flask-typed-routes 0.2.0

Flask extension designed to effortlessly validate requests with Pydantic based on standard Python type hints.

About

flask_typed_routes is a Flask extension designed to effortlessly validate requests with Pydantic based on standard Python type hints.

Documentation: https://rmoralespp.github.io/flask_typed_routes/

Features

• 🎯 Type Safety: Automatically validates requests using Python type hints.
• 🔌 Easy Integration: Simple extension for validating Flask routes.
• ⚠️ Error Handling: Clear and automatic responses for validation failures.
• ✨ Autocomplete: Editor integration with comprehensive suggestions.
• ⚙️ Validation Modes: Supports automatic validation for all routes and manual validation for specific routes using decorators.
• 📖 OpenAPI Support: Automatically generates an OpenAPI schema, ensuring clear documentation and seamless integration with OpenAPI tools.

Requirements

• Python 3.10+
• Pydantic 2.0+
• Flask

Installation

To install flask_typed_routes using pip, run the following command:

pip install flask_typed_routes

Getting Started

This tool offers comprehensive validation for various types of request parameters, including Path, Query, Body, Header, and Cookie parameters.

Example of a simple Flask application using flask_typed_routes:

Create a file items.py with:

import typing as t

import annotated_types as at
import flask
import flask_typed_routes as ftr
import pydantic

app = flask.Flask(__name__)
ftr.FlaskTypedRoutes(app)

Skip = pydantic.NonNegativeInt # custom Pydantic type
Limit = t.Annotated[int, at.Ge(1), at.Le(100)] # custom Annotated type

@app.get('/items/<user>/')
def read_items(user: str, skip: Skip = 0, limit: Limit = 10):
    # Parameters not included in the "path" are automatically treated as "query" parameters.
    data = {
        'user': user,
        'skip': skip,
        'limit': limit,
    }
    return flask.jsonify(data)

Run the server with:

flask --app items run --debug

Open your browser and go to http://127.0.0.1:5000/items/myuser/?skip=20 You will see the JSON response as:

{
  "limit": 10,
  "skip": 20,
  "user": "myuser"
}

Validation: Open your browser and go to http://127.0.0.1:5000/items/myuser/?skip=abc You will see the JSON response with the error details because the skip parameter is not an integer:

{
  "errors": [
    {
      "input": "abc",
      "loc": [
        "query",
        "skip"
      ],
      "msg": "Input should be a valid integer, unable to parse string as an integer",
      "type": "int_parsing",
      "url": "https://errors.pydantic.dev/2.9/v/int_parsing"
    }
  ]
}

Example with Pydantic Models

You can also use Pydantic models to validate request data in Flask routes. Now let's update the items.py file with:

import pydantic
import flask
import flask_typed_routes as ftr

app = flask.Flask(__name__)
ftr.FlaskTypedRoutes(app)


class Item(pydantic.BaseModel):
    name: str
    description: str = None
    price: float


@app.post('/items/')
def create_item(item: Item):
    return flask.jsonify(item.model_dump())


@app.put('/items/<item_id>/')
def update_item(item_id: int, item: Item):
    return flask.jsonify({'item_id': item_id, **item.model_dump()})

Using Flask Blueprints

You can also use flask_typed_routes with Flask Blueprints.

Now let's update the items.py file with:

import flask
import flask_typed_routes as ftr

app = flask.Flask(__name__)
ftr.FlaskTypedRoutes(app)
blp = flask.Blueprint('items', __name__, url_prefix='/v2')


@blp.get('/items/')
def read_items(skip: int = 0, limit: int = 10, country: str = 'US'):
    data = {'skip': skip, 'limit': limit, 'country': country}
    return flask.jsonify(data)


app.register_blueprint(blp)

Using Flask Class-Based Views

You can also use flask_typed_routes with Flask Class-Based Views.

Now let's update the items.py file with:

import flask
import flask.views
import flask_typed_routes as ftr

app = flask.Flask(__name__)
ftr.FlaskTypedRoutes(app)


class UserProducts(flask.views.View):

    def dispatch_request(self, user: str, skip: int = 0, limit: int = 10):
        data = {'user': user, 'skip': skip, 'limit': limit}
        return flask.jsonify(data)


class UserOrders(flask.views.MethodView):

    def get(self, user: str, skip: int = 0, limit: int = 10):
        data = {'user': user, 'skip': skip, 'limit': limit}
        return flask.jsonify(data)


app.add_url_rule('/products/<user>/', view_func=UserProducts.as_view('user_products'))
app.add_url_rule('/orders/<user>/', view_func=UserOrders.as_view('user_orders'))

Interactive API docs

You can OpenApi schema generated by flask_typed_routes with any OpenApi tools to generate interactive API docs for your Flask application. In this example we will use the swagger-ui-py library.

pip install swagger-ui-py  # ignore if already installed

import flask
import pydantic
import swagger_ui

import flask_typed_routes as ftr

app = flask.Flask(__name__)
app_ftr = ftr.FlaskTypedRoutes(app)
swagger_ui.api_doc(app, config_rel_url=app_ftr.openapi_url_json, url_prefix=app_ftr.openapi_url_prefix)


class Item(pydantic.BaseModel):
    name: str
    description: str = None
    price: float


@app.get('/items/<user>/')
def read_items(user: str, skip: int = 0, limit: int = 10):
    data = {'user': user, 'skip': skip, 'limit': limit}
    return flask.jsonify(data)


@app.post('/items/')
def create_item(item: Item):
    return flask.jsonify(item.model_dump())


@app.put('/items/<item_id>/')
def update_item(item_id: int, item: Item):
    return flask.jsonify({'item_id': item_id, **item.model_dump()})


@app.delete('/items/<item_id>/')
def remove_item(item_id: int):
    return flask.jsonify({'item_id': item_id})

Open your browser and go to http://127.0.0.1:5000/docs/

Create item endpoint:

Read Items endpoint:

Documentation

For more detailed information and usage examples, refer to the project documentation

Development

To contribute to the project, you can run the following commands for testing and documentation:

Running Unit Tests

Install the development dependencies and run the tests:

(env)$ pip install -r requirements-dev.txt  # Skip if already installed
(env)$ python -m pytest tests/
(env)$ python -m pytest --cov # Run tests with coverage

Building the Documentation

To build the documentation locally, use the following commands:

(env)$ pip install -r requirements-doc.txt # Skip if already installed
(env)$ mkdocs serve # Start live-reloading docs server
(env)$ mkdocs build # Build the documentation site

License

This project is licensed under the MIT license.