Generate REST API and OpenAPI documentation for your Flask project.

Flask OpenAPI3 is a web API framework based on Flask. It uses Pydantic to verify data and automatic generation of interaction documentation.

The key features are:

• Easy to code: Easy to use and easy to learn

• Standard document specification: Based on OpenAPI Specification

• Interactive OpenAPI documentation: Swagger, Redoc, RapiDoc, RapiPdf, Scalar, Elements

• Data validation: Fast data verification based on Pydantic

Requirements

Python 3.8+

flask-openapi3 is dependent on the following libraries:

• Flask for the web app.
• Pydantic for the data validation.

Installation

pip install -U flask-openapi3[swagger]

or

conda install -c conda-forge flask-openapi3[swagger]

Optional dependencies

• python-email-validator supports email verification.
• python-dotenv enables support for Environment Variables From dotenv when running flask commands.
• pyyaml is used to output the OpenAPI document in yaml format.
• asgiref allows views to be defined with async def and use await.
• flask-openapi3-plugins Provide OpenAPI UI for flask-openapi3.

To install these dependencies with flask-openapi3:

pip install flask-openapi3[yaml]
# or
pip install flask-openapi3[async]
# or
pip install flask-openapi3[dotenv]
# or
pip install flask-openapi3[email]
# or all
pip install flask-openapi3[yaml,async,dotenv,email]
# or manually
pip install pyyaml asgiref python-dotenv email-validator
# OpenAPI UI plugins
pip install -U flask-openapi3[swagger,redoc,rapidoc,rapipdf,scalar,elements]

A Simple Example

Here's a simple example, further go to the Example.

from pydantic import BaseModel

from flask_openapi3 import Info, Tag
from flask_openapi3 import OpenAPI

info = Info(title="book API", version="1.0.0")
app = OpenAPI(__name__, info=info)

book_tag = Tag(name="book", description="Some Book")


class BookQuery(BaseModel):
    age: int
    author: str


@app.get("/book", summary="get books", tags=[book_tag])
def get_book(query: BookQuery):
    """
    to get all books
    """
    return {
        "code": 0,
        "message": "ok",
        "data": [
            {"bid": 1, "age": query.age, "author": query.author},
            {"bid": 2, "age": query.age, "author": query.author}
        ]
    }


if __name__ == "__main__":
    app.run(debug=True)

Class-based API View Example

from typing import Optional

from pydantic import BaseModel, Field

from flask_openapi3 import OpenAPI, Tag, Info, APIView


info = Info(title='book API', version='1.0.0')
app = OpenAPI(__name__, info=info)

api_view = APIView(url_prefix="/api/v1", view_tags=[Tag(name="book")])


class BookPath(BaseModel):
    id: int = Field(..., description="book ID")


class BookQuery(BaseModel):
    age: Optional[int] = Field(None, description='Age')


class BookBody(BaseModel):
    age: Optional[int] = Field(..., ge=2, le=4, description='Age')
    author: str = Field(None, min_length=2, max_length=4, description='Author')


@api_view.route("/book")
class BookListAPIView:
    a = 1

    @api_view.doc(summary="get book list")
    def get(self, query: BookQuery):
        print(self.a)
        return query.model_dump_json()

    @api_view.doc(summary="create book")
    def post(self, body: BookBody):
        """description for a created book"""
        return body.model_dump_json()


@api_view.route("/book/<id>")
class BookAPIView:
    @api_view.doc(summary="get book")
    def get(self, path: BookPath):
        print(path)
        return "get"

    @api_view.doc(summary="update book")
    def put(self, path: BookPath):
        print(path)
        return "put"

    @api_view.doc(summary="delete book", deprecated=True)
    def delete(self, path: BookPath):
        print(path)
        return "delete"


app.register_api_view(api_view)

if __name__ == "__main__":
    app.run(debug=True)

API Document

Run the simple example, and go to http://127.0.0.1:5000/openapi.

OpenAPI UI plugins are optional dependencies that require manual installation.

pip install -U flask-openapi3[swagger,redoc,rapidoc,rapipdf,scalar,elements]

More optional ui templates goto the document about UI_Templates.