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thrillwiki_django_no_react/history_tracking/models.py

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3.8 KiB
Python

# history_tracking/models.py
from django.db import models
from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes.fields import GenericForeignKey
from django.contrib.auth import get_user_model
from simple_history.models import HistoricalRecords
from .mixins import HistoricalChangeMixin
from typing import Any, Type, TypeVar, cast
from django.db.models import QuerySet
T = TypeVar('T', bound=models.Model)
class DiffMixin:
"""Mixin to add diffing capabilities to pghistory events"""
def get_prev_record(self):
"""Get the previous record for this instance"""
try:
return type(self).objects.filter(
pgh_created_at__lt=self.pgh_created_at,
pgh_obj_id=self.pgh_obj_id
).order_by('-pgh_created_at').first()
except (AttributeError, TypeError):
return None
def diff_against_previous(self):
"""Compare this record against the previous one"""
prev_record = self.get_prev_record()
if not prev_record:
return {}
changes = {}
skip_fields = {
'pgh_id', 'pgh_created_at', 'pgh_label',
'pgh_obj_id', 'pgh_context_id', '_state'
}
for field in self.__dict__:
if field not in skip_fields and not field.startswith('_'):
try:
old_value = getattr(prev_record, field)
new_value = getattr(self, field)
if old_value != new_value:
changes[field] = {"old": str(old_value), "new": str(new_value)}
except AttributeError:
continue
return changes
class HistoricalModel(models.Model):
"""
Legacy abstract base class for models with history tracking.
Use TrackedModel for new implementations.
"""
id = models.BigAutoField(primary_key=True)
history: HistoricalRecords = HistoricalRecords(
inherit=True,
bases=(HistoricalChangeMixin,)
)
class Meta:
abstract = True
@property
def _history_model(self) -> Type[T]:
"""Get the history model class"""
return cast(Type[T], self.history.model) # type: ignore
def get_history(self) -> QuerySet:
"""Get all history records for this instance"""
model = self._history_model
return model.objects.filter(id=self.pk).order_by('-history_date')
class TrackedModel(models.Model):
"""Abstract base class for models with pghistory tracking.
The @pghistory.track() decorator should be applied to concrete models
that inherit from this class.
"""
id = models.BigAutoField(primary_key=True)
class Meta:
abstract = True
def get_history(self) -> QuerySet:
"""Get all history records for this instance in chronological order"""
history_model = self.get_history_model()
return history_model.objects.filter(
pgh_obj_id=self.pk
).order_by('-pgh_created_at')
def get_history_model(self) -> Type[Any]:
"""Get the pghistory model for this instance"""
return self.pgh_obj_event_model
class HistoricalSlug(models.Model):
"""Track historical slugs for models"""
content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
object_id = models.PositiveIntegerField()
content_object = GenericForeignKey('content_type', 'object_id')
slug = models.SlugField(max_length=255)
created_at = models.DateTimeField(auto_now_add=True)
class Meta:
unique_together = ('content_type', 'slug')
indexes = [
models.Index(fields=['content_type', 'object_id']),
models.Index(fields=['slug']),
]
def __str__(self) -> str:
return f"{self.content_type} - {self.object_id} - {self.slug}"