Request Hooks in Python
From the Flask cheat sheet · Middleware & Hooks · verified Jul 2026
Request Hooks
Execute code before and after requests
python
# Quick Reference
@app.before_request
def before():
g.start_time = time.time()
@app.after_request
def after(response):
response.headers['X-Time'] = time.time() - g.start_time
return response💡 Use g object to store request-scoped data
🔍 before_request can return early to abort request
⚡ after_request modifies all responses
📌 teardown runs even if exception occurs
middlewarehooks