cache data for xmltv (#1228)

* cache channel list for xmltv * used cached channel data for xmltv * fixes * update changelog
2023-04-03 23:09:54 -05:00
parent c9141b0d86
commit 9f42333465
18 changed files with 813 additions and 528 deletions
@@ -17,6 +17,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Changed
 - Use Poster artwork for XMLTV if available
  - If Poster artwork is unavailable, use Thumbnail
+- Improve XMLTV response time by caching data as playouts are updated 

 ## [0.7.6-beta] - 2023-03-24
 ### Added
@@ -0,0 +1,3 @@
+namespace ErsatzTV.Application.Channels;
+
+public record RefreshChannelData(string ChannelNumber) : IRequest, IBackgroundServiceRequest;
@@ -0,0 +1,521 @@
+using System.Xml;
+using ErsatzTV.Core;
+using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Domain.Filler;
+using ErsatzTV.Core.Emby;
+using ErsatzTV.Core.Interfaces.Metadata;
+using ErsatzTV.Core.Jellyfin;
+using ErsatzTV.Infrastructure.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+using Microsoft.IO;
+
+namespace ErsatzTV.Application.Channels;
+
+public class RefreshChannelDataHandler : IRequestHandler<RefreshChannelData>
+{
+    private readonly RecyclableMemoryStreamManager _recyclableMemoryStreamManager;
+    private readonly IDbContextFactory<TvContext> _dbContextFactory;
+    private readonly ILocalFileSystem _localFileSystem;
+    private readonly ILogger<RefreshChannelDataHandler> _logger;
+
+    public RefreshChannelDataHandler(
+        RecyclableMemoryStreamManager recyclableMemoryStreamManager,
+        IDbContextFactory<TvContext> dbContextFactory,
+        ILocalFileSystem localFileSystem,
+        ILogger<RefreshChannelDataHandler> logger)
+    {
+        _recyclableMemoryStreamManager = recyclableMemoryStreamManager;
+        _dbContextFactory = dbContextFactory;
+        _localFileSystem = localFileSystem;
+        _logger = logger;
+    }
+
+    public async Task Handle(RefreshChannelData request, CancellationToken cancellationToken)
+    {
+        _localFileSystem.EnsureFolderExists(FileSystemLayout.ChannelGuideCacheFolder);
+
+        await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
+
+        List<PlayoutItem> sorted = await dbContext.Playouts
+            .AsNoTracking()
+            .Filter(pi => pi.Channel.Number == request.ChannelNumber)
+            .Include(p => p.Items)
+            .ThenInclude(i => i.MediaItem)
+            .ThenInclude(i => (i as Episode).EpisodeMetadata)
+            .Include(p => p.Items)
+            .ThenInclude(i => i.MediaItem)
+            .ThenInclude(i => (i as Episode).Season)
+            .ThenInclude(s => s.Show)
+            .ThenInclude(s => s.ShowMetadata)
+            .ThenInclude(sm => sm.Artwork)
+            .Include(p => p.Items)
+            .ThenInclude(i => i.MediaItem)
+            .ThenInclude(i => (i as Episode).Season)
+            .ThenInclude(s => s.Show)
+            .ThenInclude(s => s.ShowMetadata)
+            .ThenInclude(em => em.Genres)
+            .Include(p => p.Items)
+            .ThenInclude(i => i.MediaItem)
+            .ThenInclude(i => (i as Movie).MovieMetadata)
+            .ThenInclude(mm => mm.Artwork)
+            .Include(p => p.Items)
+            .ThenInclude(i => i.MediaItem)
+            .ThenInclude(i => (i as Movie).MovieMetadata)
+            .ThenInclude(mm => mm.Genres)
+            .Include(p => p.Items)
+            .ThenInclude(i => i.MediaItem)
+            .ThenInclude(i => (i as MusicVideo).MusicVideoMetadata)
+            .ThenInclude(mm => mm.Artwork)
+            .Include(p => p.Items)
+            .ThenInclude(i => i.MediaItem)
+            .ThenInclude(i => (i as MusicVideo).MusicVideoMetadata)
+            .ThenInclude(mvm => mvm.Genres)
+            .Include(p => p.Items)
+            .ThenInclude(i => i.MediaItem)
+            .ThenInclude(i => (i as MusicVideo).Artist)
+            .ThenInclude(a => a.ArtistMetadata)
+            .ThenInclude(am => am.Genres)
+            .Include(p => p.Items)
+            .ThenInclude(i => i.MediaItem)
+            .ThenInclude(i => (i as OtherVideo).OtherVideoMetadata)
+            .ThenInclude(vm => vm.Artwork)
+            .Include(p => p.Items)
+            .ThenInclude(i => i.MediaItem)
+            .ThenInclude(i => (i as Song).SongMetadata)
+            .ThenInclude(vm => vm.Artwork)
+            .ToListAsync(cancellationToken)
+            .Map(list => list.Collect(p => p.Items).OrderBy(pi => pi.Start).ToList());
+
+        using MemoryStream ms = _recyclableMemoryStreamManager.GetStream();
+        await using var xml = XmlWriter.Create(
+            ms,
+            new XmlWriterSettings { Async = true, ConformanceLevel = ConformanceLevel.Fragment });
+
+        // skip all filler that isn't pre-roll
+        var i = 0;
+        while (i < sorted.Count && sorted[i].FillerKind != FillerKind.None &&
+               sorted[i].FillerKind != FillerKind.PreRoll)
+        {
+            i++;
+        }
+
+        while (i < sorted.Count)
+        {
+            PlayoutItem startItem = sorted[i];
+            int j = i;
+            while (sorted[j].FillerKind != FillerKind.None && j + 1 < sorted.Count)
+            {
+                j++;
+            }
+
+            PlayoutItem displayItem = sorted[j];
+            bool hasCustomTitle = !string.IsNullOrWhiteSpace(startItem.CustomTitle);
+
+            int finishIndex = j;
+            while (finishIndex + 1 < sorted.Count && (sorted[finishIndex + 1].GuideGroup == startItem.GuideGroup
+                                                      || sorted[finishIndex + 1].FillerKind is FillerKind.GuideMode
+                                                          or FillerKind.Tail or FillerKind.Fallback))
+            {
+                finishIndex++;
+            }
+
+            int customShowId = -1;
+            if (displayItem.MediaItem is Episode ep)
+            {
+                customShowId = ep.Season.ShowId;
+            }
+
+            bool isSameCustomShow = hasCustomTitle;
+            for (int x = j; x <= finishIndex; x++)
+            {
+                isSameCustomShow = isSameCustomShow && sorted[x].MediaItem is Episode e &&
+                                   customShowId == e.Season.ShowId;
+            }
+
+            PlayoutItem finishItem = sorted[finishIndex];
+            i = finishIndex;
+
+            string start = startItem.StartOffset.ToString("yyyyMMddHHmmss zzz").Replace(":", string.Empty);
+            string stop = displayItem.GuideFinishOffset.HasValue
+                ? displayItem.GuideFinishOffset.Value.ToString("yyyyMMddHHmmss zzz").Replace(":", string.Empty)
+                : finishItem.FinishOffset.ToString("yyyyMMddHHmmss zzz").Replace(":", string.Empty);
+
+            string title = GetTitle(displayItem);
+            string subtitle = GetSubtitle(displayItem);
+            string description = GetDescription(displayItem);
+            Option<ContentRating> contentRating = GetContentRating(displayItem);
+
+            await xml.WriteStartElementAsync(null, "programme", null);
+            await xml.WriteAttributeStringAsync(null, "start", null, start);
+            await xml.WriteAttributeStringAsync(null, "stop", null, stop);
+            await xml.WriteAttributeStringAsync(null, "channel", null, $"{request.ChannelNumber}.etv");
+
+            await xml.WriteStartElementAsync(null, "title", null);
+            await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+            await xml.WriteStringAsync(title);
+            await xml.WriteEndElementAsync(); // title
+
+            if (!string.IsNullOrWhiteSpace(subtitle))
+            {
+                await xml.WriteStartElementAsync(null, "sub-title", null);
+                await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                await xml.WriteStringAsync(subtitle);
+                await xml.WriteEndElementAsync(); // subtitle
+            }
+
+            if (!isSameCustomShow)
+            {
+                if (!string.IsNullOrWhiteSpace(description))
+                {
+                    await xml.WriteStartElementAsync(null, "desc", null);
+                    await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                    await xml.WriteStringAsync(description);
+                    await xml.WriteEndElementAsync(); // desc
+                }
+            }
+
+            if (!hasCustomTitle && displayItem.MediaItem is Movie movie)
+            {
+                foreach (MovieMetadata metadata in movie.MovieMetadata.HeadOrNone())
+                {
+                    if (metadata.Year.HasValue)
+                    {
+                        await xml.WriteStartElementAsync(null, "date", null);
+                        await xml.WriteStringAsync(metadata.Year.Value.ToString());
+                        await xml.WriteEndElementAsync(); // date
+                    }
+
+                    await xml.WriteStartElementAsync(null, "category", null);
+                    await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                    await xml.WriteStringAsync("Movie");
+                    await xml.WriteEndElementAsync(); // category
+
+                    foreach (Genre genre in Optional(metadata.Genres).Flatten().OrderBy(g => g.Name))
+                    {
+                        await xml.WriteStartElementAsync(null, "category", null);
+                        await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                        await xml.WriteStringAsync(genre.Name);
+                        await xml.WriteEndElementAsync(); // category
