Cache album cover data

gallery/templatetags/image_tags.py

@@ -1,29 +1,32 @@
 from math import floor
 
 from django import template
+from django.core.cache import cache
 from django.templatetags.static import static
 
 register = template.Library()
 
 @register.filter
 def cover_image_data(album):
-    """
-    Palauttaa dictin: url, width, height, aspect_ratio.
-    Jos coveria ei ole, palauttaa placeholder-kuvan ja oletusmitat.
-    """
+
+    cache_key = f'cover_image_data_{album.pk}'
+    data = cache.get(cache_key)
+
+    if data:
+        return data
+
     photo = getattr(album, "cover", None)
     max_w, max_h = 720, 720
 
     if not photo or not photo.width or not photo.height:
-        return {
+        data = {
             "url": static("img/placeholder.png"),
             "width": 1200,
             "height": 800,
             "aspect_ratio": round(1200 / 800, 3),
         }
-
+    else:
         aspect = photo.aspect_ratio
-
         if photo.width > photo.height:
             w = min(photo.width, max_w)
             h = floor(w / aspect)
@@ -31,9 +34,12 @@ def cover_image_data(album):
             h = min(photo.height, max_h)
             w = floor(h * aspect)
 
-    return {
+        data = {
             "url": photo.photo_md.url,
             "width": w,
             "height": h,
             "aspect_ratio": round(aspect, 3),
         }
+
+    cache.set(cache_key, data, 60 * 60 * 24)
+    return data