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Adds title, description, type, domain, and tags frontmatter to every doc for improved KB semantic search. The description field is prepended to every search chunk, and domain/type/tags enable filtered queries. Type values: context, guide, runbook, reference, troubleshooting Domain values match directory structure (networking, docker, etc.) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
104 lines
2.9 KiB
Markdown
104 lines
2.9 KiB
Markdown
---
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title: "Python Web Framework Examples"
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description: "Code examples for Flask and FastAPI web applications including API structure, async patterns, SQLAlchemy integration, and configuration management with dataclasses."
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type: reference
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domain: development
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tags: [python, flask, fastapi, sqlalchemy, web-api, async]
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---
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# Python Web Framework Examples
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## Flask API Structure
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```python
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# app.py
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from flask import Flask, jsonify, request
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from flask_sqlalchemy import SQLAlchemy
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import logging
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app = Flask(__name__)
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app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///app.db'
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db = SQLAlchemy(app)
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# Configure logging
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logging.basicConfig(level=logging.INFO)
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logger = logging.getLogger(__name__)
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class User(db.Model):
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id = db.Column(db.Integer, primary_key=True)
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username = db.Column(db.String(80), unique=True, nullable=False)
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email = db.Column(db.String(120), unique=True, nullable=False)
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@app.route('/api/users', methods=['GET'])
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def get_users():
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try:
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users = User.query.all()
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return jsonify([{'id': u.id, 'username': u.username, 'email': u.email} for u in users])
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except Exception as e:
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logger.error(f"Error fetching users: {e}")
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return jsonify({'error': 'Internal server error'}), 500
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@app.route('/api/users', methods=['POST'])
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def create_user():
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try:
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data = request.get_json()
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user = User(username=data['username'], email=data['email'])
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db.session.add(user)
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db.session.commit()
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return jsonify({'id': user.id}), 201
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except Exception as e:
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logger.error(f"Error creating user: {e}")
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return jsonify({'error': 'Bad request'}), 400
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if __name__ == '__main__':
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with app.app_context():
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db.create_all()
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app.run(debug=True)
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```
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## FastAPI Async Pattern
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```python
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# main.py
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from fastapi import FastAPI, HTTPException, Depends
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from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
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from sqlalchemy.orm import sessionmaker
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import logging
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app = FastAPI()
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# Database setup
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DATABASE_URL = "sqlite+aiosqlite:///./app.db"
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engine = create_async_engine(DATABASE_URL)
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AsyncSessionLocal = sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
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async def get_db():
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async with AsyncSessionLocal() as session:
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yield session
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@app.get("/api/users")
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async def get_users(db: AsyncSession = Depends(get_db)):
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try:
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# Database query logic here
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return {"users": []}
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except Exception as e:
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logging.error(f"Error: {e}")
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raise HTTPException(status_code=500, detail="Internal server error")
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```
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## Configuration Management
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```python
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# config.py
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import os
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from dataclasses import dataclass
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@dataclass
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class Config:
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SECRET_KEY: str = os.getenv('SECRET_KEY', 'dev-secret-key')
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DATABASE_URL: str = os.getenv('DATABASE_URL', 'sqlite:///app.db')
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DEBUG: bool = os.getenv('DEBUG', 'False').lower() == 'true'
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LOG_LEVEL: str = os.getenv('LOG_LEVEL', 'INFO')
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config = Config()
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``` |