django-lifecycle

import os from django.db import models from django_lifecycle import LifecycleModelMixin, hook, BEFORE_SAVE, AFTER_UPDATE, POST_INIT from django_lifecycle.conditions import is_greater_than, is_less_than # NOTE: This example assumes Django settings are configured, e.g., via manage.py shell # or a test environment. class Product(LifecycleModelMixin, models.Model): name = models.CharField(max_length=255) price = models.DecimalField(max_digits=10, decimal_places=2, default=0) stock = models.IntegerField(default=0) sku = models.CharField(max_length=100, unique=True, blank=True, null=True) @hook(POST_INIT) def on_init(self): if not self.sku: self.sku = f"SKU-{os.urandom(4).hex().upper()}" @hook(BEFORE_SAVE) def ensure_name_capitalized(self): self.name = self.name.capitalize() @hook(AFTER_UPDATE, when='price', has_changed=True) def log_price_change(self): print(f"Product '{self.name}' (SKU: {self.sku}) price changed from {self.initial_value('price')} to {self.price}") @hook(BEFORE_SAVE, when='stock', is_greater_than=0, is_less_than=10) def notify_low_stock(self): print(f"WARNING: Stock for '{self.name}' (SKU: {self.sku}) is critically low ({self.stock})!") def __str__(self): return self.name # Example Usage (run in a Django shell or similar): # from your_app.models import Product # Replace 'your_app' # # p1 = Product.objects.create(name="keyboard", price=75.00, stock=20) # print(f"Created: {p1.name} with SKU: {p1.sku}") # SKU will be auto-generated on POST_INIT # # p1.price = 80.50 # p1.save() # Triggers log_price_change # # p1.stock = 5 # p1.save() # Triggers notify_low_stock # # p2 = Product(name="mouse", price=25.00, stock=15) # p2.save() # Triggers ensure_name_capitalized and on_init (for sku) # print(f"Created: {p2.name} with SKU: {p2.sku}")