return multi variant playlist from start ffmpeg session

ErsatzTV.Application/Streaming/Commands/StartFFmpegSession.cs

@@ -2,6 +2,12 @@
 
 namespace ErsatzTV.Application.Streaming;
 
-public record StartFFmpegSession(string ChannelNumber, string Mode, string Scheme, string Host) :
+public record StartFFmpegSession(
-    IRequest<Either<BaseError, Unit>>,
+    string ChannelNumber,
+    string Mode,
+    string Scheme,
+    string Host,
+    string PathBase,
+    string AccessTokenQuery) :
+    IRequest<Either<BaseError, string>>,
     IFFmpegWorkerRequest;

ErsatzTV.Application/Streaming/Commands/StartFFmpegSessionHandler.cs

@@ -1,4 +1,5 @@
-using System.IO.Abstractions;
+using System.Globalization;
+using System.IO.Abstractions;
 using System.Threading.Channels;
 using ErsatzTV.Application.Channels;
 using ErsatzTV.Application.Graphics;
@@ -19,7 +20,7 @@ using Microsoft.Extensions.Logging;
 
 namespace ErsatzTV.Application.Streaming;
 
-public class StartFFmpegSessionHandler : IRequestHandler<StartFFmpegSession, Either<BaseError, Unit>>
+public class StartFFmpegSessionHandler : IRequestHandler<StartFFmpegSession, Either<BaseError, string>>
 {
     private readonly IFileSystem _fileSystem;
     private readonly IConfigElementRepository _configElementRepository;
@@ -65,15 +66,15 @@ public class StartFFmpegSessionHandler : IRequestHandler<StartFFmpegSession, Eit
         _workerChannel = workerChannel;
     }
 
-    public Task<Either<BaseError, Unit>> Handle(StartFFmpegSession request, CancellationToken cancellationToken) =>
+    public Task<Either<BaseError, string>> Handle(StartFFmpegSession request, CancellationToken cancellationToken) =>
         Validate(request)
             .MapT(_ => StartProcess(request, cancellationToken))
             // this weirdness is needed to maintain the error type (.ToEitherAsync() just gives BaseError)
 #pragma warning disable VSTHRD103
-            .Bind(v => v.ToEither().MapLeft(seq => seq.Head()).MapAsync<BaseError, Task<Unit>, Unit>(identity));
+            .Bind(v => v.ToEither().MapLeft(seq => seq.Head()).MapAsync<BaseError, Task<string>, string>(identity));
 #pragma warning restore VSTHRD103
 
-    private async Task<Unit> StartProcess(StartFFmpegSession request, CancellationToken cancellationToken)
+    private async Task<string> StartProcess(StartFFmpegSession request, CancellationToken cancellationToken)
     {
         Option<TimeSpan> idleTimeout = await _configElementRepository
             .GetValue<int>(ConfigElementKey.FFmpegSegmenterTimeout, cancellationToken)
@@ -116,7 +117,7 @@ public class StartFFmpegSessionHandler : IRequestHandler<StartFFmpegSession, Eit
 
         await worker.WaitForPlaylistSegments(initialSegmentCount, cancellationToken);
 
-        return Unit.Default;
+        return await GetMultiVariantPlaylist(request);
     }
 
     private HlsSessionWorker GetSessionWorker(StartFFmpegSession request, Option<FrameRate> targetFramerate) =>
@@ -139,12 +140,12 @@ public class StartFFmpegSessionHandler : IRequestHandler<StartFFmpegSession, Eit
         SessionMustBeInactive(request)
             .BindT(_ => FolderMustBeEmpty(request));
 
-    private Task<Validation<BaseError, Unit>> SessionMustBeInactive(StartFFmpegSession request)
+    private async Task<Validation<BaseError, Unit>> SessionMustBeInactive(StartFFmpegSession request)
     {
         var result = Optional(_ffmpegSegmenterService.TryAddWorker(request.ChannelNumber, null))
             .Where(success => success)
             .Map(_ => Unit.Default)
-            .ToValidation<BaseError>(new ChannelSessionAlreadyActive());
+            .ToValidation<BaseError>(new ChannelSessionAlreadyActive(await GetMultiVariantPlaylist(request)));
 
         if (result.IsFail && _ffmpegSegmenterService.TryGetWorker(
                 request.ChannelNumber,
@@ -153,7 +154,7 @@ public class StartFFmpegSessionHandler : IRequestHandler<StartFFmpegSession, Eit
             worker?.Touch(Option<string>.None);
         }
 
