Add fix for playlists with less than 100 videos

src/invidious.cr

@@ -390,13 +390,14 @@ get "/playlist" do |env|
   page = env.params.query["page"]?.try &.to_i?
   page ||= 1
 
+  playlist = fetch_playlist(plid)
+
   begin
-    videos = extract_playlist(plid, page)
+    videos = fetch_playlist_videos(plid, page, playlist.video_count)
   rescue ex
     error_message = ex.message
     next templated "error"
   end
-  playlist = fetch_playlist(plid)
 
   templated "playlist"
 end
@@ -2822,15 +2823,15 @@ get "/api/v1/playlists/:plid" do |env|
   page = env.params.query["page"]?.try &.to_i?
   page ||= 1
 
+  playlist = fetch_playlist(plid)
+
   begin
-    videos = extract_playlist(plid, page)
+    videos = fetch_playlist_videos(plid, page, playlist.video_count)
   rescue ex
     error_message = {"error" => "Playlist is empty"}.to_json
     halt env, status_code: 404, response: error_message
   end
 
-  playlist = fetch_playlist(plid)
-
   response = JSON.build do |json|
     json.object do
       json.field "title", playlist.title

src/invidious/playlists.cr

@@ -25,23 +25,41 @@ class PlaylistVideo
   })
 end
 
-def extract_playlist(plid, page)
+def fetch_playlist_videos(plid, page, video_count)
+  client = make_client(YT_URL)
+
+  if video_count > 100
     index = (page - 1) * 100
     url = produce_playlist_url(plid, index)
 
-  client = make_client(YT_URL)
     response = client.get(url)
     response = JSON.parse(response.body)
     if !response["content_html"]? || response["content_html"].as_s.empty?
-    raise "Playlist does not exist"
+      raise "Playlist is empty"
     end
 
+    document = XML.parse_html(response["content_html"].as_s)
+    nodeset = document.xpath_nodes(%q(.//tr[contains(@class, "pl-video")]))
+    videos = extract_playlist(plid, nodeset, index)
+  else
+    if page > 1
+      videos = [] of PlaylistVideo
+    else
+      response = client.get("/playlist?list=#{plid}&disable_polymer=1")
+      document = XML.parse_html(response.body)
+      nodeset = document.xpath_nodes(%q(.//tr[contains(@class, "pl-video")]))
+
+      videos = extract_playlist(plid, nodeset, 0)
+    end
+  end
+
+  return videos
+end
+
+def extract_playlist(plid, nodeset, index)
   videos = [] of PlaylistVideo
 
-  document = XML.parse_html(response["content_html"].as_s)
-  anchor = document.xpath_node(%q(//div[@class="pl-video-owner"]/a))
-  if anchor
-    document.xpath_nodes(%q(.//tr[contains(@class, "pl-video")])).each_with_index do |video, offset|
+  nodeset.each_with_index do |video, offset|
     anchor = video.xpath_node(%q(.//td[@class="pl-video-title"]))
     if !anchor
       next
@@ -77,7 +95,6 @@ def extract_playlist(plid, page)
       index + offset,
     )
   end
-  end
 
   return videos
 end
@@ -112,13 +129,18 @@ def produce_playlist_url(id, index)
   continuation = Base64.urlsafe_encode(continuation)
   continuation = URI.escape(continuation)
 
-  url = "/browse_ajax?action_continuation=1&continuation=#{continuation}"
+  url = "/browse_ajax?continuation=#{continuation}"
 
   return url
 end
 
 def fetch_playlist(plid)
   client = make_client(YT_URL)
+
+  if plid.starts_with? "UC"
+    plid = "UU#{plid.lchop("UC")}"
+  end
+
   response = client.get("/playlist?list=#{plid}&disable_polymer=1")
   body = response.body.gsub(<<-END_BUTTON
   <button class="yt-uix-button yt-uix-button-size-default yt-uix-button-link yt-uix-expander-head playlist-description-expander yt-uix-inlineedit-ignore-edit" type="button" onclick=";return false;"><span class="yt-uix-button-content">  less <img alt="" src="/yts/img/pixel-vfl3z5WfW.gif">