tessl/pypi-tortoise-orm
Easy async ORM for Python, built with relations in mind
signals.mddocs/
Signals and Event Handling
Model lifecycle event system that allows registering custom handlers for model save and delete operations. Signals provide hooks to execute custom logic before or after these operations.
Capabilities
Signal Decorators
Decorators for registering signal handlers on model lifecycle events.
from tortoise.signals import pre_save, post_save, pre_delete, post_delete
@pre_save(*senders):
"""
Register models pre_save signal handler.
Args:
*senders: Model classes to listen for
Returns:
Function decorator for signal handler
"""
@post_save(*senders):
"""
Register models post_save signal handler.
Args:
*senders: Model classes to listen for
Returns:
Function decorator for signal handler
"""
@pre_delete(*senders):
"""
Register models pre_delete signal handler.
Args:
*senders: Model classes to listen for
Returns:
Function decorator for signal handler
"""
@post_delete(*senders):
"""
Register models post_delete signal handler.
Args:
*senders: Model classes to listen for
Returns:
Function decorator for signal handler
"""Signal Types
from tortoise.signals import Signals
class Signals(Enum):
"""Enumeration of available signal types."""
pre_save = "pre_save"
post_save = "post_save"
pre_delete = "pre_delete"
post_delete = "post_delete"Usage Examples
Basic Signal Handler
from tortoise.signals import pre_save, post_save
from myapp.models import User
@pre_save(User)
async def user_pre_save(sender, instance, **kwargs):
"""Called before user is saved."""
print(f"About to save user: {instance.name}")
@post_save(User)
async def user_post_save(sender, instance, created, **kwargs):
"""Called after user is saved."""
if created:
print(f"Created new user: {instance.name}")
else:
print(f"Updated user: {instance.name}")Multiple Model Handler
from tortoise.signals import post_delete
from myapp.models import User, Profile
@post_delete(User, Profile)
async def cleanup_after_delete(sender, instance, **kwargs):
"""Called after user or profile deletion."""
print(f"Deleted {sender.__name__}: {instance}")Signal Handler Parameters
Signal handlers receive the following parameters:
- sender: The model class that triggered the signal
- instance: The model instance being saved/deleted
- created: (post_save only) Boolean indicating if instance was created
- kwargs: Additional keyword arguments
Signal Execution
- pre_save: Called before
save()method execution - post_save: Called after successful
save()method execution - pre_delete: Called before
delete()method execution - post_delete: Called after successful
delete()method execution
Signals are executed synchronously during the model operation and can affect the operation's outcome if they raise exceptions.
Install with Tessl CLI
npx tessl i tessl/pypi-tortoise-orm