-        return result.AsTask();
+        return result;
     }
 
     private Task<Validation<BaseError, Unit>> FolderMustBeEmpty(StartFFmpegSession request)
@@ -166,4 +167,52 @@ public class StartFFmpegSessionHandler : IRequestHandler<StartFFmpegSession, Eit
 
         return Task.FromResult<Validation<BaseError, Unit>>(Unit.Default);
     }
+
+    private async Task<string> GetMultiVariantPlaylist(StartFFmpegSession request)
+    {
+        var variantPlaylist =
+            $"{request.Scheme}://{request.Host}{request.PathBase}/iptv/session/{request.ChannelNumber}/hls.m3u8{request.AccessTokenQuery}";
+
+        Option<ChannelStreamingSpecsViewModel> maybeStreamingSpecs =
+            await _mediator.Send(new GetChannelStreamingSpecs(request.ChannelNumber));
+        string resolution = string.Empty;
+        var bitrate = "10000000";
+        foreach (ChannelStreamingSpecsViewModel streamingSpecs in maybeStreamingSpecs)
+        {
+            string videoCodec = streamingSpecs.VideoFormat switch
+            {
+                FFmpegProfileVideoFormat.Av1 => "av01.0.01M.08",
+                FFmpegProfileVideoFormat.Hevc => "hvc1.1.6.L93.B0",
+                FFmpegProfileVideoFormat.H264 => "avc1.4D4028",
+                _ => string.Empty
+            };
+
+            string audioCodec = streamingSpecs.AudioFormat switch
+            {
+                FFmpegProfileAudioFormat.Ac3 => "ac-3",
+                FFmpegProfileAudioFormat.Aac or FFmpegProfileAudioFormat.AacLatm => "mp4a.40.2",
+                _ => string.Empty
+            };
+
+            List<string> codecStrings = [];
+            if (!string.IsNullOrWhiteSpace(videoCodec))
+            {
+                codecStrings.Add(videoCodec);
+            }
+
+            if (!string.IsNullOrWhiteSpace(audioCodec))
+            {
+                codecStrings.Add(audioCodec);
+            }
+
+            string codecs = codecStrings.Count > 0 ? $",CODECS=\"{string.Join(",", codecStrings)}\"" : string.Empty;
+            resolution = $",RESOLUTION={streamingSpecs.Width}x{streamingSpecs.Height}{codecs}";
+            bitrate = streamingSpecs.Bitrate.ToString(CultureInfo.InvariantCulture);
+        }
+
+        return $@"#EXTM3U
+#EXT-X-VERSION:3
+#EXT-X-STREAM-INF:BANDWIDTH={bitrate}{resolution}
+{variantPlaylist}";
+    }
 }

ErsatzTV.Core/Errors/ChannelSessionAlreadyActive.cs

@@ -1,8 +1,6 @@
 namespace ErsatzTV.Core.Errors;
 
-public class ChannelSessionAlreadyActive : BaseError
+public class ChannelSessionAlreadyActive(string multiVariantPlaylist) : BaseError("Channel already has HLS session")
 {
-    public ChannelSessionAlreadyActive() : base("Channel already has HLS session")
+    public string MultiVariantPlaylist { get; } = multiVariantPlaylist;
-    {
-    }
 }

ErsatzTV/Controllers/IptvController.cs

@@ -1,6 +1,4 @@
 using System.Diagnostics;
-using System.Globalization;
-using System.Text;
 using CliWrap;
 using ErsatzTV.Application.Channels;
 using ErsatzTV.Application.Images;
@@ -93,6 +91,15 @@ public class IptvController : StreamingControllerBase
             return NotFound();
         }
 
