Flask API Development
Table of Contents
Overview
Create efficient Flask APIs with blueprints for modular organization, SQLAlchemy for ORM, JWT authentication, comprehensive error handling, and proper request validation following REST principles.
When to Use
- Building RESTful APIs with Flask
- Creating microservices with minimal overhead
- Implementing lightweight authentication systems
- Designing API endpoints with proper validation
- Integrating with relational databases
- Building request/response handling systems
Quick Start
Minimal working example:
# app.py
from flask import Flask, request, jsonify
from flask_cors import CORS
from flask_sqlalchemy import SQLAlchemy
from flask_jwt_extended import JWTManager
import os
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = os.getenv('DATABASE_URL', 'sqlite:///app.db')
app.config['JWT_SECRET_KEY'] = os.getenv('JWT_SECRET_KEY', 'dev-secret')
app.config['JSON_SORT_KEYS'] = False
db = SQLAlchemy(app)
jwt = JWTManager(app)
CORS(app)
# Request ID middleware
@app.before_request
def assign_request_id():
import uuid
request.request_id = str(uuid.uuid4())
# Error handlers
@app.errorhandler(400)
def bad_request(error):
// ... (see reference guides for full implementation)
Reference Guides
Detailed implementations in the references/ directory:
| Guide | Contents |
|---|---|
| Flask Application Setup | Flask Application Setup |
| Database Models with SQLAlchemy | Database Models with SQLAlchemy |
| Authentication and JWT | Authentication and JWT |
| Blueprints for Modular API Design | Blueprints for Modular API Design |
| Request Validation | Request Validation |
| Application Factory and Configuration | Application Factory and Configuration |
Best Practices
✅ DO
- Use blueprints for modular organization
- Implement proper authentication with JWT
- Validate all user input
- Use SQLAlchemy ORM for database operations
- Implement comprehensive error handling
- Use pagination for collection endpoints
- Log errors and important events
- Return appropriate HTTP status codes
- Implement CORS properly
- Use environment variables for configuration
❌ DON'T
- Store secrets in code
- Use global variables for shared state
- Ignore database transactions
- Trust user input without validation
- Return stack traces in production
- Use mutable default arguments
- Forget to handle database connection errors
- Implement authentication in route handlers