+                    }
+
+                    string poster = Optional(metadata.Artwork).Flatten()
+                        .Filter(a => a.ArtworkKind == ArtworkKind.Poster)
+                        .HeadOrNone()
+                        .Match(a => GetArtworkUrl(a, ArtworkKind.Poster), () => string.Empty);
+
+                    if (!string.IsNullOrWhiteSpace(poster))
+                    {
+                        await xml.WriteStartElementAsync(null, "icon", null);
+                        await xml.WriteAttributeStringAsync(null, "src", null, poster);
+                        await xml.WriteEndElementAsync(); // icon
+                    }
+                }
+            }
+
+            if (!hasCustomTitle && displayItem.MediaItem is MusicVideo musicVideo)
+            {
+                foreach (MusicVideoMetadata metadata in musicVideo.MusicVideoMetadata.HeadOrNone())
+                {
+                    if (metadata.Year.HasValue)
+                    {
+                        await xml.WriteStartElementAsync(null, "date", null);
+                        await xml.WriteStringAsync(metadata.Year.Value.ToString());
+                        await xml.WriteEndElementAsync(); // date
+                    }
+
+                    await xml.WriteStartElementAsync(null, "category", null);
+                    await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                    await xml.WriteStringAsync("Music");
+                    await xml.WriteEndElementAsync(); // category
+
+                    // music video genres
+                    foreach (Genre genre in Optional(metadata.Genres).Flatten().OrderBy(g => g.Name))
+                    {
+                        await xml.WriteStartElementAsync(null, "category", null);
+                        await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                        await xml.WriteStringAsync(genre.Name);
+                        await xml.WriteEndElementAsync(); // category
+                    }
+
+                    // artist genres
+                    Option<ArtistMetadata> maybeMetadata =
+                        Optional(musicVideo.Artist?.ArtistMetadata.HeadOrNone()).Flatten();
+                    foreach (ArtistMetadata artistMetadata in maybeMetadata)
+                    {
+                        foreach (Genre genre in Optional(artistMetadata.Genres).Flatten().OrderBy(g => g.Name))
+                        {
+                            await xml.WriteStartElementAsync(null, "category", null);
+                            await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                            await xml.WriteStringAsync(genre.Name);
+                            await xml.WriteEndElementAsync(); // category
+                        }
+                    }
+
+                    string artworkPath = GetPrioritizedArtworkPath(metadata);
+                    if (!string.IsNullOrWhiteSpace(artworkPath))
+                    {
+                        await xml.WriteStartElementAsync(null, "icon", null);
+                        await xml.WriteAttributeStringAsync(null, "src", null, artworkPath);
+                        await xml.WriteEndElementAsync(); // icon
+                    }
+                }
+            }
+
+            if (!hasCustomTitle && displayItem.MediaItem is Song song)
+            {
+                await xml.WriteStartElementAsync(null, "category", null);
+                await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                await xml.WriteStringAsync("Music");
+                await xml.WriteEndElementAsync(); // category
+
+                foreach (SongMetadata metadata in song.SongMetadata.HeadOrNone())
+                {
+                    string artworkPath = GetPrioritizedArtworkPath(metadata);
+                    if (!string.IsNullOrWhiteSpace(artworkPath))
+                    {
+                        await xml.WriteStartElementAsync(null, "icon", null);
+                        await xml.WriteAttributeStringAsync(null, "src", null, artworkPath);
+                        await xml.WriteEndElementAsync(); // icon
+                    }
+                }
+            }
+
+            if (displayItem.MediaItem is Episode episode && (!hasCustomTitle || isSameCustomShow))
+            {
+                Option<ShowMetadata> maybeMetadata =
+                    Optional(episode.Season?.Show?.ShowMetadata.HeadOrNone()).Flatten();
+                foreach (ShowMetadata metadata in maybeMetadata)
+                {
+                    await xml.WriteStartElementAsync(null, "category", null);
+                    await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                    await xml.WriteStringAsync("Series");
+                    await xml.WriteEndElementAsync(); // category
+
+                    foreach (Genre genre in Optional(metadata.Genres).Flatten().OrderBy(g => g.Name))
+                    {
+                        await xml.WriteStartElementAsync(null, "category", null);
+                        await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                        await xml.WriteStringAsync(genre.Name);
+                        await xml.WriteEndElementAsync(); // category
+                    }
+
+                    string artworkPath = GetPrioritizedArtworkPath(metadata);
+                    if (!string.IsNullOrWhiteSpace(artworkPath))
+                    {
+                        await xml.WriteStartElementAsync(null, "icon", null);
+                        await xml.WriteAttributeStringAsync(null, "src", null, artworkPath);
+                        await xml.WriteEndElementAsync(); // icon
+                    }
+                }
+
+                if (!isSameCustomShow)
+                {
+                    int s = await Optional(episode.Season?.SeasonNumber).IfNoneAsync(-1);
+                    // TODO: multi-episode?
+                    int e = episode.EpisodeMetadata.HeadOrNone().Match(em => em.EpisodeNumber, -1);
+                    if (s >= 0 && e > 0)
+                    {
+                        await xml.WriteStartElementAsync(null, "episode-num", null);
+                        await xml.WriteAttributeStringAsync(null, "system", null, "onscreen");
+                        await xml.WriteStringAsync($"S{s:00}E{e:00}");
+                        await xml.WriteEndElementAsync(); // episode-num
+
+                        await xml.WriteStartElementAsync(null, "episode-num", null);
+                        await xml.WriteAttributeStringAsync(null, "system", null, "xmltv_ns");
+                        await xml.WriteStringAsync($"{s - 1}.{e - 1}.0/1");
+                        await xml.WriteEndElementAsync(); // episode-num
+                    }
+                }
+            }
+
+            await xml.WriteStartElementAsync(null, "previously-shown", null);
+            await xml.WriteEndElementAsync(); // previously-shown
+
+            foreach (ContentRating rating in contentRating)
+            {
+                await xml.WriteStartElementAsync(null, "rating", null);
+                foreach (string system in rating.System)
+                {
+                    await xml.WriteAttributeStringAsync(null, "system", null, system);
+                }
+
+                await xml.WriteStartElementAsync(null, "value", null);
+                await xml.WriteStringAsync(rating.Value);
+                await xml.WriteEndElementAsync(); // value
+                await xml.WriteEndElementAsync(); // rating
+            }
+
+            await xml.WriteEndElementAsync(); // programme
+
+            i++;
+        }
+
+        await xml.FlushAsync();
+
+        string tempFile = Path.GetTempFileName();
+        await File.WriteAllBytesAsync(tempFile, ms.ToArray(), cancellationToken);
+
+        string targetFile = Path.Combine(FileSystemLayout.ChannelGuideCacheFolder, $"{request.ChannelNumber}.xml");
+        File.Move(tempFile, targetFile, true);
+    }
+    
+    private static string GetArtworkUrl(Artwork artwork, ArtworkKind artworkKind)
+    {
+        string artworkPath = artwork.Path;
+
+        int height = artworkKind switch
+        {
+            ArtworkKind.Thumbnail => 220,
+            _ => 440
+        };
+
+        if (artworkPath.StartsWith("jellyfin://"))
+        {
+            artworkPath = JellyfinUrl.PlaceholderProxyForArtwork(artworkPath, artworkKind, height);
+        }
+        else if (artworkPath.StartsWith("emby://"))
+        {
+            artworkPath = EmbyUrl.PlaceholderProxyForArtwork(artworkPath, artworkKind, height);
+        }
+        else
+        {
+            string artworkFolder = artworkKind switch
+            {
+                ArtworkKind.Thumbnail => "thumbnails",
+                _ => "posters"
+            };
+
+            artworkPath = $"{{RequestBase}}/iptv/artwork/{artworkFolder}/{artwork.Path}.jpg{{AccessTokenUri}}";
+        }
+
+        return artworkPath;
+    }
+
+    private static string GetTitle(PlayoutItem playoutItem)
+    {
+        if (!string.IsNullOrWhiteSpace(playoutItem.CustomTitle))
+        {
+            return playoutItem.CustomTitle;
+        }
+
+        return playoutItem.MediaItem switch
+        {
+            Movie m => m.MovieMetadata.HeadOrNone().Map(mm => mm.Title ?? string.Empty)
+                .IfNone("[unknown movie]"),
+            Episode e => e.Season.Show.ShowMetadata.HeadOrNone().Map(em => em.Title ?? string.Empty)
+                .IfNone("[unknown show]"),
