Add Accept-Language header support and cleanup translations (#16488)

* Add Accept-Language header support for per-request localization

* Use native middleware

* Cleanup

* Add Fallback

* Build BCP47 map reflexively

* Address review comments

1 files changed, 7 insertions, 2 deletions

diff --git a/Emby.Server.Implementations/HttpServer/WebSocketManager.cs b/Emby.Server.Implementations/HttpServer/WebSocketManager.cs
index cb5b3993b8..072034c4bf 100644
--- a/Emby.Server.Implementations/HttpServer/WebSocketManager.cs
+++ b/Emby.Server.Implementations/HttpServer/WebSocketManager.cs
@@ -4,6 +4,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using System.Net.WebSockets;
 using System.Threading.Tasks;
@@ -47,14 +48,18 @@ namespace Emby.Server.Implementations.HttpServer
                 _logger.LogInformation("WS {IP} request", context.Connection.RemoteIpAddress);
 
                 WebSocket webSocket = await context.WebSockets.AcceptWebSocketAsync().ConfigureAwait(false);
-
                 var connection = new WebSocketConnection(
                     _loggerFactory.CreateLogger<WebSocketConnection>(),
                     webSocket,
                     authorizationInfo,
                     context.GetNormalizedRemoteIP())
                 {
-                    OnReceive = ProcessWebSocketMessageReceived
+                    RequestUICulture = CultureInfo.CurrentUICulture
+                };
+                connection.OnReceive = result =>
+                {
+                    connection.ApplyRequestCulture();
+                    return ProcessWebSocketMessageReceived(result);
                 };
                 await using (connection.ConfigureAwait(false))
                 {