AGameModeBase::PreLogin

function Engine Since 4.14

#include "GameFramework/GameModeBase.h"

Access: public Specifiers: virtual

Description

Called before `Login` to accept or reject an incoming connection. Set `ErrorMessage` to a non-empty string to deny the player with that reason.

Caveats & Gotchas

• There may be significant time between `PreLogin` and the subsequent `Login` call — do not store per-connection state that is keyed on the connection object, as conditions may change.
• If you need to perform an async check (e.g. backend ban lookup), override `PreLoginAsync` instead. The synchronous `PreLogin` blocks the game thread for the duration of the call.
• The `FGameModeEvents::GameModePreLoginEvent` global delegate is broadcast inside the base implementation. Overriding without calling `Super` will prevent plugins and online subsystems from running their own pre-login checks.

Signature

virtual void PreLogin(const FString& Options, const FString& Address, const FUniqueNetIdRepl& UniqueId, FString& ErrorMessage)

Parameters

Name	Type	Description	Default
Options	const FString&	The URL options passed by the connecting client (e.g. name, password).	—
Address	const FString&	The network address of the connecting player.	—
UniqueId	const FUniqueNetIdRepl&	The platform-specific unique ID of the connecting player.	—
ErrorMessage	FString&	Output error message. Set to a non-empty string to reject the player.	—

Return Type

void

Example

Reject players who lack a required password C++

void AMyGameMode::PreLogin(const FString& Options, const FString& Address,
    const FUniqueNetIdRepl& UniqueId, FString& ErrorMessage)
{
    Super::PreLogin(Options, Address, UniqueId, ErrorMessage);

    // If super already rejected, don't overwrite the message
    if (!ErrorMessage.IsEmpty()) return;

    FString Password = UGameplayStatics::ParseOption(Options, TEXT("Password"));
    if (Password != ServerPassword)
    {
        ErrorMessage = TEXT("Incorrect server password.");
    }
}

Version History

Introduced in: 4.14

Version	Status	Notes
5.6	stable	—

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