+            MusicVideo mv => mv.Artist.ArtistMetadata.HeadOrNone().Map(am => am.Title ?? string.Empty)
+                .IfNone("[unknown artist]"),
+            OtherVideo ov => ov.OtherVideoMetadata.HeadOrNone().Map(vm => vm.Title ?? string.Empty)
+                .IfNone("[unknown video]"),
+            Song s => s.SongMetadata.HeadOrNone().Map(sm => sm.Artist ?? string.Empty)
+                .IfNone("[unknown artist]"),
+            _ => "[unknown]"
+        };
+    }
+
+    private static string GetSubtitle(PlayoutItem playoutItem)
+    {
+        if (!string.IsNullOrWhiteSpace(playoutItem.CustomTitle))
+        {
+            return string.Empty;
+        }
+
+        return playoutItem.MediaItem switch
+        {
+            Episode e => e.EpisodeMetadata.HeadOrNone().Match(
+                em => em.Title ?? string.Empty,
+                () => string.Empty),
+            MusicVideo mv => mv.MusicVideoMetadata.HeadOrNone().Match(
+                mvm => mvm.Title ?? string.Empty,
+                () => string.Empty),
+            Song s => s.SongMetadata.HeadOrNone().Match(
+                mvm => mvm.Title ?? string.Empty,
+                () => string.Empty),
+            _ => string.Empty
+        };
+    }
+
+    private static string GetDescription(PlayoutItem playoutItem)
+    {
+        if (!string.IsNullOrWhiteSpace(playoutItem.CustomTitle))
+        {
+            return string.Empty;
+        }
+
+        return playoutItem.MediaItem switch
+        {
+            Movie m => m.MovieMetadata.HeadOrNone().Map(mm => mm.Plot ?? string.Empty).IfNone(string.Empty),
+            Episode e => e.EpisodeMetadata.HeadOrNone().Map(em => em.Plot ?? string.Empty)
+                .IfNone(string.Empty),
+            MusicVideo mv => mv.MusicVideoMetadata.HeadOrNone().Map(mvm => mvm.Plot ?? string.Empty)
+                .IfNone(string.Empty),
+            OtherVideo ov => ov.OtherVideoMetadata.HeadOrNone().Map(ovm => ovm.Plot ?? string.Empty)
+                .IfNone(string.Empty),
+            _ => string.Empty
+        };
+    }
+    
+    private Option<ContentRating> GetContentRating(PlayoutItem playoutItem)
+    {
+        try
+        {
+            return playoutItem.MediaItem switch
+            {
+                Movie m => m.MovieMetadata
+                    .HeadOrNone()
+                    .Match(mm => ParseContentRating(mm.ContentRating, "MPAA"), () => None),
+                Episode e => e.Season.Show.ShowMetadata
+                    .HeadOrNone()
+                    .Match(sm => ParseContentRating(sm.ContentRating, "VCHIP"), () => None),
+                _ => None
+            };
+        }
+        catch (Exception ex)
+        {
+            _logger.LogWarning(ex, "Failed to get content rating for playout item {Item}", GetTitle(playoutItem));
+            return None;
+        }
+    }
+    
+    private static Option<ContentRating> ParseContentRating(string contentRating, string system)
+    {
+        Option<string> maybeFirst = (contentRating ?? string.Empty).Split('/').HeadOrNone();
+        return maybeFirst.Map(
+            first =>
+            {
+                string[] split = first.Split(':');
+                if (split.Length == 2)
+                {
+                    return split[0].ToLowerInvariant() == "us"
+                        ? new ContentRating(system, split[1].ToUpperInvariant())
+                        : new ContentRating(None, split[1].ToUpperInvariant());
+                }
+
+                return string.IsNullOrWhiteSpace(first)
+                    ? Option<ContentRating>.None
+                    : new ContentRating(None, first);
+            }).Flatten();
+    }
+
+    private record ContentRating(Option<string> System, string Value);
+    
+    private string GetPrioritizedArtworkPath(Metadata metadata)
+    {
+        Option<string> maybeArtwork = Optional(metadata.Artwork).Flatten()
+            .Filter(a => a.ArtworkKind == ArtworkKind.Poster)
+            .HeadOrNone()
+            .Map(a => GetArtworkUrl(a, ArtworkKind.Poster));
+
+        if (maybeArtwork.IsNone)
+        {
+            maybeArtwork = Optional(metadata.Artwork).Flatten()
+                .Filter(a => a.ArtworkKind == ArtworkKind.Thumbnail)
+                .HeadOrNone()
+                .Map(a => GetArtworkUrl(a, ArtworkKind.Thumbnail));
+        }
+
+        return maybeArtwork.IfNone(string.Empty);
+    }
+}
@@ -0,0 +1,3 @@
+namespace ErsatzTV.Application.Channels;
+
+public record RefreshChannelList : IRequest, IBackgroundServiceRequest;
@@ -0,0 +1,113 @@
+using System.Data;
+using System.Data.Common;
+using System.Xml;
+using Dapper;
+using ErsatzTV.Core;
+using ErsatzTV.Core.Interfaces.Metadata;
+using ErsatzTV.Infrastructure.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.IO;
+
+namespace ErsatzTV.Application.Channels;
+
+public class RefreshChannelListHandler : IRequestHandler<RefreshChannelList>
+{
+    private readonly RecyclableMemoryStreamManager _recyclableMemoryStreamManager;
+    private readonly IDbContextFactory<TvContext> _dbContextFactory;
+    private readonly ILocalFileSystem _localFileSystem;
+
+    public RefreshChannelListHandler(
+        RecyclableMemoryStreamManager recyclableMemoryStreamManager,
+        IDbContextFactory<TvContext> dbContextFactory,
+        ILocalFileSystem localFileSystem)
+    {
+        _recyclableMemoryStreamManager = recyclableMemoryStreamManager;
+        _dbContextFactory = dbContextFactory;
+        _localFileSystem = localFileSystem;
+    }
+
+    public async Task Handle(RefreshChannelList request, CancellationToken cancellationToken)
+    {
+        _localFileSystem.EnsureFolderExists(FileSystemLayout.ChannelGuideCacheFolder);
+        
+        await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
+
+        using MemoryStream ms = _recyclableMemoryStreamManager.GetStream();
+        await using var xml = XmlWriter.Create(
+            ms,
+            new XmlWriterSettings { Async = true, ConformanceLevel = ConformanceLevel.Fragment });
+
+        await foreach (ChannelResult channel in GetChannels(dbContext).WithCancellation(cancellationToken))
+        {
+            await xml.WriteStartElementAsync(null, "channel", null);
+            await xml.WriteAttributeStringAsync(null, "id", null, $"{channel.Number}.etv");
+
+            await xml.WriteStartElementAsync(null, "display-name", null);
+            await xml.WriteStringAsync($"{channel.Number} {channel.Name}");
+            await xml.WriteEndElementAsync(); // display-name (number and name)
+
+            await xml.WriteStartElementAsync(null, "display-name", null);
+            await xml.WriteStringAsync(channel.Number);
+            await xml.WriteEndElementAsync(); // display-name (number)
+
+            await xml.WriteStartElementAsync(null, "display-name", null);
+            await xml.WriteStringAsync(channel.Name);
+            await xml.WriteEndElementAsync(); // display-name (name)
+
+            foreach (string category in GetCategories(channel.Categories))
+            {
+                await xml.WriteStartElementAsync(null, "category", null);
+                await xml.WriteAttributeStringAsync(null, "lang", null, "en");
+                await xml.WriteStringAsync(category);
+                await xml.WriteEndElementAsync(); // category
+            }
+
+            await xml.WriteStartElementAsync(null, "icon", null);
+            await xml.WriteAttributeStringAsync(null, "src", null, GetIconUrl(channel));
+            await xml.WriteEndElementAsync(); // icon
+
+            await xml.WriteEndElementAsync(); // channel
+        }
+
+        await xml.FlushAsync();
+
+        string tempFile = Path.GetTempFileName();
+        await File.WriteAllBytesAsync(tempFile, ms.ToArray(), cancellationToken);
+        
+        string targetFile = Path.Combine(FileSystemLayout.ChannelGuideCacheFolder, "channels.xml");
+        File.Move(tempFile, targetFile, true);
+    }
+
+    private static async IAsyncEnumerable<ChannelResult> GetChannels(TvContext dbContext)
+    {
+        const string QUERY = @"select C.Number, C.Name, C.Categories, A.Path as ArtworkPath
+                               from Channel C
+                               left outer join Artwork A on C.Id = A.ChannelId and A.ArtworkKind = 2
+                               where C.Id in (select ChannelId from Playout)
+                               order by CAST(C.Number as real)";
+
+        await using var reader = (DbDataReader)await dbContext.Connection.ExecuteReaderAsync(QUERY);
+        Func<IDataReader, ChannelResult> rowParser = reader.GetRowParser<ChannelResult>();
+
+        while (await reader.ReadAsync()) {
+            yield return rowParser(reader);
+        }
+        
+        while (await reader.NextResultAsync()) {}
+    }
+        
+    private static List<string> GetCategories(string categories) =>
+        (categories ?? string.Empty).Split(',')
+        .Map(s => s.Trim())
+        .Filter(s => !string.IsNullOrWhiteSpace(s))
+        .Distinct()
+        .ToList();
+
+    private static string GetIconUrl(ChannelResult channel) =>
+        string.IsNullOrWhiteSpace(channel.ArtworkPath)
+            ? "{RequestBase}/iptv/images/ersatztv-500.png{AccessTokenUri}"
+            : $"{{RequestBase}}/iptv/logos/{channel.ArtworkPath}.jpg{{AccessTokenUri}}";
+
+    // ReSharper disable once ClassNeverInstantiated.Local
+    private record ChannelResult(string Number, string Name, string Categories, string ArtworkPath);
+}
@@ -1,5 +1,7 @@
+using ErsatzTV.Core;
 using ErsatzTV.Core.Iptv;

