Flask API Development

Table of Contents

• Overview
• When to Use
• Quick Start
• Reference Guides
• Best Practices

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