Simplified thumbnail logic, only the best thumbnail size is downloaded and then it is resized and cropped to an appropriate size for use in the web UI.

app/YtManager/settings.py

@@ -105,6 +105,9 @@ USE_L10N = True
 
 USE_TZ = True
 
+# Thumbnails
+THUMBNAIL_SIZE_VIDEO = (410, 230)
+THUMBNAIL_SIZE_SUBSCRIPTION = (250, 250)
 
 # Static files (CSS, JavaScript, Images)
 # https://docs.djangoproject.com/en/1.11/howto/static-files/

app/YtManagerApp/management/downloader.py

@@ -6,6 +6,8 @@ import logging
 import requests
 import mimetypes
 import os
+import PIL.Image
+import PIL.ImageOps
 from urllib.parse import urljoin
 
 log = logging.getLogger('downloader')
@@ -61,9 +63,9 @@ def downloader_process_all():
         downloader_process_subscription(subscription)
 
 
-def fetch_thumbnail(url, object_type, identifier, quality):
+def fetch_thumbnail(url, object_type, identifier, thumb_size):
 
-    log.info('Fetching thumbnail url=%s object_type=%s identifier=%s quality=%s', url, object_type, identifier, quality)
+    log.info('Fetching thumbnail url=%s object_type=%s identifier=%s', url, object_type, identifier)
 
     # Make request to obtain mime type
     try:
@@ -75,17 +77,28 @@ def fetch_thumbnail(url, object_type, identifier, quality):
     ext = mimetypes.guess_extension(response.headers['Content-Type'])
 
     # Build file path
-    file_name = f"{identifier}-{quality}{ext}"
+    file_name = f"{identifier}{ext}"
     abs_path_dir = os.path.join(srv_settings.MEDIA_ROOT, "thumbs", object_type)
     abs_path = os.path.join(abs_path_dir, file_name)
+    abs_path_tmp = file_name + '.tmp'
 
     # Store image
     try:
         os.makedirs(abs_path_dir, exist_ok=True)
-        with open(abs_path, "wb") as f:
+        with open(abs_path_tmp, "wb") as f:
             for chunk in response.iter_content(chunk_size=1024):
                 if chunk:
                     f.write(chunk)
+
+        # Resize and crop to thumbnail size
+        image = PIL.Image.open(abs_path_tmp)
+        image = PIL.ImageOps.fit(image, thumb_size)
+        image.save(abs_path)
+        image.close()
+
+        # Delete temp file
+        os.unlink(abs_path_tmp)
+
     except requests.exceptions.RequestException as e:
         log.error('Error while downloading stream for thumbnail %s. Error: %s', url, e)
         return url

app/YtManagerApp/management/jobs/synchronize.py

@@ -4,6 +4,7 @@ from threading import Lock
 
 from apscheduler.triggers.cron import CronTrigger
 from django.db.models import Max
+from django.conf import settings
 
 from YtManagerApp.management.appconfig import appconfig
 from YtManagerApp.management.downloader import fetch_thumbnail, downloader_process_subscription
@@ -110,21 +111,13 @@ class SynchronizeJob(Job):
 
                 self.__new_vids.append(Video.create(item, sub))
 
-    def fetch_missing_thumbnails(self, object: Union[Subscription, Video]):
-        if isinstance(object, Subscription):
-            object_type = "sub"
-            object_id = object.playlist_id
-        else:
-            object_type = "video"
-            object_id = object.video_id
-
-        if object.icon_default.startswith("http"):
-            object.icon_default = fetch_thumbnail(object.icon_default, object_type, object_id, 'default')
-            object.save()
-
-        if object.icon_best.startswith("http"):
-            object.icon_best = fetch_thumbnail(object.icon_best, object_type, object_id, 'best')
-            object.save()
+    def fetch_missing_thumbnails(self, obj: Union[Subscription, Video]):
+        if obj.thumbnail.startswith("http"):
+            if isinstance(obj, Subscription):
+                obj.thumbnail = fetch_thumbnail(obj.thumbnail, 'sub', obj.playlist_id, settings.THUMBNAIL_SIZE_SUBSCRIPTION)
+            elif isinstance(obj, Video):
+                obj.thumbnail = fetch_thumbnail(obj.thumbnail, 'video', obj.video_id, settings.THUMBNAIL_SIZE_VIDEO)
+            obj.save()
 
     def check_video_deleted(self, video: Video):
         if video.downloaded_path is not None:

app/YtManagerApp/migrations/0011_auto_20190819_1613.py

@@ -0,0 +1,21 @@
+# Generated by Django 2.2.4 on 2019-08-19 16:13
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('YtManagerApp', '0010_auto_20190819_1317'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='subscription',
+            name='icon_default',
+        ),
+        migrations.RemoveField(
+            model_name='video',
+            name='icon_default',
+        ),
+    ]