 namespace ErsatzTV.Application.Channels;

-public record GetChannelGuide(string Scheme, string Host, string BaseUrl, string AccessToken) : IRequest<ChannelGuide>;
+public record GetChannelGuide
+    (string Scheme, string Host, string BaseUrl, string AccessToken) : IRequest<Either<BaseError, ChannelGuide>>;
@@ -1,30 +1,72 @@
-using ErsatzTV.Core.Interfaces.Repositories;
+using System.Text;
+using ErsatzTV.Core;
+using ErsatzTV.Core.Interfaces.Metadata;
 using ErsatzTV.Core.Iptv;
+using ErsatzTV.Infrastructure.Data;
+using Microsoft.EntityFrameworkCore;
 using Microsoft.IO;

 namespace ErsatzTV.Application.Channels;

-public class GetChannelGuideHandler : IRequestHandler<GetChannelGuide, ChannelGuide>
+public class GetChannelGuideHandler : IRequestHandler<GetChannelGuide, Either<BaseError, ChannelGuide>>
 {
-    private readonly IChannelRepository _channelRepository;
+    private readonly IDbContextFactory<TvContext> _dbContextFactory;
    private readonly RecyclableMemoryStreamManager _recyclableMemoryStreamManager;
+    private readonly ILocalFileSystem _localFileSystem;

    public GetChannelGuideHandler(
-        IChannelRepository channelRepository,
-        RecyclableMemoryStreamManager recyclableMemoryStreamManager)
+        IDbContextFactory<TvContext> dbContextFactory,
+        RecyclableMemoryStreamManager recyclableMemoryStreamManager,
+        ILocalFileSystem localFileSystem)
    {
-        _channelRepository = channelRepository;
+        _dbContextFactory = dbContextFactory;
        _recyclableMemoryStreamManager = recyclableMemoryStreamManager;
+        _localFileSystem = localFileSystem;
    }

-    public Task<ChannelGuide> Handle(GetChannelGuide request, CancellationToken cancellationToken) =>
-        _channelRepository.GetAllForGuide()
-            .Map(
-                channels => new ChannelGuide(
-                    _recyclableMemoryStreamManager,
-                    request.Scheme,
-                    request.Host,
-                    request.BaseUrl,
-                    channels,
-                    request.AccessToken));
+    public async Task<Either<BaseError, ChannelGuide>> Handle(
+        GetChannelGuide request,
+        CancellationToken cancellationToken)
+    {
+        await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
+
+        string channelsFile = Path.Combine(FileSystemLayout.ChannelGuideCacheFolder, "channels.xml");
+        if (!_localFileSystem.FileExists(channelsFile))
+        {
+            return BaseError.New($"Required file {channelsFile} is missing");
+        }
+        
+        string accessTokenUri = string.Empty;
+        if (!string.IsNullOrWhiteSpace(request.AccessToken))
+        {
+            accessTokenUri = $"?access_token={request.AccessToken}";
+        }
+
+        string channelsFragment = await File.ReadAllTextAsync(channelsFile, Encoding.UTF8, cancellationToken);
+        
+        // TODO: is regex faster?
+        channelsFragment = channelsFragment
+            .Replace("{RequestBase}", $"{request.Scheme}://{request.Host}{request.BaseUrl}")
+            .Replace("{AccessTokenUri}", accessTokenUri);
+
+        var channelDataFragments = new Dictionary<string, string>();
+
+        foreach (string fileName in _localFileSystem.ListFiles(FileSystemLayout.ChannelGuideCacheFolder))
+        {
+            if (fileName.Contains("channels"))
+            {
+                continue;
+            }
+
+            string channelDataFragment = await File.ReadAllTextAsync(fileName, Encoding.UTF8, cancellationToken);
+            
+            channelDataFragment = channelDataFragment
+                .Replace("{RequestBase}", $"{request.Scheme}://{request.Host}{request.BaseUrl}")
+                .Replace("{AccessTokenUri}", accessTokenUri);
+
+            channelDataFragments.Add(Path.GetFileNameWithoutExtension(fileName), channelDataFragment);
+        }
+
+        return new ChannelGuide(_recyclableMemoryStreamManager, channelsFragment, channelDataFragments);
+    }
 }
@@ -1,5 +1,7 @@
 using System.Threading.Channels;
 using Bugsnag;
+using Dapper;
+using ErsatzTV.Application.Channels;
 using ErsatzTV.Application.Subtitles;
 using ErsatzTV.Core;
 using ErsatzTV.Core.Domain;
@@ -56,6 +58,23 @@ public class BuildPlayoutHandler : IRequestHandler<BuildPlayout, Either<BaseErro
                _ffmpegSegmenterService.PlayoutUpdated(playout.Channel.Number);
            }

