feat: Catch a WebSocketException and convert to a warning

Client disconnections are normal - always log them as warnings, not errors

Author: Ljutyj

src/VirtoCommerce.Xapi.Core/Extensions/ApplicationBuilderExtensions.cs

@@ -1,10 +1,12 @@
 using System;
+using System.Net.WebSockets;
 using GraphQL.Server.Transports.AspNetCore;
 using GraphQL.Server.Transports.AspNetCore.WebSockets;
 using GraphQL.Server.Ui.GraphiQL;
 using GraphQL.Types;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using VirtoCommerce.Xapi.Core.Infrastructure;
 using VirtoCommerce.Xapi.Core.Models;
@@ -24,6 +26,32 @@ public static IApplicationBuilder UseScopedSchema<TMarker>(this IApplicationBuil
     public static IApplicationBuilder UseSchemaGraphQL<TSchema>(this IApplicationBuilder builder, bool schemaIntrospectionEnabled = true, string schemaPath = null)
         where TSchema : ISchema
     {
+        var loggerFactory = builder.ApplicationServices.GetRequiredService<ILoggerFactory>();
+        var logger = loggerFactory.CreateLogger("GraphQLWebSocket");
+
+        builder.Use(async (_, next) =>
+        {
+            try
+            {
+                await next();
+            }
+            catch (WebSocketException wsEx) when (
+                wsEx.WebSocketErrorCode == WebSocketError.ConnectionClosedPrematurely ||
+                wsEx.WebSocketErrorCode == WebSocketError.InvalidState)
+            {
+                // These are common and expected during client disconnects
+                logger.LogWarning(
+                    "WebSocket disconnected: {ErrorCode} - {Message}",
+                    wsEx.WebSocketErrorCode,
+                    wsEx.Message);
+            }
+            catch (WebSocketException wsEx)
+            {
+                // Other WebSocket errors might need attention
+                logger.LogWarning(wsEx, "WebSocket error occurred");
+            }
+        });
+
         var graphQlPath = string.IsNullOrEmpty(schemaPath)
             ? GraphQlPath
             : $"{GraphQlPath}/{schemaPath}";