initial commit

apps/products/signals.py

@@ -0,0 +1,37 @@
+from django.db.models.signals import post_delete, pre_save
+from django.dispatch import receiver
+
+from .models import SubProductVersion
+from .release_assets import RELEASE_FILE_BY_URL_FIELD
+
+
+def _stored_release_file_name(version, file_field):
+    release_file = getattr(version, file_field)
+    return release_file.name if release_file else ""
+
+
+def _delete_release_file_from_disk(version, file_field):
+    release_file = getattr(version, file_field)
+    if release_file:
+        release_file.delete(save=False)
+
+
+@receiver(pre_save, sender=SubProductVersion)
+def delete_replaced_or_cleared_release_files(sender, instance, **kwargs):
+    if not instance.pk:
+        return
+    try:
+        previous = SubProductVersion.objects.get(pk=instance.pk)
+    except SubProductVersion.DoesNotExist:
+        return
+    for file_field in RELEASE_FILE_BY_URL_FIELD.values():
+        old_name = _stored_release_file_name(previous, file_field)
+        new_name = _stored_release_file_name(instance, file_field)
+        if old_name and old_name != new_name:
+            _delete_release_file_from_disk(previous, file_field)
+
+
+@receiver(post_delete, sender=SubProductVersion)
+def delete_release_files_on_version_delete(sender, instance, **kwargs):
+    for file_field in RELEASE_FILE_BY_URL_FIELD.values():
+        _delete_release_file_from_disk(instance, file_field)