+            Option<string> maybeChannelNumber = await dbContext.Connection
+                .QuerySingleOrDefaultAsync<string>(
+                    @"select C.Number from Channel C
+                         inner join Playout P on C.Id = P.ChannelId
+                         where P.Id = @PlayoutId",
+                    new { request.PlayoutId })
+                .Map(Optional);
+
+            foreach (string channelNumber in maybeChannelNumber)
+            {
+                string fileName = Path.Combine(FileSystemLayout.ChannelGuideCacheFolder, $"{channelNumber}.xml");
+                if (hasChanges || !File.Exists(fileName))
+                {
+                    await _workerChannel.WriteAsync(new RefreshChannelData(channelNumber));
+                }
+            }
+
            await _workerChannel.WriteAsync(new ExtractEmbeddedSubtitles(playout.Id));
        }
        catch (Exception ex)
@@ -1,4 +1,5 @@
 using System.Threading.Channels;
+using ErsatzTV.Application.Channels;
 using ErsatzTV.Core;
 using ErsatzTV.Core.Domain;
 using ErsatzTV.Core.Scheduling;
@@ -28,7 +29,7 @@ public class CreatePlayoutHandler : IRequestHandler<CreatePlayout, Either<BaseEr
    {
        await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
        Validation<BaseError, Playout> validation = await Validate(dbContext, request);
-        return await LanguageExtensions.Apply(validation, playout => PersistPlayout(dbContext, playout));
+        return await validation.Apply(playout => PersistPlayout(dbContext, playout));
    }

    private async Task<CreatePlayoutResponse> PersistPlayout(TvContext dbContext, Playout playout)
@@ -36,6 +37,7 @@ public class CreatePlayoutHandler : IRequestHandler<CreatePlayout, Either<BaseEr
        await dbContext.Playouts.AddAsync(playout);
        await dbContext.SaveChangesAsync();
        await _channel.WriteAsync(new BuildPlayout(playout.Id, PlayoutBuildMode.Reset));
+        await _channel.WriteAsync(new RefreshChannelList());
        return new CreatePlayoutResponse(playout.Id);
    }

@@ -1,31 +1,55 @@
-using ErsatzTV.Core;
+using System.Threading.Channels;
+using ErsatzTV.Application.Channels;
+using ErsatzTV.Core;
 using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Interfaces.Metadata;
 using ErsatzTV.Infrastructure.Data;
+using ErsatzTV.Infrastructure.Extensions;
 using Microsoft.EntityFrameworkCore;

 namespace ErsatzTV.Application.Playouts;

 public class DeletePlayoutHandler : IRequestHandler<DeletePlayout, Either<BaseError, Unit>>
 {
+    private readonly ChannelWriter<IBackgroundServiceRequest> _workerChannel;
    private readonly IDbContextFactory<TvContext> _dbContextFactory;
+    private readonly ILocalFileSystem _localFileSystem;

-    public DeletePlayoutHandler(IDbContextFactory<TvContext> dbContextFactory) =>
+    public DeletePlayoutHandler(
+        ChannelWriter<IBackgroundServiceRequest> workerChannel,
+        IDbContextFactory<TvContext> dbContextFactory,
+        ILocalFileSystem localFileSystem)
+    {
+        _workerChannel = workerChannel;
        _dbContextFactory = dbContextFactory;
+        _localFileSystem = localFileSystem;
+    }

    public async Task<Either<BaseError, Unit>> Handle(
        DeletePlayout request,
        CancellationToken cancellationToken)
    {
-        await using TvContext dbContext = _dbContextFactory.CreateDbContext();
+        await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);

        Option<Playout> maybePlayout = await dbContext.Playouts
-            .OrderBy(p => p.Id)
-            .FirstOrDefaultAsync(p => p.Id == request.PlayoutId, cancellationToken);
+            .AsNoTracking()
+            .Include(p => p.Channel)
+            .SelectOneAsync(p => p.Id, p => p.Id == request.PlayoutId);

        foreach (Playout playout in maybePlayout)
        {
            dbContext.Playouts.Remove(playout);
            await dbContext.SaveChangesAsync(cancellationToken);
+
+            // delete channel data from channel guide cache
+            string cacheFile = Path.Combine(FileSystemLayout.ChannelGuideCacheFolder, $"{playout.Channel.Number}.xml");
+            if (_localFileSystem.FileExists(cacheFile))
+            {
+                File.Delete(cacheFile);
+            }
+
+            // refresh channel list to remove channel that has no playout
+            await _workerChannel.WriteAsync(new RefreshChannelList(), cancellationToken);
        }

        return maybePlayout
@@ -40,8 +40,8 @@ public static class EmbyUrl
            .AppendPathSegment(pathSegment)
            .SetQueryParams(query);
    }
-
-    public static Url ProxyForArtwork(string scheme, string host, string artwork, ArtworkKind artworkKind)
+    
+    public static string PlaceholderProxyForArtwork(string artwork, ArtworkKind artworkKind, int height)
    {
        string[] split = artwork.Replace("emby://", string.Empty).Split('?');
        if (split.Length != 2)
@@ -58,9 +58,12 @@ public static class EmbyUrl
            _ => "posters"
        };

-        return Url.Parse($"{scheme}://{host}/iptv/artwork/{artworkFolder}/emby")
+        return Url.Parse($"http://not-a-real-host/iptv/artwork/{artworkFolder}/emby")
            .AppendPathSegment(pathSegment)
-            .SetQueryParams(query);
+            .SetQueryParams(query)
+            .SetQueryParam("maxHeight", height)
+            .ToString()
+            .Replace("http://not-a-real-host", "{RequestBase}");
    }

    public static Url RelativeProxyForArtwork(string artwork)
@@ -23,6 +23,7 @@ public static class FileSystemLayout

    public static readonly string LegacyImageCacheFolder = Path.Combine(AppDataFolder, "cache", "images");
    public static readonly string ResourcesCacheFolder = Path.Combine(AppDataFolder, "cache", "resources");
+    public static readonly string ChannelGuideCacheFolder = Path.Combine(AppDataFolder, "cache", "channel-guide");

    public static readonly string PlexSecretsPath = Path.Combine(AppDataFolder, "plex-secrets.json");
    public static readonly string JellyfinSecretsPath = Path.Combine(AppDataFolder, "jellyfin-secrets.json");
@@ -1,42 +1,23 @@
 using System.Text;
 using System.Xml;
-using ErsatzTV.Core.Domain;
-using ErsatzTV.Core.Domain.Filler;
-using ErsatzTV.Core.Emby;
-using ErsatzTV.Core.Jellyfin;
 using Microsoft.IO;
-using Serilog;

 namespace ErsatzTV.Core.Iptv;

 public class ChannelGuide
 {
-    private readonly List<Channel> _channels;
-    private readonly string _host;
-    private readonly string _baseUrl;
+    private readonly string _channelsFragment;
+    private readonly Dictionary<string, string> _channelDataFragments;
    private readonly RecyclableMemoryStreamManager _recyclableMemoryStreamManager;
-    private readonly string _scheme;
-    private readonly string _accessTokenUri;

    public ChannelGuide(
        RecyclableMemoryStreamManager recyclableMemoryStreamManager,
-        string scheme,
-        string host,
-        string baseUrl,
-        List<Channel> channels,
-        string accessToken)
+        string channelsFragment,
+        Dictionary<string, string> channelDataFragments)
    {
        _recyclableMemoryStreamManager = recyclableMemoryStreamManager;
-        _scheme = scheme;
-        _host = host;
-        _baseUrl = baseUrl;
-        _channels = channels;
-        
-        _accessTokenUri = string.Empty;
-        if (!string.IsNullOrWhiteSpace(accessToken))
-        {
-            _accessTokenUri = $"?access_token={accessToken}";
-        }
+        _channelsFragment = channelsFragment;
+        _channelDataFragments = channelDataFragments;
    }

    public string ToXml()
@@ -47,314 +28,13 @@ public class ChannelGuide

        xml.WriteStartElement("tv");
        xml.WriteAttributeString("generator-info-name", "ersatztv");
+        
+        xml.WriteRaw(_channelsFragment);

