Events¶
Websauna uses Pyramid’s event mechanism to decouple logic between Python modules.
Firing events¶
For each event kind, a new event class is created holding data related to the event. Create events.py in your application and place different events your application can fire there.
Example event:
"""Events fired by websauna.system.user package."""
from websauna.system.http import Request
from websauna.system.user.models import User
class FirstLogin:
"""User logs in to the site for the first time.
Fired upon
* Social media login
* After clicking email activation link
"""
def __init__(self, request:Request, user:User):
self.request = request
self.user = user
Then you can fire the event using pyramid.registry.Registry.notify():
if not user.last_login_at:
e = events.FirstLogin(request, user)
request.registry.notify(e)
Subscribing events¶
Create subscribers.py in your application and place event handlers there.
Here is an example event subscriber:
"""Handle incoming user events."""
from pyramid.events import subscriber
from websauna.system.user.events import UserAuthSensitiveOperation
from websauna.utils.time import now
@subscriber(UserAuthSensitiveOperation)
def user_auth_details_changes(event:UserAuthSensitiveOperation):
"""Default logic how to invalidate sessions on user auth detail changes.
If you are using different session management model you can install a custom handle.
:param event: Incoming event instance
"""
user = event.user
# Update the timestamp which session validation checks on every request
user.last_auth_sensitive_operation_at = now()
You need to install your event handles by scanning your subscribers module in your app Initializer:
# Grab incoming auth details changed events
from myapp import subscribers
self.config.scan(subscribers)