Implement custom view counters

NostrStreamer/Controllers/PlaylistController.cs

@@ -16,9 +16,10 @@ public class PlaylistController : Controller
     private readonly IServiceScopeFactory _scopeFactory;
     private readonly HttpClient _client;
     private readonly SrsApi _srsApi;
+    private readonly ViewCounter _viewCounter;
 
     public PlaylistController(Config config, IMemoryCache cache, ILogger<PlaylistController> logger, IServiceScopeFactory scopeFactory,
-        HttpClient client, SrsApi srsApi)
+        HttpClient client, SrsApi srsApi, ViewCounter viewCounter)
     {
         _config = config;
         _cache = cache;
@@ -26,10 +27,11 @@ public class PlaylistController : Controller
         _scopeFactory = scopeFactory;
         _client = client;
         _srsApi = srsApi;
+        _viewCounter = viewCounter;
     }
 
     [HttpGet("{variant}/{pubkey}.m3u8")]
-    public async Task RewritePlaylist([FromRoute] string pubkey, [FromRoute] string variant)
+    public async Task RewritePlaylist([FromRoute] string pubkey, [FromRoute] string variant, [FromQuery(Name = "hls_ctx")] string hlsCtx)
     {
         var key = await GetStreamKey(pubkey);
         if (string.IsNullOrEmpty(key))
@@ -74,6 +76,7 @@ public class PlaylistController : Controller
         }
 
         Response.Body.Close();
+        _viewCounter.Activity(key, hlsCtx);
     }
 
     [HttpGet("{pubkey}.m3u8")]
@@ -92,6 +95,7 @@ public class PlaylistController : Controller
             Response.StatusCode = 404;
             return;
         }
+
         Response.ContentType = "application/x-mpegurl";
         await using var sw = new StreamWriter(Response.Body);
 
@@ -113,7 +117,9 @@ public class PlaylistController : Controller
             await sw.WriteLineAsync(
                 $"#EXT-X-STREAM-INF:{string.Join(",", allArgs)},CODECS=\"avc1.640028,mp4a.40.2\"");
 
-            var u = new Uri(_config.DataHost, $"{variant.Name}/{pubkey}.m3u8{(!string.IsNullOrEmpty(hlsCtx) ? $"?hls_ctx={hlsCtx}" : "")}");
+            var u = new Uri(_config.DataHost,
+                $"{variant.Name}/{pubkey}.m3u8{(!string.IsNullOrEmpty(hlsCtx) ? $"?hls_ctx={hlsCtx}" : "")}");
+
             await sw.WriteLineAsync(u.ToString());
         }
     }

NostrStreamer/Program.cs

@@ -50,6 +50,8 @@ internal static class Program
         services.AddTransient<StreamManager>();
         services.AddTransient<SrsApi>();
         services.AddHostedService<BackgroundStreamManager>();
+        services.AddSingleton<ViewCounter>();
+        services.AddHostedService<ViewCounterDecay>();
         
         // lnd services
         services.AddSingleton<LndNode>();

NostrStreamer/Services/BackgroundStreamManager.cs

@@ -21,14 +21,13 @@ public class BackgroundStreamManager : BackgroundService
 
                 var streamManager = scope.ServiceProvider.GetRequiredService<StreamManager>();
                 var srsApi = scope.ServiceProvider.GetRequiredService<SrsApi>();
+                var viewCounter = scope.ServiceProvider.GetRequiredService<ViewCounter>();
 
-                var clients = await srsApi.ListClients();
-                var streams = clients.Where(a => !a.Publish).GroupBy(a => a.Url);
-                foreach (var stream in streams)
+                var streams = await srsApi.ListStreams();
+                foreach (var stream in streams.GroupBy(a => a.Name))
                 {
-                    var viewers = 0; //stream.Select(a => a.Ip).Distinct().Count();
-                    var streamKey = stream.Key.Split("/").Last();
-                    await streamManager.UpdateViewers(streamKey, viewers);
+                    var viewers = viewCounter.Current(stream.Key);
+                    await streamManager.UpdateViewers(stream.Key, viewers);
                 }
             }
             catch (Exception ex)

NostrStreamer/Services/ViewCounter.cs

@@ -0,0 +1,77 @@
+using System.Collections.Concurrent;
+
+namespace NostrStreamer.Services;
+
+public class ViewCounter
+{
+    private readonly ConcurrentDictionary<string, Dictionary<string, DateTime>> _sessions = new();
+
+    public void Activity(string key, string token)
+    {
+        if (!_sessions.ContainsKey(key))
+        {
+            _sessions.TryAdd(key, new());
+        }
+        if (_sessions.TryGetValue(key, out var x))
+        {
+            x[token] = DateTime.Now;
+        }
+    }
+
+    public void Decay()
+    {
+        foreach (var k in _sessions.Keys)
+        {
+            if (_sessions.TryGetValue(k, out var x))
+            {
+                _sessions[k] = x
+                    .Where(a => a.Value > DateTime.Now.Subtract(TimeSpan.FromMinutes(2)))
+                    .ToDictionary(a => a.Key, b => b.Value);
+
+                if (_sessions[k].Count == 0)
+                {
+                    _sessions.TryRemove(k, out _);
+                }
+            }
+        }
+    }
+
+    public int Current(string key)
+    {
+        if (_sessions.TryGetValue(key, out var x))
+        {
+            return x.Count;
+        }
+
+        return 0;
+    }
+}
+
+public class ViewCounterDecay : BackgroundService
+{
+    private readonly ViewCounter _viewCounter;
+    private readonly ILogger<ViewCounterDecay> _logger;
+
+    public ViewCounterDecay(ViewCounter viewCounter, ILogger<ViewCounterDecay> logger)
+    {
+        _viewCounter = viewCounter;
+        _logger = logger;
+    }
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            try
+            {
+                _viewCounter.Decay();
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Something went wrong");
+            }
+
+            await Task.Delay(TimeSpan.FromMinutes(1), stoppingToken);
+        }
+    }
+}