-        var sortedChannelItems = new Dictionary<Channel, List<PlayoutItem>>();
-
-        foreach (Channel channel in _channels.OrderBy(c => decimal.Parse(c.Number)))
+        foreach ((string channelNumber, string channelDataFragment) in _channelDataFragments.OrderBy(
+                     kvp => decimal.Parse(kvp.Key)))
        {
-            var sortedItems = channel.Playouts.Collect(p => p.Items).OrderBy(x => x.Start).ToList();
-            sortedChannelItems.Add(channel, sortedItems);
-
-            if (sortedItems.Any())
-            {
-                xml.WriteStartElement("channel");
-                xml.WriteAttributeString("id", $"{channel.Number}.etv");
-
-                xml.WriteStartElement("display-name");
-                xml.WriteString($"{channel.Number} {channel.Name}");
-                xml.WriteEndElement(); // display-name (number and name)
-
-                xml.WriteStartElement("display-name");
-                xml.WriteString(channel.Number);
-                xml.WriteEndElement(); // display-name (number)
-
-                xml.WriteStartElement("display-name");
-                xml.WriteString(channel.Name);
-                xml.WriteEndElement(); // display-name (name)
-
-                foreach (string category in GetCategories(channel.Categories))
-                {
-                    xml.WriteStartElement("category");
-                    xml.WriteAttributeString("lang", "en");
-                    xml.WriteString(category);
-                    xml.WriteEndElement(); // category
-                }
-
-                xml.WriteStartElement("icon");
-                string logo = Optional(channel.Artwork).Flatten()
-                    .Filter(a => a.ArtworkKind == ArtworkKind.Logo)
-                    .HeadOrNone()
-                    .Match(
-                        artwork => $"{_scheme}://{_host}{_baseUrl}/iptv/logos/{artwork.Path}.jpg{_accessTokenUri}",
-                        () => $"{_scheme}://{_host}{_baseUrl}/iptv/images/ersatztv-500.png{_accessTokenUri}");
-                xml.WriteAttributeString("src", logo);
-                xml.WriteEndElement(); // icon
-
-                xml.WriteEndElement(); // channel
-            }
-        }
-
-        foreach ((Channel channel, List<PlayoutItem> sorted) in sortedChannelItems.OrderBy(
-                     kvp => decimal.Parse(kvp.Key.Number)))
-        {
-            // skip all filler that isn't pre-roll
-            var i = 0;
-            while (i < sorted.Count && sorted[i].FillerKind != FillerKind.None &&
-                   sorted[i].FillerKind != FillerKind.PreRoll)
-            {
-                i++;
-            }
-
-            while (i < sorted.Count)
-            {
-                PlayoutItem startItem = sorted[i];
-                int j = i;
-                while (sorted[j].FillerKind != FillerKind.None && j + 1 < sorted.Count)
-                {
-                    j++;
-                }
-
-                PlayoutItem displayItem = sorted[j];
-                bool hasCustomTitle = !string.IsNullOrWhiteSpace(startItem.CustomTitle);
-
-                int finishIndex = j;
-                while (finishIndex + 1 < sorted.Count && (sorted[finishIndex + 1].GuideGroup == startItem.GuideGroup
-                                                          || sorted[finishIndex + 1].FillerKind is FillerKind.GuideMode
-                                                              or FillerKind.Tail or FillerKind.Fallback))
-                {
-                    finishIndex++;
-                }
-
-                int customShowId = -1;
-                if (displayItem.MediaItem is Episode ep)
-                {
-                    customShowId = ep.Season.ShowId;
-                }
-
-                bool isSameCustomShow = hasCustomTitle;
-                for (int x = j; x <= finishIndex; x++)
-                {
-                    isSameCustomShow = isSameCustomShow && sorted[x].MediaItem is Episode e &&
-                                       customShowId == e.Season.ShowId;
-                }
-
-                PlayoutItem finishItem = sorted[finishIndex];
-                i = finishIndex;
-
-                string start = startItem.StartOffset.ToString("yyyyMMddHHmmss zzz").Replace(":", string.Empty);
-                string stop = displayItem.GuideFinishOffset.HasValue
-                    ? displayItem.GuideFinishOffset.Value.ToString("yyyyMMddHHmmss zzz").Replace(":", string.Empty)
-                    : finishItem.FinishOffset.ToString("yyyyMMddHHmmss zzz").Replace(":", string.Empty);
-
-                string title = GetTitle(displayItem);
-                string subtitle = GetSubtitle(displayItem);
-                string description = GetDescription(displayItem);
-                Option<ContentRating> contentRating = GetContentRating(displayItem);
-
-                xml.WriteStartElement("programme");
-                xml.WriteAttributeString("start", start);
-                xml.WriteAttributeString("stop", stop);
-                xml.WriteAttributeString("channel", $"{channel.Number}.etv");
-
-                xml.WriteStartElement("title");
-                xml.WriteAttributeString("lang", "en");
-                xml.WriteString(title);
-                xml.WriteEndElement(); // title
-
-                if (!string.IsNullOrWhiteSpace(subtitle))
-                {
-                    xml.WriteStartElement("sub-title");
-                    xml.WriteAttributeString("lang", "en");
-                    xml.WriteString(subtitle);
-                    xml.WriteEndElement(); // subtitle
-                }
-
-                if (!isSameCustomShow)
-                {
-                    if (!string.IsNullOrWhiteSpace(description))
-                    {
-                        xml.WriteStartElement("desc");
-                        xml.WriteAttributeString("lang", "en");
-                        xml.WriteString(description);
-                        xml.WriteEndElement(); // desc
-                    }
-                }
-
-                if (!hasCustomTitle && displayItem.MediaItem is Movie movie)
-                {
-                    foreach (MovieMetadata metadata in movie.MovieMetadata.HeadOrNone())
-                    {
-                        if (metadata.Year.HasValue)
-                        {
-                            xml.WriteStartElement("date");
-                            xml.WriteString(metadata.Year.Value.ToString());
-                            xml.WriteEndElement(); // date
-                        }
-
-                        xml.WriteStartElement("category");
-                        xml.WriteAttributeString("lang", "en");
-                        xml.WriteString("Movie");
-                        xml.WriteEndElement(); // category
-
-                        foreach (Genre genre in Optional(metadata.Genres).Flatten())
-                        {
-                            xml.WriteStartElement("category");
-                            xml.WriteAttributeString("lang", "en");
-                            xml.WriteString(genre.Name);
-                            xml.WriteEndElement(); // category
-                        }
-
-                        string poster = Optional(metadata.Artwork).Flatten()
-                            .Filter(a => a.ArtworkKind == ArtworkKind.Poster)
-                            .HeadOrNone()
-                            .Match(a => GetArtworkUrl(a, ArtworkKind.Poster), () => string.Empty);
-
-                        if (!string.IsNullOrWhiteSpace(poster))
-                        {
-                            xml.WriteStartElement("icon");
-                            xml.WriteAttributeString("src", poster);
-                            xml.WriteEndElement(); // icon
-                        }
-                    }
-                }
-
-                if (!hasCustomTitle && displayItem.MediaItem is MusicVideo musicVideo)
-                {
-                    foreach (MusicVideoMetadata metadata in musicVideo.MusicVideoMetadata.HeadOrNone())
-                    {
-                        if (metadata.Year.HasValue)
-                        {
-                            xml.WriteStartElement("date");
-                            xml.WriteString(metadata.Year.Value.ToString());
-                            xml.WriteEndElement(); // date
-                        }
-
-                        xml.WriteStartElement("category");
-                        xml.WriteAttributeString("lang", "en");
-                        xml.WriteString("Music");
-                        xml.WriteEndElement(); // category
-
-                        // music video genres
-                        foreach (Genre genre in Optional(metadata.Genres).Flatten())
-                        {
-                            xml.WriteStartElement("category");
-                            xml.WriteAttributeString("lang", "en");
-                            xml.WriteString(genre.Name);
-                            xml.WriteEndElement(); // category
-                        }
-
-                        // artist genres
-                        Option<ArtistMetadata> maybeMetadata =
-                            Optional(musicVideo.Artist?.ArtistMetadata.HeadOrNone()).Flatten();
-                        foreach (ArtistMetadata artistMetadata in maybeMetadata)
-                        {
-                            foreach (Genre genre in Optional(artistMetadata.Genres).Flatten())
-                            {
-                                xml.WriteStartElement("category");
-                                xml.WriteAttributeString("lang", "en");
-                                xml.WriteString(genre.Name);
-                                xml.WriteEndElement(); // category
-                            }
-                        }
-
-                        string artworkPath = GetPrioritizedArtworkPath(metadata);
-                        if (!string.IsNullOrWhiteSpace(artworkPath))
-                        {
-                            xml.WriteStartElement("icon");
-                            xml.WriteAttributeString("src", artworkPath);
-                            xml.WriteEndElement(); // icon
-                        }
-                    }
-                }
-
-                if (!hasCustomTitle && displayItem.MediaItem is Song song)
-                {
-                    xml.WriteStartElement("category");
-                    xml.WriteAttributeString("lang", "en");
-                    xml.WriteString("Music");
-                    xml.WriteEndElement(); // category
-
-                    foreach (SongMetadata metadata in song.SongMetadata.HeadOrNone())
-                    {
-                        string artworkPath = GetPrioritizedArtworkPath(metadata);
-                        if (!string.IsNullOrWhiteSpace(artworkPath))
-                        {
-                            xml.WriteStartElement("icon");
-                            xml.WriteAttributeString("src", artworkPath);
-                            xml.WriteEndElement(); // icon
-                        }
-                    }
-                }
-
-                if (displayItem.MediaItem is Episode episode && (!hasCustomTitle || isSameCustomShow))
-                {
-                    Option<ShowMetadata> maybeMetadata =
-                        Optional(episode.Season?.Show?.ShowMetadata.HeadOrNone()).Flatten();
-                    foreach (ShowMetadata metadata in maybeMetadata)
-                    {
-                        xml.WriteStartElement("category");
-                        xml.WriteAttributeString("lang", "en");
-                        xml.WriteString("Series");
-                        xml.WriteEndElement(); // category
-
-                        foreach (Genre genre in Optional(metadata.Genres).Flatten())
-                        {
-                            xml.WriteStartElement("category");
-                            xml.WriteAttributeString("lang", "en");
-                            xml.WriteString(genre.Name);
-                            xml.WriteEndElement(); // category
-                        }
-
-                        string artworkPath = GetPrioritizedArtworkPath(metadata);
-                        if (!string.IsNullOrWhiteSpace(artworkPath))
-                        {
-                            xml.WriteStartElement("icon");
-                            xml.WriteAttributeString("src", artworkPath);
-                            xml.WriteEndElement(); // icon
-                        }
-                    }
-
-                    if (!isSameCustomShow)
-                    {
-                        int s = Optional(episode.Season?.SeasonNumber).IfNone(-1);
-                        // TODO: multi-episode?
-                        int e = episode.EpisodeMetadata.HeadOrNone().Match(em => em.EpisodeNumber, -1);
-                        if (s >= 0 && e > 0)
-                        {
-                            xml.WriteStartElement("episode-num");
-                            xml.WriteAttributeString("system", "onscreen");
-                            xml.WriteString($"S{s:00}E{e:00}");
-                            xml.WriteEndElement(); // episode-num
-
-                            xml.WriteStartElement("episode-num");
-                            xml.WriteAttributeString("system", "xmltv_ns");
-                            xml.WriteString($"{s - 1}.{e - 1}.0/1");
-                            xml.WriteEndElement(); // episode-num
-                        }
-                    }
-                }
-
-                xml.WriteStartElement("previously-shown");
-                xml.WriteEndElement(); // previously-shown
-
-                foreach (ContentRating rating in contentRating)
-                {
-                    xml.WriteStartElement("rating");
-                    foreach (string system in rating.System)
-                    {
-                        xml.WriteAttributeString("system", system);
-                    }
-
-                    xml.WriteStartElement("value");
-                    xml.WriteString(rating.Value);
-                    xml.WriteEndElement(); // value
-                    xml.WriteEndElement(); // rating
-                }
-
-                xml.WriteEndElement(); // programme
-
-                i++;
-            }
+            xml.WriteRaw(channelDataFragment);
        }

