Image handling refined (filenames, mobile rendering)

boxes/models.py

@@ -1,7 +1,19 @@
+import os
 from django.db import models
+from django.utils.text import slugify
 from mptt.models import MPTTModel, TreeForeignKey
 
 
+def thing_picture_upload_path(instance, filename):
+    """Generate a custom path for thing pictures in format: <id>-<name>.<extension>"""
+    extension = os.path.splitext(filename)[1]
+    safe_name = slugify(instance.name)
+    if instance.pk:
+        return f'things/{instance.pk}-{safe_name}{extension}'
+    else:
+        return f'things/temp-{safe_name}{extension}'
+
+
 class BoxType(models.Model):
     """A type of storage box with specific dimensions."""
 
@@ -72,10 +84,29 @@ class Thing(models.Model):
         related_name='things'
     )
     description = models.TextField(blank=True)
-    picture = models.ImageField(upload_to='things/', blank=True)
+    picture = models.ImageField(upload_to=thing_picture_upload_path, blank=True)
 
     class Meta:
         ordering = ['name']
 
+    def save(self, *args, **kwargs):
+        """Override save to rename picture file after instance gets a pk."""
+        if self.picture and not self.pk:
+            picture = self.picture
+            super().save(*args, **kwargs)
+            new_path = thing_picture_upload_path(self, picture.name)
+            if picture.name != new_path:
+                try:
+                    old_path = self.picture.path
+                    if os.path.exists(old_path):
+                        new_full_path = os.path.join(os.path.dirname(old_path), os.path.basename(new_path))
+                        os.rename(old_path, new_full_path)
+                        self.picture.name = new_path
+                        super().save(update_fields=['picture'])
+                except (AttributeError, FileNotFoundError):
+                    pass
+        else:
+            super().save(*args, **kwargs)
+
     def __str__(self):
         return self.name