Add support for upcoming CSP/CM feature to select a specific car slot when connecting

Author: compujuckel

AssettoServer/Server/ACServer.cs

@@ -71,7 +71,7 @@ public ACServer(
         _applicationLifetime = applicationLifetime;
         _trackParamsProvider = trackParamsProvider;
 
-        _autostartServices = new List<IHostedService> { weatherManager, sessionManager, tcpServer, udpServer };
+        _autostartServices = [weatherManager, sessionManager, tcpServer, udpServer];
         _autostartServices.AddRange(autostartServices);
         _autostartServices.Add(kunosLobbyRegistration);
 
@@ -80,6 +80,7 @@ public ACServer(
         cspFeatureManager.Add(new CSPFeature { Name = "SPECTATING_AWARE" });
         cspFeatureManager.Add(new CSPFeature { Name = "LOWER_CLIENTS_SENDING_RATE" });
         cspFeatureManager.Add(new CSPFeature { Name = "EMOJI" });
+        cspFeatureManager.Add(new CSPFeature { Name = "SLOT_INDEX" });
 
         if (_configuration.Extra.EnableClientMessages)
         {

AssettoServer/Server/EntryCarManager.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Concurrent;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -178,16 +179,33 @@ internal async Task<bool> TrySecureSlotAsync(ACTcpClient client, HandshakeReques
 
             if (ConnectedCars.Count >= _configuration.Server.MaxClients)
                 return false;
-            
-            for (int i = 0; i < EntryCars.Length; i++)
+
+            IEnumerable<EntryCar> candidates;
+
+            // Support for SLOT_INDEX CSP feature. CSP sends "car_model:n" where n is the specific slot index the user wants to connect to.
+            var slotIndexSeparator = handshakeRequest.RequestedCar.IndexOf(':');
+            if (slotIndexSeparator >= 0)
             {
-                EntryCar entryCar = EntryCars[i];
+                var requestedSlotIndex = int.Parse(handshakeRequest.RequestedCar.AsSpan(slotIndexSeparator + 1));
+                var requestedCarName = handshakeRequest.RequestedCar[..slotIndexSeparator];
+                var candidate = EntryCars.Where(c => c.Model == requestedCarName).ElementAtOrDefault(requestedSlotIndex);
 
-                bool isAdmin = await _adminService.IsAdminAsync(handshakeRequest.Guid);
+                if (candidate == null)
+                {
+                    return false;
+                }
+                
+                candidates = [candidate];
+            }
+            else
+            {
+                candidates = EntryCars.Where(c => c.Model == handshakeRequest.RequestedCar);
+            }
 
-                if (entryCar.Client == null
-                    && handshakeRequest.RequestedCar == entryCar.Model
-                    && (isAdmin || _openSlotFilterChain.Value.IsSlotOpen(entryCar, handshakeRequest.Guid)))
+            var isAdmin = await _adminService.IsAdminAsync(handshakeRequest.Guid);
+            foreach (var entryCar in candidates)
+            {
+                if (entryCar.Client == null && (isAdmin || _openSlotFilterChain.Value.IsSlotOpen(entryCar, handshakeRequest.Guid)))
                 {
                     entryCar.Reset();
                     entryCar.Client = client;

AssettoServer/Server/Steam/SteamManager.cs

@@ -39,7 +39,7 @@ public async Task<bool> ValidateSessionTicketAsync(byte[]? sessionTicket, ulong
                 client.Logger.Information("{ClientName} ({SteamId}) is using Steam family sharing, owner {OwnerSteamId}", client.Name, client.Guid, client.OwnerGuid);
             }
 
-            client.Logger.Information("Steam authentication succeeded for {ClientName} ({SessionId})", client.Name, client.SessionId);
+            client.Logger.Information("Steam authentication succeeded for {ClientName} ({SteamId})", client.Name, client.Guid);
         }
         else
         {