constants/base.py

@@ -106,6 +106,6 @@ ABUSE_TYPE = Choices(
 # the code expecting thumbnails of new dimensions can be deployed!
 THUMBNAIL_SIZE_L = (1920, 1080)
 THUMBNAIL_SIZE_S = (640, 360)
-THUMBNAIL_SIZES = [THUMBNAIL_SIZE_L, THUMBNAIL_SIZE_S]
+THUMBNAIL_SIZES = {'l': THUMBNAIL_SIZE_L, 's': THUMBNAIL_SIZE_S}
 THUMBNAIL_FORMAT = 'PNG'
 THUMBNAIL_QUALITY = 83

files/models.py

@@ -199,7 +199,11 @@ class File(CreatedModifiedMixin, TrackChangesMixin, models.Model):
 
     @property
     def thumbnail_l_url(self) -> str:
-        """Log absence of the thumbnail file instead of exploding somewhere in the templates."""
+        """Return absolute path portion of the URL of the large thumbnail of this file.
+
+        Fall back to the source file, if no thumbnail is stored.
+        Log absence of the thumbnail file instead of exploding somewhere in the templates.
+        """
         try:
             return self.thumbnail.url
         except ValueError:
@@ -208,11 +212,16 @@ class File(CreatedModifiedMixin, TrackChangesMixin, models.Model):
 
     @property
     def thumbnail_s_url(self) -> str:
-        """Log absence of the thumbnail file instead of exploding somewhere in the templates."""
+        """Return absolute path portion of the URL of the small thumbnail of this file.
+
+        Fall back to the source file, if no thumbnail is stored.
+        Log absence of the thumbnail file instead of exploding somewhere in the templates.
+        """
         try:
-            return self.metadata['thumbnails']['s']['path']
-        except KeyError:
-            log.exception(f'File pk={self.pk} is missing a small thumbnail')
+            s = self.metadata['thumbnails']['s']['path']
+            return self.thumbnail.storage.url(s)
+        except (KeyError, TypeError):
+            log.exception(f'File pk={self.pk} is missing a small thumbnail: {self.metadata}')
         return self.source.url
 
 

files/tasks.py

@@ -5,7 +5,6 @@ from background_task import background
 from background_task.tasks import TaskSchedule
 from django.conf import settings
 
-from constants.base import THUMBNAIL_SIZE_L
 import files.models
 import files.utils
 
@@ -32,7 +31,7 @@ def clamdscan(file_id: int):
 
 @background(schedule={'action': TaskSchedule.RESCHEDULE_EXISTING})
 def make_thumbnails(file_id: int) -> None:
-    """Generate thumbnails for a given file."""
+    """Generate thumbnails for a given file, store them in thumbnail and metadata columns."""
     file = files.models.File.objects.get(pk=file_id)
     args = {'pk': file_id, 'type': file.get_type_display()}
     if not file.is_image and not file.is_video:
@@ -51,7 +50,7 @@ def make_thumbnails(file_id: int) -> None:
         source_path = output_path
 
     thumbnails = files.utils.make_thumbnails(source_path, file.hash)
-    thumbnail_default_path = next(_['path'] for _ in thumbnails if _['size'] == THUMBNAIL_SIZE_L)
+    thumbnail_default_path = thumbnails['l']['path']
 
     update_fields = set()
     if thumbnail_default_path != thumbnail_field.name:

files/templates/files/admin/thumbnails.html

@@ -1,10 +1,12 @@
 <div class="file-thumbnails">
-{% for thumb in file.metadata.thumbnails %}
+{% for size_key, thumb in file.metadata.thumbnails.items %}
   <div class="file-thumbnail">
     <span class="file-thumbnail-size">{{ thumb.size.0 }}x{{ thumb.size.1 }}px</span>
     <img height="{% widthratio thumb.size.1 10 1 %}" src="{{ MEDIA_URL }}{{ thumb.path }}" title={{ thumb.path }}>
   </div>
 {% endfor %}
+{# alert about unexpected size of the default thumbnail, which might happen if source file was smaller than 1080p #}
+{# TODO: do we want to make minimum resolusion a validation criteria during upload instead? #}
 {% if file.thumbnail.width != THUMBNAIL_SIZE_L.0 or file.thumbnail.height != THUMBNAIL_SIZE_L.1 %}
   <p>
     <b class="icon-alert">⚠</b> Expected {{ THUMBNAIL_SIZE_L.0 }}x{{ THUMBNAIL_SIZE_L.1 }}px,

files/utils.py

@@ -227,14 +227,14 @@ def make_thumbnails(file_path: str, file_hash: str, output_format: str = THUMBNA
     """Generate thumbnail files for given file and a predefined list of dimensions.
 
     Resulting thumbnail paths a derived from the given file hash and thumbnail sizes.
-    Return a list of sizes and output paths of generated thumbnail images.
+    Return a dict of size keys to output paths of generated thumbnail images.
     """
     thumbnail_ext = output_format.lower()
     if thumbnail_ext == 'jpeg':
         thumbnail_ext = 'jpg'
     base_path = get_base_path(get_thumbnail_upload_to(file_hash))
-    thumbnails = []
-    for w, h in THUMBNAIL_SIZES:
+    thumbnails = {}
+    for size_key, (w, h) in THUMBNAIL_SIZES.items():
         output_path = f'{base_path}_{w}x{h}.{thumbnail_ext}'
         size = (w, h)
         with tempfile.TemporaryFile() as f:
@@ -255,7 +255,7 @@ def make_thumbnails(file_path: str, file_hash: str, output_format: str = THUMBNA
                 logger.warning('%s exists, overwriting', output_path)
                 default_storage.delete(output_path)
             default_storage.save(output_path, f)
-            thumbnails.append({'size': size, 'path': output_path})
+            thumbnails[size_key] = {'size': size, 'path': output_path}
     return thumbnails