Automatically resize album thumbnail

sas/forms.py

@@ -1,16 +1,23 @@
-from typing import Any
+import copy
+from pathlib import Path
+from typing import TYPE_CHECKING, Any
 
 from django import forms
 from django.core.exceptions import ValidationError
 from django.utils.translation import gettext_lazy as _
+from PIL import Image
 
 from core.models import User
+from core.utils import resize_image
 from core.views import MultipleImageField
 from core.views.forms import SelectDate
 from core.views.widgets.ajax_select import AutoCompleteSelectMultipleGroup
 from sas.models import Album, Picture, PictureModerationRequest
 from sas.widgets.ajax_select import AutoCompleteSelectAlbum
 
+if TYPE_CHECKING:
+    from django.db.models.fields.files import FieldFile
+
 
 class AlbumCreateForm(forms.ModelForm):
     class Meta:
@@ -49,17 +56,45 @@ class AlbumEditForm(forms.ModelForm):
     class Meta:
         model = Album
         fields = ["name", "date", "file", "parent", "edit_groups"]
-        widgets = {
-            "edit_groups": AutoCompleteSelectMultipleGroup,
-        }
+        widgets = {"edit_groups": AutoCompleteSelectMultipleGroup, "date": SelectDate}
 
     name = forms.CharField(max_length=Album.NAME_MAX_LENGTH, label=_("file name"))
-    date = forms.DateField(label=_("Date"), widget=SelectDate, required=True)
     recursive = forms.BooleanField(label=_("Apply rights recursively"), required=False)
     parent = forms.ModelChoiceField(
         Album.objects.all(), required=True, widget=AutoCompleteSelectAlbum
     )
 
+    def clean_file(self):
+        # if a file was given in the form, resize it
+        f: FieldFile = self.cleaned_data["file"]
+        if self.errors or not f or "file" not in self.changed_data:
+            return f
+        f.file = resize_image(Image.open(f.file), 200, "WEBP")
+        return f
+
+    def save(self, commit=True):  # noqa: FBT002
+        initial_file = copy.copy(self.initial["file"])
+        if not self.cleaned_data["file"]:
+            # if no file is in the form, it can mean either :
+            # - there was a file initially, but the deletion box was checked
+            # - there was no file initially, and there still isn't
+            # in both cases, we procedurally generate the thumbnail
+            self.instance.generate_thumbnail()
+        elif "file" in self.changed_data:
+            self.instance.file.name = str(Path(self.instance.name) / "thumb.webp")
+        res = super().save(commit=commit)
+        if initial_file and (
+            not self.instance.file or initial_file.path != self.instance.file.path
+        ):
+            # The initial file must be removed from storage
+            # AFTER the new one has been dealt with,
+            # in order to be sure that django will generate a different filename.
+            # Otherwise, the client cache wouldn't be properly busted.
+            # Even if there was no file, this operation cannot fail, because django
+            # will just silently return in that case.
+            initial_file.delete(save=False)
+        return res
+
 
 class PictureModerationRequestForm(forms.ModelForm):
     """Form to create a PictureModerationRequest.

sas/models.py

@@ -22,6 +22,7 @@ from typing import ClassVar, Self
 
 from django.conf import settings
 from django.core.cache import cache
+from django.core.files.base import ContentFile
 from django.db import models
 from django.db.models import Exists, OuterRef, Q
 from django.urls import reverse
@@ -110,7 +111,7 @@ class Picture(SasFile):
     def get_absolute_url(self):
         return reverse("sas:picture", kwargs={"picture_id": self.id})
 
-    def generate_thumbnails(self, *, overwrite=False):
+    def generate_thumbnails(self):
         im = Image.open(BytesIO(self.file.read()))
         with contextlib.suppress(Exception):
             im = exif_auto_rotate(im)
@@ -126,10 +127,6 @@ class Picture(SasFile):
         file = resize_image(im, max(im.size), extension, optimize=False)
         thumb = resize_image(im, 200, "webp")
         compressed = resize_image(im, 1200, "webp")
-        if overwrite:
-            self.file.delete()
-            self.thumbnail.delete()
-            self.compressed.delete()
         new_extension_name = str(Path(self.name).with_suffix(".webp"))
         self.file = file
         self.file.name = self.name
@@ -245,17 +242,12 @@ class Album(SasFile):
         return reverse("sas:album_preview", kwargs={"album_id": self.id})
 
     def generate_thumbnail(self):
-        p = (
-            self.children_pictures.order_by("?").first()
-            or self.children_albums.exclude(file=None)
-            .exclude(file="")
-            .order_by("?")
-            .first()
+        p = self.children_pictures.order_by("?").first()
+        if p and p.thumbnail:
+            image = ContentFile(
+                name=str(Path(self.name) / "thumb.webp"), content=p.thumbnail.read()
             )
-        if p and p.file:
-            image = resize_image(Image.open(BytesIO(p.file.read())), 200, "webp")
             self.file = image
-            self.file.name = f"{self.name}/thumb.webp"
             self.save()
 
 

sas/templates/sas/macros.jinja

@@ -2,19 +2,19 @@
   <a href="{{ url('sas:album', album_id=a.id) }}">
     {% if a.file %}
       {% set img = a.get_download_url() %}
-      {% set src = a.name %}
+      {% set alt = a.name %}
     {% elif a.children.filter(is_folder=False, is_moderated=True).exists() %}
       {% set picture = a.children.filter(is_folder=False).first().as_picture %}
       {% set img = picture.get_download_thumb_url()  %}
-      {% set src = picture.name %}
+      {% set alt = picture.name %}
     {% else %}
       {% set img = static('core/img/sas.jpg') %}
-      {% set src = "sas.jpg" %}
+      {% set alt = "sas.jpg" %}
     {% endif %}
     <div
       class="album{% if not a.is_moderated %} not_moderated{% endif %}"
     >
-      <img src="{{ img }}" alt="{{ src }}" loading="lazy" />
+      <img src="{{ img }}" alt="{{ alt }}" loading="lazy" />
       {% if not a.is_moderated %}
         <div class="overlay">&nbsp;</div>
         <div class="text">{% trans %}To be moderated{% endtrans %}</div>

sas/views.py

@@ -16,6 +16,7 @@ from typing import Any
 
 from django.conf import settings
 from django.contrib.auth.mixins import PermissionRequiredMixin
+from django.core.exceptions import PermissionDenied
 from django.db.models import Count, OuterRef, Subquery
 from django.http import Http404, HttpResponseRedirect
 from django.shortcuts import get_object_or_404, redirect
@@ -152,9 +153,8 @@ class AlbumView(CanViewMixin, UseFragmentsMixin, DetailView):
 
     def post(self, request, *args, **kwargs):
         self.object = self.get_object()
-        if not self.object.file:
-            self.object.generate_thumbnail()
-        if request.user.can_edit(self.object):  # Handle the copy-paste functions
+        if not request.user.can_edit(self.object):
+            raise PermissionDenied
         FileView.handle_clipboard(request, self.object)
         return HttpResponseRedirect(self.request.path)