app/YtManagerApp/migrations/0012_auto_20190819_1615.py

@@ -0,0 +1,23 @@
+# Generated by Django 2.2.4 on 2019-08-19 16:15
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('YtManagerApp', '0011_auto_20190819_1613'),
+    ]
+
+    operations = [
+        migrations.RenameField(
+            model_name='subscription',
+            old_name='icon_best',
+            new_name='thumbnail',
+        ),
+        migrations.RenameField(
+            model_name='video',
+            old_name='icon_best',
+            new_name='thumbnail',
+        ),
+    ]

app/YtManagerApp/models.py

@@ -106,8 +106,7 @@ class Subscription(models.Model):
     description = models.TextField()
     channel_id = models.CharField(max_length=128)
     channel_name = models.CharField(max_length=1024)
-    icon_default = models.CharField(max_length=1024)
-    icon_best = models.CharField(max_length=1024)
+    thumbnail = models.CharField(max_length=1024)
     user = models.ForeignKey(User, on_delete=models.CASCADE)
     # youtube adds videos to the 'Uploads' playlist at the top instead of the bottom
     rewrite_playlist_indices = models.BooleanField(null=False, default=False)
@@ -133,8 +132,7 @@ class Subscription(models.Model):
         self.description = info_playlist.description
         self.channel_id = info_playlist.channel_id
         self.channel_name = info_playlist.channel_title
-        self.icon_default = youtube.default_thumbnail(info_playlist).url
-        self.icon_best = youtube.best_thumbnail(info_playlist).url
+        self.thumbnail = youtube.best_thumbnail(info_playlist).url
 
     def copy_from_channel(self, info_channel: youtube.Channel):
         # No point in storing info about the 'uploads from X' playlist
@@ -143,8 +141,7 @@ class Subscription(models.Model):
         self.description = info_channel.description
         self.channel_id = info_channel.id
         self.channel_name = info_channel.title
-        self.icon_default = youtube.default_thumbnail(info_channel).url
-        self.icon_best = youtube.best_thumbnail(info_channel).url
+        self.thumbnail = youtube.best_thumbnail(info_channel).url
         self.rewrite_playlist_indices = True
 
     def fetch_from_url(self, url, yt_api: youtube.YoutubeAPI):
@@ -176,8 +173,7 @@ class Video(models.Model):
     subscription = models.ForeignKey(Subscription, on_delete=models.CASCADE)
     playlist_index = models.IntegerField(null=False)
     publish_date = models.DateTimeField(null=False)
-    icon_default = models.TextField()
-    icon_best = models.TextField()
+    thumbnail = models.TextField()
     uploader_name = models.TextField(null=False)
     views = models.IntegerField(null=False, default=0)
     rating = models.FloatField(null=False, default=0.5)
@@ -194,8 +190,7 @@ class Video(models.Model):
         video.subscription = subscription
         video.playlist_index = playlist_item.position
         video.publish_date = playlist_item.published_at
-        video.icon_default = youtube.default_thumbnail(playlist_item).url
-        video.icon_best = youtube.best_thumbnail(playlist_item).url
+        video.thumbnail = youtube.best_thumbnail(playlist_item).url
         video.save()
         return video
 

app/YtManagerApp/templates/YtManagerApp/index_videos.html

@@ -7,7 +7,7 @@
             <div class="card-wrapper d-flex align-items-stretch" style="width: 18rem;">
                 <div class="card mx-auto">
                     <a href="{% url 'video' video.id %}" target="_blank">
-                        <img class="card-img-top" src="{{ video.icon_best }}" alt="Thumbnail">
+                        <img class="card-img-top" src="{{ video.thumbnail }}" alt="Thumbnail">
                     </a>
                     <div class="card-body">
                         <h5 class="card-title">

app/YtManagerApp/templates/YtManagerApp/video.html

@@ -37,7 +37,6 @@
                     {{ object.description | linebreaks | urlize }}
                 </div>
 
-                </p>
             </div>
 
             <div class="col-4">

app/YtManagerApp/views/index.py

@@ -144,7 +144,7 @@ def ajax_get_tree(request: HttpRequest):
                 "id": __tree_sub_id(node.id),
                 "type": "sub",
                 "text": node.name,
-                "icon": node.icon_default,
+                "icon": node.thumbnail,
                 "parent": __tree_folder_id(node.parent_folder_id)
             }
 

requirements.txt

@@ -1,3 +1,4 @@
+pytz
 requests
 apscheduler
 gunicorn
@@ -10,4 +11,5 @@ google-api-python-client
 google_auth_oauthlib 
 oauth2client
 psycopg2-binary
-python-dateutil
+python-dateutil
+Pillow