django-bulk-hooks 0.1.112

Hook-style hooks for Django bulk operations like bulk_create and bulk_update.

django-bulk-hooks

⚡ Bulk hooks for Django bulk operations and individual model lifecycle events.

django-bulk-hooks brings a declarative, hook-like experience to Django's bulk_create, bulk_update, and bulk_delete — including support for BEFORE_ and AFTER_ hooks, conditions, batching, and transactional safety. It also provides comprehensive lifecycle hooks for individual model operations.

✨ Features

• Declarative hook system: @hook(AFTER_UPDATE, condition=...)
• BEFORE/AFTER hooks for create, update, delete
• Hook-aware manager that wraps Django's bulk_ operations
• NEW: HookModelMixin for individual model lifecycle events
• Hook chaining, hook deduplication, and atomicity
• Class-based hook handlers with DI support
• Support for both bulk and individual model operations

🚀 Quickstart

pip install django-bulk-hooks

Define Your Model

from django.db import models
from django_bulk_hooks.models import HookModelMixin

class Account(HookModelMixin):
    balance = models.DecimalField(max_digits=10, decimal_places=2)
    # The HookModelMixin automatically provides BulkManager

Create a Hook Handler

from django_bulk_hooks import hook, AFTER_UPDATE, Hook
from django_bulk_hooks.conditions import WhenFieldHasChanged
from .models import Account

class AccountHooks(Hook):
    @hook(AFTER_UPDATE, model=Account, condition=WhenFieldHasChanged("balance"))
    def log_balance_change(self, new_records, old_records):
        print("Accounts updated:", [a.pk for a in new_records])
    
    @hook(BEFORE_CREATE, model=Account)
    def before_create(self, new_records, old_records):
        for account in new_records:
            if account.balance < 0:
                raise ValueError("Account cannot have negative balance")
    
    @hook(AFTER_DELETE, model=Account)
    def after_delete(self, new_records, old_records):
        print("Accounts deleted:", [a.pk for a in old_records])

🛠 Supported Hook Events

• BEFORE_CREATE, AFTER_CREATE
• BEFORE_UPDATE, AFTER_UPDATE
• BEFORE_DELETE, AFTER_DELETE

🔄 Lifecycle Events

Individual Model Operations

The HookModelMixin automatically triggers hooks for individual model operations:

# These will trigger BEFORE_CREATE and AFTER_CREATE hooks
account = Account.objects.create(balance=100.00)
account.save()  # for new instances

# These will trigger BEFORE_UPDATE and AFTER_UPDATE hooks
account.balance = 200.00
account.save()  # for existing instances

# This will trigger BEFORE_DELETE and AFTER_DELETE hooks
account.delete()

Bulk Operations

Bulk operations also trigger the same hooks:

# Bulk create - triggers BEFORE_CREATE and AFTER_CREATE hooks
accounts = [
    Account(balance=100.00),
    Account(balance=200.00),
]
Account.objects.bulk_create(accounts)

# Bulk update - triggers BEFORE_UPDATE and AFTER_UPDATE hooks
for account in accounts:
    account.balance *= 1.1
Account.objects.bulk_update(accounts, ['balance'])

# Bulk delete - triggers BEFORE_DELETE and AFTER_DELETE hooks
Account.objects.bulk_delete(accounts)

Queryset Operations

Queryset operations are also supported:

# Queryset update - triggers BEFORE_UPDATE and AFTER_UPDATE hooks
Account.objects.update(balance=0.00)

# Queryset delete - triggers BEFORE_DELETE and AFTER_DELETE hooks
Account.objects.delete()

🧠 Why?

Django's bulk_ methods bypass signals and save(). This package fills that gap with:

• Hooks that behave consistently across creates/updates/deletes
• NEW: Individual model lifecycle hooks that work with save() and delete()
• Scalable performance via chunking (default 200)
• Support for @hook decorators and centralized hook classes
• NEW: Automatic hook triggering for admin operations and other Django features
• NEW: Proper ordering guarantees for old/new record pairing in hooks (Salesforce-like behavior)

📦 Usage Examples

Individual Model Operations

# These automatically trigger hooks
account = Account.objects.create(balance=100.00)
account.balance = 200.00
account.save()
account.delete()

Bulk Operations

# These also trigger hooks
Account.objects.bulk_create(accounts)
Account.objects.bulk_update(accounts, ['balance'])
Account.objects.bulk_delete(accounts)

Advanced Hook Usage

class AdvancedAccountHooks(Hook):
    @hook(BEFORE_UPDATE, model=Account, condition=WhenFieldHasChanged("balance"))
    def validate_balance_change(self, new_records, old_records):
        for new_account, old_account in zip(new_records, old_records):
            if new_account.balance < 0 and old_account.balance >= 0:
                raise ValueError("Cannot set negative balance")
    
    @hook(AFTER_CREATE, model=Account)
    def send_welcome_email(self, new_records, old_records):
        for account in new_records:
            # Send welcome email logic here
            pass

Salesforce-like Ordering Guarantees

The system ensures that old_records and new_records are always properly paired, regardless of the order in which you pass objects to bulk operations:

class LoanAccountHooks(Hook):
    @hook(BEFORE_UPDATE, model=LoanAccount)
    def validate_account_number(self, new_records, old_records):
        # old_records[i] always corresponds to new_records[i]
        for new_account, old_account in zip(new_records, old_records):
            if old_account.account_number != new_account.account_number:
                raise ValidationError("Account number cannot be changed")

# This works correctly even with reordered objects:
accounts = [account1, account2, account3]  # IDs: 1, 2, 3
reordered = [account3, account1, account2]  # IDs: 3, 1, 2

# The hook will still receive properly paired old/new records
LoanAccount.objects.bulk_update(reordered, ['balance'])

🧩 Integration with Queryable Properties

You can extend from BulkManager to support formula fields or property querying.

class MyManager(BulkManager, QueryablePropertiesManager):
    pass

📝 License

MIT © 2024 Augend / Konrad Beck