Flask-First 0.10.6

Flask extension for using "specification first" principle via OpenAPI specification.

Flask-First

Flask extension for using "specification first" principle.

Features:

• Application Factory supported.
• Validating and serializing path parameters from request.view_args to request.first_view_args.
• Validating and serializing arguments from request.args to request.first_args.
• Validating JSON from request.
• Validating JSON from response.
• Provides a Swagger UI.

---

Limitations

• Full specification in one file.

Installing

Install and update using pip:

$ pip install flask_first

Simple example

OpenAPI 3 specification file openapi.yaml:

openapi: 3.0.3
info:
  title: Simple API for Flask-First
  version: 1.0.0
paths:
  /{name}:
    parameters:
      - name: name
        in: path
        required: true
        schema:
          type: string
    get:
      operationId: index
      summary: Returns a list of items
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                type: object
                properties:
                  message:
                    type: string

File with application initialization main.py:

import os

from flask import Flask
from flask_first import First

basedir = os.path.abspath(os.path.dirname(__file__))
path_to_spec = os.path.join(basedir, 'openapi.yaml')

app = Flask(__name__)
app.config['FIRST_RESPONSE_VALIDATION'] = True
first = First(path_to_spec, app=app, swagger_ui_path='/docs')

def index(name):
    return {'message': name}

first.add_view_func(index)

if __name__ == '__main__':
    app.run()

Run application:

$ python main.py

Check url in browser http://127.0.0.1:5000/username. Check SwaggerUI url in browser http://127.0.0.1:5000/docs.

Settings

FIRST_RESPONSE_VALIDATION - Default: False. Enabling response body validation. Useful when developing. May be disabled in a production environment.

CORS support

Your need enable CORS in Flask and adding OPTIONS method in your specification. Example:

...
paths:
  /index:
    post: ...
    get: ...
    put: ...
    patch: ...
    delete: ...
    options:
      summary: CORS support
      responses:
        200:
          headers:
            Access-Control-Allow-Origin:
              schema:
                type: string
            Access-Control-Allow-Methods:
              schema:
                type: string
            Access-Control-Allow-Headers:
              schema:
                type: string
          content: { }

Additional documentation

• OpenAPI Documentation.
• OpenAPI on GitHub.
• JSON Schema Documentation.