Add caching and group detection for series images in series viewer

atlas/models.py

@@ -10,6 +10,8 @@ from rad.settings import REMOTE_URL
 from django.db.models.fields.files import ImageField
 from django.db.models.fields.related import ForeignKey
 from django.db import models
+from django.db.models.signals import pre_save, post_save, post_delete
+from django.dispatch import receiver
 from django.shortcuts import get_object_or_404
 from django.utils import timezone
 from django.core.cache import cache
@@ -129,11 +131,34 @@ def _normalise_group_rule_value(value):
         return text
 
 
+def _series_declared_groups_cache_key(series_id):
+    return f"atlas:series_declared_groups:{series_id}"
+
+
+def invalidate_series_declared_groups_cache(series_id):
+    if not series_id:
+        return
+    cache.delete(_series_declared_groups_cache_key(series_id))
+
+
 def _build_declared_series_groups(series, series_images_with_urls):
-    cache_key = f"atlas:series_declared_groups:{series.pk}:{int(series.modified_date.timestamp())}:{len(series_images_with_urls)}"
+    cache_key = _series_declared_groups_cache_key(series.pk)
+    signature = {
+        "series_modified": int(series.modified_date.timestamp()) if getattr(series, "modified_date", None) else 0,
+        "image_count": len(series_images_with_urls),
+        "images": [
+            {
+                "pk": getattr(image_obj, "pk", None),
+                "position": getattr(image_obj, "position", None),
+                "url": image_url,
+            }
+            for image_obj, image_url in series_images_with_urls
+        ],
+    }
     cached = cache.get(cache_key)
-    if cached is not None:
-        return cached
+    if isinstance(cached, dict):
+        if cached.get("signature") == signature:
+            return cached.get("groups", [])
 
     rules = [
         "dwiBValue",
@@ -232,7 +257,7 @@ def _build_declared_series_groups(series, series_images_with_urls):
                 "groupValues": {},
             }
         ]
-        cache.set(cache_key, result, timeout=60 * 60)
+        cache.set(cache_key, {"signature": signature, "groups": result}, timeout=60 * 60)
         return result
 
     grouped = {}
@@ -288,7 +313,7 @@ def _build_declared_series_groups(series, series_images_with_urls):
             }
         )
 
-    cache.set(cache_key, ordered_groups, timeout=60 * 60)
+    cache.set(cache_key, {"signature": signature, "groups": ordered_groups}, timeout=60 * 60)
     return ordered_groups
 
 
@@ -1274,6 +1299,42 @@ class SeriesImage(SeriesImageBase):
     #        }}
 
 
+@receiver(pre_save, sender=SeriesImage)
+def _capture_previous_series_for_series_image(sender, instance, **kwargs):
+    if not getattr(instance, "pk", None):
+        instance._previous_series_id_for_cache = None
+        return
+    previous_series_id = (
+        sender.objects.filter(pk=instance.pk).values_list("series_id", flat=True).first()
+    )
+    instance._previous_series_id_for_cache = previous_series_id
+
+
+def _invalidate_and_touch_series(series_id):
+    if not series_id:
+        return
+    invalidate_series_declared_groups_cache(series_id)
+    Series.objects.filter(pk=series_id).update(modified_date=timezone.now())
+
+
+@receiver(post_save, sender=SeriesImage)
+def _invalidate_declared_groups_on_series_image_save(sender, instance, **kwargs):
+    affected_series_ids = set()
+    if instance.series_id:
+        affected_series_ids.add(instance.series_id)
+    previous_series_id = getattr(instance, "_previous_series_id_for_cache", None)
+    if previous_series_id:
+        affected_series_ids.add(previous_series_id)
+
+    for series_id in affected_series_ids:
+        _invalidate_and_touch_series(series_id)
+
+
+@receiver(post_delete, sender=SeriesImage)
+def _invalidate_declared_groups_on_series_image_delete(sender, instance, **kwargs):
+    _invalidate_and_touch_series(getattr(instance, "series_id", None))
+
+
 class SeriesFinding(FindingBase):
     series = models.ForeignKey(
         "Series", related_name="findings", on_delete=models.SET_NULL, null=True