flask-restify you'd also need to tell flask-restify to @marshal_with the same list of fields when defining your methods.
# Example:

@marshal_with(TodoItemWithResourceFields.resource_fields)
def get()
  return ...

Using @marshal_with

Let us recap usage of @marshal_with. flask-restful has a decorator @marshal_with. With the following setup it's possible to define the swagger model types with the same logic as @marshal_with.

You have to:

# Define your model with resource_fields
@swagger.model
class TodoItemWithResourceFields:
  resource_fields = {
      'a_string': fields.String,
      'a_second_string': fields.String(attribute='a_second_string_field_name')
  }

# And use @marshal_with(YourClass.resource_fields):
@marshal_with(TodoItemWithResourceFields.resource_fields)
def get()
  return ...

Running and testing

Now run your flask app

python example.py

And visit:

curl http://localhost:5000/api/spec.json

Passing more metadata to swagger

When creating the swagger.docs object you may pass additional arguments, such as the following:

api_spec_url - where to serve the swagger spec from. Default is /api/spec. This will make the json
available at /api/spec as well as /api/spec.json and will also present a nice interactive
HTML interface at /api/spec.html

apiVersion - passed directly to swagger as the apiVersion attribute. Default: 0.0

basePath - passed directly to swagger as the basePath attribute. Default: 'http://localhost:5000' (do not include a slash at the end)

resourcePath - same as before. default: '/'

produces - same as before, passed directly to swagger. The default is ["application/json"]

swaggerVersion - passed directly to swagger. Default: 1.2

description - description of this API endpoint. Defaults to 'Auto generated API docs by flask-restful-swagger'

Accessing the result json spec and an Interactive HTML interface

Assuming you provided swagger.docs with a parameter api_spec_url='/api/spec' (or left out in which case the default is '/api/spec') you may access the resulting json at /api/spec.json. You may also access /api/spec.html where you'd find an interactive HTML page that lets you play with the API to some extent.

Here's how this HTML page would look like:

Accessing individual endpoints (.help.json)

flask-restful-swagger adds some useful help pages (well, json documents) to each of your resources. This isn't part of the swagger spec, but could be useful anyhow. With each endpoint you register, there's also an automatically registered help endpoint which ends with a .help.json extension. So for example when registering the resource api.add_resource(TodoList, '/todos') you may access the actual api through the url /todos and you may also access the help page at /todos.help.json. This help page spits out the relevant json content only for this endpoint (as opposed to /api/spec.json which spits out the entire swagger document, which could be daunting)

Example:

### python:

> api.add_resource(TodoList, '/todos')

### Shell:

$ curl localhost:5000/todos.help.json
{
    "description": null,
    "operations": [
        {
            "method": "GET",
            "nickname": "nickname",
            "parameters": [],
            "summary": null
        },
        {
            "method": "POST",
            "nickname": "create",
            "notes": "Creates a new TODO item",
            "parameters": [
                {
                    "allowMultiple": false,
                    "dataType": "TodoItem",
                    "description": "A TODO item",
                    "name": "body",
                    "paramType": "body",
                    "required": true
                }
            ],
            "responseClass": "TodoItem",
            "responseMessages": [
                {
                    "code": 201,
                    "message": "Created. The URL of the created blueprint should be in the Location header"
                },
                {
                    "code": 405,
                    "message": "Invalid input"
                }
            ],
            "summary": null
        }
    ],
    "path": "/todos"
}

When registering an endpoint with path parameters (e.g. /todos/<string:id>) then the .help url is may be found at the swagger path, e.g. /todos/{id}.help.json where {id} is just that - a literal string "{id}"