Hackforge Academy

Explanation

Flask hooks allow code to run at specific stages of the request lifecycle.

Code:

Request
  ↓
before_request
  ↓
Route Function
  ↓
after_request
  ↓
Response

Explanation

before_request runs before the matched route function and can be used for authentication or request preparation.

Code:

@app.before_request
def before_request():
    print('Request started')

Explanation

after_request runs after the route function and can modify the response before it is returned.

Code:

@app.after_request
def after_request(response):
    response.headers['X-App'] = 'Flask'
    return response

Explanation

teardown_request runs when request processing is complete and is useful for cleanup operations.

Code:

@app.teardown_request
def teardown_request(exception):
    print('Request completed')

Explanation

The complete Flask request lifecycle passes through request creation, hooks, routing, view execution, response processing, and teardown.

Code:

HTTP Request
     ↓
before_request
     ↓
Routing
     ↓
View Function
     ↓
after_request
     ↓
HTTP Response
     ↓
teardown_request