Learning Objectives

• Implement rate limiting
• Add SQL injection protection
• Optimize frontend bundle

python
Run Inline
from flask_limiter import Limiter
from flask_limiter.util import get_remote_address
limiter = Limiter(app, key_func=get_remote_address)
@app.route('/api/login')
@limiter.limit("5 per minute")
def login():
    # Rate limited to prevent brute force
    pass

• Code splitting with React.lazy
• Image optimization (WebP, lazy loading)
• Bundle analysis with webpack-bundle-analyzer
• Caching with service workers

Q1: How to prevent SQL injection?

Use ORM (SQLAlchemy) which parameterizes queries. Never use f-strings/format for raw SQL with user input. Q2: What is CORS and how to configure it?

CORS = Cross-Origin Resource Sharing. Configure allowed origins in Flask-CORS. Restrict to specific domains in production. Q3: How to handle file upload security?

Validate file type (magic bytes), limit file size, scan for malware, store in dedicated cloud storage (S3), never in application directory. Join Discord PreviousMilestone 6: Testing & CI/CD PipelineNextMilestone 8: Final Integration & Documentation