themes/signals.py

from django.db.models.signals import pre_delete, pre_save
from django.dispatch import receiver
from .models import BottomBar, Setting
import os


@receiver(pre_delete, sender=BottomBar)
def bottombar_auto_delete_file_on_delete(instance: BottomBar, **kwargs):
    """
    Deletes file from filesystem
    when corresponding `BottomBar` object is deleted.
    """
    if instance.icon:
        if os.path.isfile(instance.icon.path):
            os.remove(instance.icon.path)


@receiver(pre_save, sender=BottomBar)
def bottombar_auto_delete_file_on_change(instance: BottomBar, **kwargs):
    """
    Deletes old file from filesystem
    when corresponding `icon` object is updated
    with new file.
    """
    if not instance.pk:
        return False

    try:
        old_file = BottomBar.objects.get(pk=instance.pk).icon
    except BottomBar.DoesNotExist:
        return False

    new_file = instance.icon
    if not old_file == new_file and old_file:
        if os.path.isfile(old_file.path):
            os.remove(old_file.path)


@receiver(pre_delete, sender=Setting)
def setting_auto_delete_file_on_delete(instance: Setting, **kwargs):
    """
    Deletes file from filesystem
    when corresponding `Settings` object is deleted.
    """
    if instance.page_image.path.endswith(instance.page_image.field.default):
        return False

    if instance.page_image:
        if os.path.isfile(instance.page_image.path):
            os.remove(instance.page_image.path)


@receiver(pre_save, sender=Setting)
def setting_auto_delete_file_on_change(instance: Setting, **kwargs):
    """
    Deletes old file from filesystem
    when corresponding `page_image` object is updated
    with new file.
    """
    if not instance.pk:
        return False

    try:
        old_file = Setting.objects.get(pk=instance.pk).page_image
    except Setting.DoesNotExist:
        return False

    if old_file.path.endswith(instance.page_image.field.default):
        return False

    new_file = instance.page_image
    if not old_file == new_file:
        if os.path.isfile(old_file.path):
            os.remove(old_file.path)