Network Error force loads Entry map for client when server shuts down

Development Programming & Scripting
1

This seems to have been an issue for some time now without being resolved.
If a listen server disconnects, the connected client in the session will get a Network Error event and is then loaded into Entry, regardless if that Network Error event is connected to a Open Level or console command (open mapname) these will be ignored and the client will end up on the Entry map.

I can’t find any way of fixing this and it is a problem. Any advice is appreciated!

2 Likes
2

Did you ever find a solution to this?

3

Not really, I did some hacky fix by setting a bool when the network error occurs, and if that bool is set when the entry map loads, it instantly loads the menu map, error messages etc. It works tho.

1 Like
4

yeah, I actually did similar, not happy about it though. I have it that on network error, I quickly load the main menu (from the entry map Splash screen), and show an error message. Not so pretty.

5

guys, seems like this is the only solution, even if we don’t like it. i checked ShooterGame example, and they do the same, after disconnect they change GameState to ErrorMessage, and game opens default level, then this game state value is applied

6

While I’m sure there’s better ways, this seemed to do the trick for me.

void HandleNetworkFailure(UWorld* World, UNetDriver* NetDriver, ENetworkFailure::Type FailureType, const FString& ErrorString);

HandleNetworkFailure is found in the UnrealEngine.h file and can be overridden - this has other interesting stuff like OnTravelFailure.

void UMyGameInstance::HandleNetworkFailure(UWorld* World, UNetDriver* NetDriver, ENetworkFailure::Type FailureType, const FString& ErrorString) {
	if (FailureType == ENetworkFailure::FailureReceived || FailureType == ENetworkFailure::ConnectionLost) {
		APlayerController* PlayerController = GetFirstLocalPlayerController();
		if (!ensure(PlayerController != nullptr)) return;

		PlayerController->ClientTravel("/Game/Maps/MainMenu", ETravelType::TRAVEL_Absolute);
	}
}

The function can be implemented as shown above. Running multiple instances via commandline with log reveiled the FailureType to be FailureReceived and ConnectionLost so do a check - eventually it’ll be caught and you can do a client travel to the main menu.

	GetEngine()->OnNetworkFailure().AddUObject(this, &UMyGameInstance::HandleNetworkFailure);

Lastly, add a delegate with the function to the OnNetworkFailure event in the Init function of your GameInstance, or where you prefer, and it should be working.

1 Like
7

I’ve also implemented your solution, but I still cannot control clientTraveling to the EntryMap. I don’t want the client to travel anywhere.
How do you choose whether/where the client will travel to post-NetworkError?

1 Like
8

UGameMapsSettings::SetGameDefaultMap(levelName);

9

Funny, I implemented the exact same solution and found this topic after -_-

10

It raises a 'package not found' error… If set default map to None

11

found.

void UEngine::HandleDisconnect( UWorld *InWorld, UNetDriver *NetDriver )
{
	// There must be some context for this disconnect
	check(InWorld || NetDriver);

	// InWorld might be null. It might also not map to any valid world context (for example, a pending net game disconnect)
	// If there is a context for this world, setup client travel.
	if (FWorldContext* WorldContext = GetWorldContextFromWorld(InWorld))
	{
		// Remove ?Listen parameter, if it exists
		WorldContext->LastURL.RemoveOption( TEXT("Listen") );
		WorldContext->LastURL.RemoveOption( TEXT("LAN") );

		// Net driver destruction will occur during LoadMap (prevents GetNetMode from changing output for the remainder of the frame)
		// The ?closed option will also make sure any PendingNetGame is cancelled in Browse
		SetClientTravel( InWorld, TEXT("?closed"), TRAVEL_Absolute );
	}
	else if (NetDriver)
	{
		// If the NetDriver that failed was a pending netgame driver, cancel the PendingNetGame
		CancelPending(NetDriver);

		// Shut down any existing game connections
		if (InWorld)
		{
			// Call this to remove the NetDriver from the world context's ActiveNetDriver list
			DestroyNamedNetDriver(InWorld, NetDriver->NetDriverName);
		}
		else
		{
			NetDriver->Shutdown();
			NetDriver->LowLevelDestroy();

			// In this case, the world is null and something went wrong, so we should travel back to the default world so that we
			// can get back to a good state.
			for (FWorldContext& PotentialWorldContext : WorldList)
			{
				if (PotentialWorldContext.WorldType == EWorldType::Game)
				{
					FURL DefaultURL;
					DefaultURL.LoadURLConfig(TEXT("DefaultPlayer"), GGameIni);
					const UGameMapsSettings* GameMapsSettings = GetDefault<UGameMapsSettings>();
					if (GameMapsSettings)
					{
						PotentialWorldContext.TravelURL = FURL(&DefaultURL, *(GameMapsSettings->GetGameDefaultMap() + GameMapsSettings->LocalMapOptions), TRAVEL_Partial).ToString();
						PotentialWorldContext.TravelType = TRAVEL_Partial;
					}
				}
			}
		}
	}
}

You need to change this function has you need.
Mostly this line
PotentialWorldContext.TravelURL = FURL(&DefaultURL, *(GameMapsSettings->GetGameDefaultMap() + GameMapsSettings->LocalMapOptions), TRAVEL_Partial).ToString();

Require to build yourself the engine by the way.