flask

Flask

Flask is a lightweight WSGI web framework for Python, offering modular blueprints, extensible request handling, and flexible integration with database ORMs and async handlers.

When to Use

• Lightweight Python Microservices: Rapidly prototyping APIs and small-to-medium web services without boilerplate.
• Machine Learning Inference Wrappers: Wrapping data science pipelines and Scikit-learn/XGBoost models with minimal overhead.
• Custom Architectures: Projects requiring complete freedom to select ORMs, auth libraries, and database drivers.
• Internal Scripting & Admin Utilities: Embedding web dashboards inside automated Python operations tooling.

Quick Start

from flask import Flask
import asyncio

app = Flask(__name__)

@app.route("/")
async def hello():
    await asyncio.sleep(1)
    return "Hello form Async Flask!"

Core Concepts

Application Factory & Blueprint Pattern

Structuring scalable Flask applications:

# app/__init__.py
from flask import Flask
from .routes.users import user_bp
from .routes.orders import order_bp

def create_app(config_object="app.config.ProductionConfig"):
    app = Flask(__name__)
    app.config.from_object(config_object)

    # Register modular blueprints
    app.register_blueprint(user_bp, url_prefix="/api/v1/users")
    app.register_blueprint(order_bp, url_prefix="/api/v1/orders")

    return app

Type-Safe Request Handling & JSON Responses

Parsing payloads and handling route parameters:

# app/routes/users.py
from flask import Blueprint, request, jsonify, abort

user_bp = Blueprint("users", __name__)

@user_bp.route("/<int:user_id>", methods=["GET"])
def get_user(user_id):
    if user_id <= 0:
        abort(404, description="User not found")
    return jsonify({
        "id": user_id,
        "name": f"User_{user_id}",
        "status": "active"
    }), 200

@user_bp.route("/", methods=["POST"])
def create_user():
    data = request.get_json()
    if not data or "email" not in data:
        return jsonify({"error": "Email is required"}), 400

    return jsonify({"id": 42, "email": data["email"]}), 201