Add pagination to subscriptions page

youtube/subscriptions.py

@@ -11,6 +11,7 @@ import traceback
 import contextlib
 import defusedxml.ElementTree
 import urllib
+import math
 
 import flask
 from flask import request
@@ -121,7 +122,16 @@ def _unsubscribe(cursor, channel_ids):
     gevent.spawn(delete_thumbnails, to_delete)
     cursor.executemany("DELETE FROM subscribed_channels WHERE yt_channel_id=?", ((channel_id, ) for channel_id in channel_ids))
 
-def _get_videos(cursor, number, offset, tag = None):
+def _get_videos(cursor, number_per_page, offset, tag = None):
+    '''Returns a full page of videos with an offset, and a value good enough to be used as the total number of videos'''
+    # We ask for the next 9 pages from the database
+    # Then the actual length of the results tell us if there are more than 9 pages left, and if not, how many there actually are
+    # This is done since there are only 9 page buttons on display at a time
+    # If there are more than 9 pages left, we give a fake value in place of the real number of results if the entire database was queried without limit
+    # This fake value is sufficient to get the page button generation macro to display 9 page buttons
+    # If we wish to display more buttons this logic must change
+    # We cannot use tricks with the sql id for the video since we frequently have filters and other restrictions in place on the results anyway
+    # TODO: This is probably not the ideal solution
     if tag is not None:
         db_videos = cursor.execute('''SELECT video_id, title, duration, channel_name
                                       FROM videos
@@ -129,21 +139,29 @@ def _get_videos(cursor, number, offset, tag = None):
                                       INNER JOIN tag_associations on videos.sql_channel_id = tag_associations.sql_channel_id
                                       WHERE tag = ?
                                       ORDER BY time_published DESC
-                                      LIMIT ? OFFSET ?''', (tag, number, offset))
+                                      LIMIT ? OFFSET ?''', (tag, number_per_page*9, offset)).fetchall()
     else:
         db_videos = cursor.execute('''SELECT video_id, title, duration, channel_name
                                       FROM videos
                                       INNER JOIN subscribed_channels on videos.sql_channel_id = subscribed_channels.id
                                       ORDER BY time_published DESC
-                                      LIMIT ? OFFSET ?''', (number, offset))
+                                      LIMIT ? OFFSET ?''', (number_per_page*9, offset)).fetchall()
 
-    for db_video in db_videos:
+    pseudo_number_of_videos = offset + len(db_videos)
-        yield {
+
+    videos = []
+    for db_video in db_videos[0:number_per_page]:
+        videos.append({
             'id':   db_video[0],
             'title':    db_video[1],
             'duration': db_video[2],
             'author':   db_video[3],
-        }
+        })
+
+    return videos, pseudo_number_of_videos
+
+
+
 
 def _get_subscribed_channels(cursor):
     for item in cursor.execute('''SELECT channel_name, yt_channel_id, muted
@@ -489,16 +507,16 @@ def post_subscription_manager_page():
 @yt_app.route('/subscriptions', methods=['GET'])
 @yt_app.route('/feed/subscriptions', methods=['GET'])
 def get_subscriptions_page():
+    page = int(request.args.get('page', 1))
     with open_database() as connection:
         with connection as cursor:
             tag = request.args.get('tag', None)
-            videos = []
+            videos, number_of_videos_in_db = _get_videos(cursor, 60, (page - 1)*60, tag)
-            for video in _get_videos(cursor, 60, 0, tag):
+            for video in videos:
                 video['thumbnail'] = util.URL_ORIGIN + '/data/subscription_thumbnails/' + video['id'] + '.jpg'
                 video['type'] = 'video'
                 video['item_size'] = 'small'
                 yt_data_extract.add_extra_html_info(video)
-                videos.append(video)
 
             tags = _get_all_tags(cursor)
 
@@ -514,6 +532,8 @@ def get_subscriptions_page():
 
     return flask.render_template('subscriptions.html',
         videos = videos,
+        num_pages = math.ceil(number_of_videos_in_db/60),
+        parameters_dictionary = request.args,
         tags = tags,
         subscription_list = subscription_list,
     )

youtube/templates/subscriptions.html

@@ -7,9 +7,12 @@
         display:flex;
         flex-direction: row;
     }
-    .item-grid{
+    .video-section{
         flex-grow: 1;
     }
+        .video-section .page-button-row{
+            justify-content: center;
+        }
     .subscriptions-sidebar{
         flex-basis: 300px;
         background-color: #dadada;
@@ -44,12 +47,18 @@
 {% endblock style %}
 
 {% block main %}
+    <div class="video-section">
         <nav class="item-grid">
             {% for video_info in videos %}
                 {{ common_elements.item(video_info, include_author=false) }}
             {% endfor %}
         </nav>
 
+        <nav class="page-button-row">
+            {{ common_elements.page_buttons(num_pages, '/youtube.com/subscriptions', parameters_dictionary) }}
+        </nav>
+    </div>
+
     <div class="subscriptions-sidebar">
         <div class="sidebar-links">
             <a href="/youtube.com/subscription_manager" class="sub-manager-link">Subscription Manager</a>
@@ -91,7 +100,4 @@
 
     </div>
 
-    <nav class="page-button-row">
-        {# TODO #}
-    </nav>
 {% endblock main %}