        xml.WriteEndElement(); // tv
@@ -363,172 +43,4 @@ public class ChannelGuide
        xml.Flush();
        return Encoding.UTF8.GetString(ms.ToArray());
    }
-
-    private string GetArtworkUrl(Artwork artwork, ArtworkKind artworkKind)
-    {
-        string artworkPath = artwork.Path;
-
-        int height = artworkKind switch
-        {
-            ArtworkKind.Thumbnail => 220,
-            _ => 440
-        };
-
-        if (artworkPath.StartsWith("jellyfin://"))
-        {
-            artworkPath = JellyfinUrl.ProxyForArtwork(_scheme, _host, artworkPath, artworkKind)
-                .SetQueryParam("fillHeight", height);
-        }
-        else if (artworkPath.StartsWith("emby://"))
-        {
-            artworkPath = EmbyUrl.ProxyForArtwork(_scheme, _host, artworkPath, artworkKind)
-                .SetQueryParam("maxHeight", height);
-        }
-        else
-        {
-            string artworkFolder = artworkKind switch
-            {
-                ArtworkKind.Thumbnail => "thumbnails",
-                _ => "posters"
-            };
-
-            artworkPath = $"{_scheme}://{_host}{_baseUrl}/iptv/artwork/{artworkFolder}/{artwork.Path}.jpg{_accessTokenUri}";
-        }
-
-        return artworkPath;
-    }
-
-    private static string GetTitle(PlayoutItem playoutItem)
-    {
-        if (!string.IsNullOrWhiteSpace(playoutItem.CustomTitle))
-        {
-            return playoutItem.CustomTitle;
-        }
-
-        return playoutItem.MediaItem switch
-        {
-            Movie m => m.MovieMetadata.HeadOrNone().Map(mm => mm.Title ?? string.Empty)
-                .IfNone("[unknown movie]"),
-            Episode e => e.Season.Show.ShowMetadata.HeadOrNone().Map(em => em.Title ?? string.Empty)
-                .IfNone("[unknown show]"),
-            MusicVideo mv => mv.Artist.ArtistMetadata.HeadOrNone().Map(am => am.Title ?? string.Empty)
-                .IfNone("[unknown artist]"),
-            OtherVideo ov => ov.OtherVideoMetadata.HeadOrNone().Map(vm => vm.Title ?? string.Empty)
-                .IfNone("[unknown video]"),
-            Song s => s.SongMetadata.HeadOrNone().Map(sm => sm.Artist ?? string.Empty)
-                .IfNone("[unknown artist]"),
-            _ => "[unknown]"
-        };
-    }
-
-    private static string GetSubtitle(PlayoutItem playoutItem)
-    {
-        if (!string.IsNullOrWhiteSpace(playoutItem.CustomTitle))
-        {
-            return string.Empty;
-        }
-
-        return playoutItem.MediaItem switch
-        {
-            Episode e => e.EpisodeMetadata.HeadOrNone().Match(
-                em => em.Title ?? string.Empty,
-                () => string.Empty),
-            MusicVideo mv => mv.MusicVideoMetadata.HeadOrNone().Match(
-                mvm => mvm.Title ?? string.Empty,
-                () => string.Empty),
-            Song s => s.SongMetadata.HeadOrNone().Match(
-                mvm => mvm.Title ?? string.Empty,
-                () => string.Empty),
-            _ => string.Empty
-        };
-    }
-
-    private static string GetDescription(PlayoutItem playoutItem)
-    {
-        if (!string.IsNullOrWhiteSpace(playoutItem.CustomTitle))
-        {
-            return string.Empty;
-        }
-
-        return playoutItem.MediaItem switch
-        {
-            Movie m => m.MovieMetadata.HeadOrNone().Map(mm => mm.Plot ?? string.Empty).IfNone(string.Empty),
-            Episode e => e.EpisodeMetadata.HeadOrNone().Map(em => em.Plot ?? string.Empty)
-                .IfNone(string.Empty),
-            MusicVideo mv => mv.MusicVideoMetadata.HeadOrNone().Map(mvm => mvm.Plot ?? string.Empty)
-                .IfNone(string.Empty),
-            OtherVideo ov => ov.OtherVideoMetadata.HeadOrNone().Map(ovm => ovm.Plot ?? string.Empty)
-                .IfNone(string.Empty),
-            _ => string.Empty
-        };
-    }
-
-    private static Option<ContentRating> GetContentRating(PlayoutItem playoutItem)
-    {
-        try
-        {
-            return playoutItem.MediaItem switch
-            {
-                Movie m => m.MovieMetadata
-                    .HeadOrNone()
-                    .Match(mm => ParseContentRating(mm.ContentRating, "MPAA"), () => None),
-                Episode e => e.Season.Show.ShowMetadata
-                    .HeadOrNone()
-                    .Match(sm => ParseContentRating(sm.ContentRating, "VCHIP"), () => None),
-                _ => None
-            };
-        }
-        catch (Exception ex)
-        {
-            Log.Logger.Warning(ex, "Failed to get content rating for playout item {Item}", GetTitle(playoutItem));
-            return None;
-        }
-    }
-
-    private static Option<ContentRating> ParseContentRating(string contentRating, string system)
-    {
-        Option<string> maybeFirst = (contentRating ?? string.Empty).Split('/').HeadOrNone();
-        return maybeFirst.Map(
-            first =>
-            {
-                string[] split = first.Split(':');
-                if (split.Length == 2)
-                {
-                    return split[0].ToLowerInvariant() == "us"
-                        ? new ContentRating(system, split[1].ToUpperInvariant())
-                        : new ContentRating(None, split[1].ToUpperInvariant());
-                }
-
-                return string.IsNullOrWhiteSpace(first)
-                    ? Option<ContentRating>.None
-                    : new ContentRating(None, first);
-            }).Flatten();
-    }
-
-    private static List<string> GetCategories(string categories) =>
-        (categories ?? string.Empty).Split(',')
-        .Map(s => s.Trim())
-        .Filter(s => !string.IsNullOrWhiteSpace(s))
-        .Distinct()
-        .ToList();
-
-    private record ContentRating(Option<string> System, string Value);
-
-    private string GetPrioritizedArtworkPath(Domain.Metadata metadata)
-    {
-        Option<string> maybeArtwork = Optional(metadata.Artwork).Flatten()
-            .Filter(a => a.ArtworkKind == ArtworkKind.Poster)
-            .HeadOrNone()
-            .Map(a => GetArtworkUrl(a, ArtworkKind.Poster));
-
-        if (maybeArtwork.IsNone)
-        {
-            maybeArtwork = Optional(metadata.Artwork).Flatten()
-                .Filter(a => a.ArtworkKind == ArtworkKind.Thumbnail)
-                .HeadOrNone()
-                .Map(a => GetArtworkUrl(a, ArtworkKind.Thumbnail));
-        }
-
-        return maybeArtwork.IfNone(string.Empty);
-    }
 }
@@ -41,6 +41,31 @@ public static class JellyfinUrl
            .SetQueryParams(query);
    }

