Apply Damage From Client to Server in C++

Development Programming & Scripting
1

So I have been searching for hours now but could not find a solution to this and replication still confuses me a bit, especially in C++.
I want my Characters to be able to apply damage to eachother but this only works from server to client so how can I get this to work in the opposite direction?

My code right now (a bit condensed):

ADevCharacter.h:

public:
UPROPERTY(Replicated)
		float Health;

ADevCharacter.cpp:

void ADevCharacter::Fire() {
	FCollisionQueryParams RV_TraceParams = FCollisionQueryParams(FName(TEXT("RV_Trace")), true, this);
	RV_TraceParams.bTraceComplex = true;
	RV_TraceParams.bTraceAsyncScene = true;
	RV_TraceParams.bReturnPhysicalMaterial = false;

	FHitResult RV_Hit(ForceInit);

	FVector Start = this->GetActorLocation();
	FVector End = (this->GetActorForwardVector() * 300.f) + this->GetActorLocation();

	bool isHit = GetWorld()->LineTraceSingleByObjectType(RV_Hit, Start, End, ECC_Pawn, RV_TraceParams);

	DrawDebugLine(GetWorld(), Start, End, FColor::Green, false, 1, 0, 5);

	TSubclassOf<UDamageType> P;

	ADevCharacter* HitChar = Cast<ADevCharacter>(RV_Hit.GetActor());
	if (isHit) {

		FPointDamageEvent* DamageEvent = new FPointDamageEvent();
		GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Yellow, TEXT("HIT"));

		UGameplayStatics::ApplyPointDamage(HitChar,10.f, this->GetActorForwardVector(),RV_Hit, this->GetController(), this, P);
	}
}

float ADevCharacter::TakeDamage(float DamageAmount, FDamageEvent const &DamageEvent, AController *EventInstigatior, AActor *DamageCauser) {
	Health -=  DamageAmount;
	if (Health < 0) {
		AWarPlayerController* PlayerController = Cast<AWarPlayerController>(Controller);
		if (PlayerController) {
			PlayerController->OnKilled();
			Destroy();
		}	
	}

	return DamageAmount;
}
2

You definitely wouldn’t want it to work in the opposite direction. Unreal Engine uses an Authoritative Server model, meaning the server has control over replicated values. This is to prevent hacking of important variables such as health on the client side. You should do all of your hit detection on the server.

3

In blueprints there is a server function ApplyDamage. It is probably there in C++ too