F(backend): add public media derivatives pipeline

apps/gallery/models.py

@@ -1,13 +1,14 @@
 from django.db import models
 from django.conf import settings
 
-from PIL import Image
-
 from core.models import BaseModel
+from core.media import (
+    delete_image_derivatives_by_name,
+    get_image_previous_name,
+    safe_process_public_image,
+)
 
 
-MAX_IMAGE_FILE_SIZE_BYTES = 2 * 1024 * 1024
-
 class Gallery(BaseModel):
     title = models.CharField(max_length=200)
     description = models.TextField(blank=True)
@@ -27,47 +28,39 @@ class Gallery(BaseModel):
         return self.title
 
     def save(self, *args, **kwargs):
+        previous_image_name = get_image_previous_name(self, "image")
+        current_image_name = self.image.name if self.image else None
+        image_changed = previous_image_name != current_image_name
+
         super().save(*args, **kwargs)
-        
-        if self.image:
-            # Get file size
-            self.file_size = self.image.size
-            
-            # Get image dimensions
-            with Image.open(self.image.path) as img:
-                self.width, self.height = img.size
-            
-            # Compress image if it's too large
-            self.compress_image()
-            
-            # Update fields without triggering save again
-            Gallery.objects.filter(pk=self.pk).update(
-                file_size=self.file_size,
-                width=self.width,
-                height=self.height
+
+        if image_changed and previous_image_name:
+            delete_image_derivatives_by_name(
+                self.image.storage if self.image else None,
+                previous_image_name,
+                "gallery",
+                delete_original=True,
             )
 
-    def compress_image(self):
-        """Compress image if it's larger than 2MB or dimensions are too large"""
         if not self.image:
+            if image_changed:
+                Gallery.objects.filter(pk=self.pk).update(file_size=None, width=None, height=None)
             return
-            
-        with Image.open(self.image.path) as img:
-            # Convert to RGB if necessary
-            if img.mode in ("RGBA", "P"):
-                img = img.convert("RGB")
-            
-            # Resize if too large
-            max_size = (1920, 1080)
-            if img.size[0] > max_size[0] or img.size[1] > max_size[1]:
-                img.thumbnail(max_size, Image.Resampling.LANCZOS)
-            
-            # Compress if file size is too large
-            quality = 85
-        if self.file_size and self.file_size > MAX_IMAGE_FILE_SIZE_BYTES:
-            quality = 70
-            
-            img.save(self.image.path, "JPEG", quality=quality, optimize=True)
+
+        if getattr(self, "_defer_image_processing", False):
+            return
+
+        if image_changed:
+            result = safe_process_public_image(self.image, "gallery")
+            if result:
+                Gallery.objects.filter(pk=self.pk).update(
+                    file_size=result.file_size,
+                    width=result.width,
+                    height=result.height,
+                )
+                self.file_size = result.file_size
+                self.width = result.width
+                self.height = result.height
 
     @property
     def file_size_mb(self):