+    public static string PlaceholderProxyForArtwork(string artwork, ArtworkKind artworkKind, int height)
+    {
+        string[] split = artwork.Replace("jellyfin://", string.Empty).Split('?');
+        if (split.Length != 2)
+        {
+            return artwork;
+        }
+
+        string pathSegment = split[0];
+        QueryParamCollection query = Url.ParseQueryParams(split[1]);
+
+        string artworkFolder = artworkKind switch
+        {
+            ArtworkKind.Thumbnail => "thumbnails",
+            _ => "posters"
+        };
+
+        return Url.Parse($"http://not-a-real-host/iptv/artwork/{artworkFolder}/jellyfin")
+            .AppendPathSegment(pathSegment)
+            .SetQueryParams(query)
+            .SetQueryParam("fillHeight", height)
+            .ToString()
+            .Replace("http://not-a-real-host", "{RequestBase}");
+    }
+
    public static Url ProxyForArtwork(string scheme, string host, string artwork, ArtworkKind artworkKind)
    {
        string[] split = artwork.Replace("jellyfin://", string.Empty).Split('?');
@@ -47,8 +47,9 @@ public class ChannelRepository : IChannelRepository

    public async Task<List<Channel>> GetAllForGuide()
    {
-        await using TvContext dbContext = _dbContextFactory.CreateDbContext();
+        await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync();
        return await dbContext.Channels
+            .AsNoTracking()
            .Include(c => c.Artwork)
            .Include(c => c.Playouts)
            .ThenInclude(p => p.Items)
@@ -9,6 +9,7 @@ using ErsatzTV.Core.Errors;
 using ErsatzTV.Core.FFmpeg;
 using ErsatzTV.Core.Interfaces.FFmpeg;
 using ErsatzTV.Core.Iptv;
+using ErsatzTV.Extensions;
 using ErsatzTV.Filters;
 using MediatR;
 using Microsoft.AspNetCore.Mvc;
@@ -55,7 +56,7 @@ public class IptvController : ControllerBase
                    Request.Host.ToString(),
                    Request.PathBase,
                    Request.Query["access_token"]))
-            .Map<ChannelGuide, IActionResult>(Ok);
+            .ToActionResult();

    [HttpGet("iptv/hdhr/channel/{channelNumber}.ts")]
    public Task<IActionResult> GetHDHRVideo(string channelNumber, [FromQuery] string mode = "ts")
@@ -1,6 +1,7 @@
 using System.Threading.Channels;
 using Bugsnag;
 using ErsatzTV.Application;
+using ErsatzTV.Application.Channels;
 using ErsatzTV.Application.Emby;
 using ErsatzTV.Application.Jellyfin;
 using ErsatzTV.Application.Maintenance;
@@ -91,6 +92,7 @@ public class SchedulerService : BackgroundService
        try
        {
            await DeleteOrphanedArtwork(cancellationToken);
+            await RefreshChannelGuideChannelList(cancellationToken);
            await BuildPlayouts(cancellationToken);
 #if !DEBUG_NO_SYNC
            await ScanLocalMediaSources(cancellationToken);
@@ -185,6 +187,9 @@ public class SchedulerService : BackgroundService
        }
    }

+    private ValueTask RefreshChannelGuideChannelList(CancellationToken cancellationToken) =>
+        _workerChannel.WriteAsync(new RefreshChannelList(), cancellationToken);
+
    private async Task ScanLocalMediaSources(CancellationToken cancellationToken)
    {
        using IServiceScope scope = _serviceScopeFactory.CreateScope();
@@ -1,6 +1,7 @@
 using System.Threading.Channels;
 using Bugsnag;
 using ErsatzTV.Application;
+using ErsatzTV.Application.Channels;
 using ErsatzTV.Application.Maintenance;
 using ErsatzTV.Application.MediaCollections;
 using ErsatzTV.Application.Playouts;
@@ -47,6 +48,12 @@ public class WorkerService : BackgroundService

                    switch (request)
                    {
+                        case RefreshChannelList refreshChannelList:
+                            await mediator.Send(refreshChannelList, cancellationToken);
+                            break;
+                        case RefreshChannelData refreshChannelData:
+                            await mediator.Send(refreshChannelData, cancellationToken);
+                            break;
                        case BuildPlayout buildPlayout:
                            Either<BaseError, Unit> buildPlayoutResult = await mediator.Send(
                                buildPlayout,