+        foreach (ChannelViewModel channel in maybeChannel)
+        {
+            // NEXT: MPEG-TS streams are not (yet?) supported
+            if (!channel.IsEnabled || channel.StreamingEngine is StreamingEngine.Next)
+            {
+                return NotFound();
+            }
+        }
+
         // if mode is "unspecified" - find the configured mode and set it or redirect
         if (string.IsNullOrWhiteSpace(mode) || mode == "mixed")
         {
@@ -224,11 +231,16 @@ public class IptvController : StreamingControllerBase
                     "Maybe starting ffmpeg session for channel {Channel}, mode {Mode}",
                     channelNumber,
                     mode);
-                var request = new StartFFmpegSession(channelNumber, mode, Request.Scheme, Request.Host.ToString());
+                var request = new StartFFmpegSession(
-                Either<BaseError, Unit> result = await _mediator.Send(request);
+                    channelNumber,
-                string multiVariantPlaylist = await GetMultiVariantPlaylist(channelNumber);
+                    mode,
+                    Request.Scheme,
+                    Request.Host.ToString(),
+                    Request.PathBase,
+                    AccessTokenQuery());
+                Either<BaseError, string> result = await _mediator.Send(request);
                 return result.Match<IActionResult>(
-                    _ =>
+                    multiVariantPlaylist =>
                     {
                         _logger.LogDebug(
                             "Session started; returning multi-variant playlist for channel {Channel}",
@@ -241,12 +253,12 @@ public class IptvController : StreamingControllerBase
                     {
                         switch (error)
                         {
-                            case ChannelSessionAlreadyActive:
+                            case ChannelSessionAlreadyActive active:
                                 _logger.LogDebug(
                                     "Session is already active; returning multi-variant playlist for channel {Channel}",
                                     channelNumber);
 
-                                return Content(multiVariantPlaylist, "application/vnd.apple.mpegurl");
+                                return Content(active.MultiVariantPlaylist, "application/vnd.apple.mpegurl");
                             // return RedirectPreserveMethod($"iptv/session/{channelNumber}/hls.m3u8");
                             default:
                                 _logger.LogWarning(
@@ -289,54 +301,6 @@ public class IptvController : StreamingControllerBase
     public async Task<IActionResult> GetStream(string channelNumber) =>
         await GetHlsDirectStream(channelNumber);
 
-    private async Task<string> GetMultiVariantPlaylist(string channelNumber)
-    {
-        var variantPlaylist =
-            $"{Request.Scheme}://{Request.Host}{Request.PathBase}/iptv/session/{channelNumber}/hls.m3u8{AccessTokenQuery()}";
-
-        Option<ChannelStreamingSpecsViewModel> maybeStreamingSpecs =
-            await _mediator.Send(new GetChannelStreamingSpecs(channelNumber));
-        string resolution = string.Empty;
-        var bitrate = "10000000";
-        foreach (ChannelStreamingSpecsViewModel streamingSpecs in maybeStreamingSpecs)
-        {
-            string videoCodec = streamingSpecs.VideoFormat switch
-            {
-                FFmpegProfileVideoFormat.Av1 => "av01.0.01M.08",
-                FFmpegProfileVideoFormat.Hevc => "hvc1.1.6.L93.B0",
-                FFmpegProfileVideoFormat.H264 => "avc1.4D4028",
-                _ => string.Empty
-            };
-
-            string audioCodec = streamingSpecs.AudioFormat switch
-            {
-                FFmpegProfileAudioFormat.Ac3 => "ac-3",
-                FFmpegProfileAudioFormat.Aac or FFmpegProfileAudioFormat.AacLatm => "mp4a.40.2",
-                _ => string.Empty
-            };
-
-            List<string> codecStrings = [];
-            if (!string.IsNullOrWhiteSpace(videoCodec))
-            {
-                codecStrings.Add(videoCodec);
-            }
-
-            if (!string.IsNullOrWhiteSpace(audioCodec))
-            {
-                codecStrings.Add(audioCodec);
-            }
-
-            string codecs = codecStrings.Count > 0 ? $",CODECS=\"{string.Join(",", codecStrings)}\"" : string.Empty;
-            resolution = $",RESOLUTION={streamingSpecs.Width}x{streamingSpecs.Height}{codecs}";
-            bitrate = streamingSpecs.Bitrate.ToString(CultureInfo.InvariantCulture);
-        }
-
-        return $@"#EXTM3U
-#EXT-X-VERSION:3
-#EXT-X-STREAM-INF:BANDWIDTH={bitrate}{resolution}
-{variantPlaylist}";
-    }
-
     private async Task<IActionResult> GetHlsDirectStream(string channelNumber)
     {
         var request = new GetPlayoutItemProcessByChannelNumber(