(ON_SCOPE_EXIT)ExampleActor.cpp

bool AExampleActor::Request()
{
  const TSharedRef<IHttpRequest> HttpRequest = FHttpModule::Get().CreateRequest();
  HttpRequest->SetVerb(TEXT("GET"));
  HttpRequest->SetHeader(TEXT("Content-Type"), TEXT("application/octet-stream"));
  HttpRequest->SetURL(/*何かしらの通信を行う先のURL*/);
  HttpRequest->OnProcessRequestComplete().BindUObject(this, &AExampleActor::OnReceived);
  return HttpRequest->ProcessRequest();
}

void AExampleActor::OnReceived(FHttpRequestPtr Request, FHttpResponsePtr Response, bool bSuccessful);
{
  bool bIsSuccess = false;
  // ON_SCOPE_EXIT内に書かれた処理はこの関数のスコープを抜ける際に呼び出される
  ON_SCOPE_EXIT
  {
    if (!bIsSuccess && OnFailure.IsBound())
    {
      OnFailure.Broadcast();
    }
  };

  if (!Request.IsValid())
  {
    return;
  }
  if (!Response.IsValid())
  {
    return;
  }
  if (Response->GetResponseCode() != EHttpResponseCodes::Ok)
  {
    return;
  }
  if (!bSuccessful)
  {
    return;
  }
  // Request成功時にbIsSuccessのフラグを立てることで失敗時のCallback呼び出しを抑制
  bIsSuccess = true;
  // Request成功時の処理
}