OpenAlchemy

Translates an OpenAPI schema to SQLAlchemy models.

Supports OpenAPI 3.0 and 3.1.

Installation

python -m pip install OpenAlchemy
# To be able to load YAML file
python -m pip install OpenAlchemy[yaml]

Example

For example, given the following OpenAPI specification:

# ./examples/simple/example-spec.yml
openapi: "3.0.0"

info:
  title: Test Schema
  description: API to illustrate OpenAlchemy MVP.
  version: "0.1"

paths:
  /employee:
    get:
      summary: Used to retrieve all employees.
      responses:
        200:
          description: Return all employees from the database.
          content:
            application/json:
              schema:
                type: array
                items:
                  "$ref": "#/components/schemas/Employee"

components:
  schemas:
    Employee:
      description: Person that works for a company.
      type: object
      x-tablename: employee
      properties:
        id:
          type: integer
          description: Unique identifier for the employee.
          example: 0
          x-primary-key: true
          x-autoincrement: true
        name:
          type: string
          description: The name of the employee.
          example: David Andersson
          x-index: true
        division:
          type: string
          description: The part of the company the employee works in.
          example: Engineering
          x-index: true
        salary:
          type: number
          description: The amount of money the employee is paid.
          example: 1000000.00
      required:
        - id
        - name
        - division

The SQLALchemy models file then becomes:

# models.py
from open_alchemy import init_yaml

init_yaml("./examples/simple/example-spec.yml")

The Base and Employee objects can be accessed:

from open_alchemy.models import Base
from open_alchemy.models import Employee

With the models_filename parameter a file is auto generated with type hints for the SQLAlchemy models at the specified location, for example: type hinted models example. This adds support for IDE auto complete, for example for the model initialization:

and for properties and methods available on an instance:

An extensive set of examples with a range of features is here:

examples for main features

An example API has been defined using connexion and Flask here:

example connexion app

Documentation

Read the Docs

Buy me a coffee

Features

• initializing from JSON,
• initializing from YAML,
• build a package with the models for distribution, packaged as sdist or wheel,
• automatically generate a models file,
• integer (32 and 64 bit),
• number (float only),
• boolean,
• string,
• password,
• byte,
• binary,
• date,
• date-time,
• generic JSON data,
• $ref references for columns and models,
• remote $ref to other files on the same file system (not supported on Windows),
• remote $ref to other files at a URL,
• primary keys,
• auto incrementing,
• indexes,
• composite indexes,
• unique constraints,
• composite unique constraints,
• column nullability,
• foreign keys,
• default values for columns (both application and database side),
• many to one relationships,
• one to one relationships,
• one to many relationships,
• many to many relationships,
• many to many relationships with custom association tables,
• custom foreign keys for relationships,
• back references for relationships,
• allOf inheritance for columns and models,
• joined and single table inheritance,
• from_str model methods to construct from JSON string,
• from_dict model methods to construct from dictionaries,
• to_str model methods to convert instances to JSON string,
• __str__ model methods to support the python str function,
• __repr__ model methods to support the python repr function,
• to_dict model methods to convert instances to dictionaries,
• readOnly and writeOnly for influence the conversion to and from dictionaries,
• exposing created models under open_alchemy.models removing the need for models.py files,
• ability to mix in arbitrary classes into a model,
• can use the short x- prefix or a namespaced x-open-alchemy- prefix for extension properties and
• grouping models into schemas.

Contributing

Fork and checkout the repository. To install:

poetry install

To run tests:

poetry run pytest

Make your changes and raise a pull request.

Compiling Docs

poetry shell
cd docs
make html

This creates the index.html file in docs/build/html/index.html.

Release Commands

rm -r dist/*
poetry build
poetry publish