OpenAPI 3 Generator

The goal of this project is to create a generator that conveniently creates API definitions in the OpenAPI 3 format using marshmallow classes and saves them into a YAML file.

You can think this project as programmable API definitions/documentation for your API (your API can be written in any language, not only in Python).

Python is used here just for convenience of describing classes and has less code yet strong typing.

Then you can inject the generated YAML file with Swagger UI to any project (just a page that renders Swagger UI HTML code which requests the generated YAML file).

Why I made the project

I was developing a project in PHP using this library php-swagger. It has ability to describe an API using annotations in docstrings of classes/methods (you can find alternative projects for your programming language, the idea behind is to describe API's definitions something near the code: routes, paths, views, etc).

But this method has some problems to me:

I couldn't describe the API's definitions as real code when the interpreter/compiler could fix my issues with schemas/paths
I had issues with spaces in docstrings and it looked ugly and messy
I wanted to have versioned pages of my API (i.e.: v1.0, v1.1, v1.2)
I wanted to make validation of the resulted API definitions after writing it

What does the project do?

Generates a YAML file of your API with paths, schemes, requests, security methods in the OpenAPI 3 format
Runs a Flask web server for prototyping (Flask is used only for development purposes, it is not meant here to create an API using Flask, but you can do it as well)

Structure of the project

config.py : basic information about the API (title, description, support contacts, servers, tags info and etc)
swagger_ui.py : a Flask web server for prototyping
build.py : a build script to create the api.yaml file
api/paths : your API paths
api/requests : your API requests
api/schemas : your API schemas for responses and request bodies
api/project.py : here you add your classes of schemas, requests and paths

Requirements

Tools:

Python 3.7
pipenv

Knowledge in:

Swagger
Python
YAML format

How to use?

Just fork or copy this project to your computer using git:

git clone https://github.com/egorsmkv/openapi3-generator.git
cd openapi3-generator

After the cloning, initialize the environment:

# install all dependencies
pipenv install

# enter the environment
pipenv shell

One-time mode

To create an api.yaml file with your API definitions in the OpenAPI 3 format:

# create an api.yaml file
python build.py

Prototyping mode

If you are prototyping your API then you can run a Flask web server with pre-defined Swagger UI using GNU make and start to create your API by editing schemas, paths and other objects.

The web server is running in debug mode, it will reload the app each time when you change something in the project and after any change you can just refresh a page to see new version your API definitions in Swagger UI.

make run

# * Running on http://127.0.0.1:8060/ (Press CTRL+C to quit)
# * Restarting with stat
# * Debugger is active!

If you don't have GNU make, use the following commands:

export FLASK_APP="swagger_ui.py"
export FLASK_ENV="development"

python -m flask run --port=8060

You can find the Swagger UI page on http://127.0.0.1:8060 in your browser.

egorsmkv / openapi3-generator