Push notifications

NostrStreamer/Services/EventStream.cs

@@ -0,0 +1,49 @@
+using Newtonsoft.Json;
+using Nostr.Client.Json;
+using Nostr.Client.Messages;
+using StackExchange.Redis;
+
+namespace NostrStreamer.Services;
+
+public class EventStream : BackgroundService
+{
+    private readonly ILogger<EventStream> _logger;
+    private readonly IServiceScopeFactory _scopeFactory;
+
+    public EventStream(ILogger<EventStream> logger, IServiceScopeFactory scopeFactory)
+    {
+        _logger = logger;
+        _scopeFactory = scopeFactory;
+    }
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            try
+            {
+                using var scope = _scopeFactory.CreateScope();
+                var redis = scope.ServiceProvider.GetRequiredService<ConnectionMultiplexer>();
+                var push = scope.ServiceProvider.GetRequiredService<PushSender>();
+                var queue = await redis.GetSubscriber().SubscribeAsync("event-stream");
+
+                while (!stoppingToken.IsCancellationRequested)
+                {
+                    var msg = await queue.ReadAsync(stoppingToken);
+
+                    var ev = JsonConvert.DeserializeObject<NostrEvent>(msg.Message!, NostrSerializer.Settings);
+                    if (ev is {Kind: NostrKind.LiveEvent})
+                    {
+                        push.Add(ev);
+                    }
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "failed {msg}", ex.Message);
+            }
+
+            await Task.Delay(TimeSpan.FromSeconds(10), stoppingToken);
+        }
+    }
+}