Package io.github.fablabsmc.fablabs.api.networking.v1.server

Interface ServerLoginContext

All Superinterfaces:
ListenerContext, ServerContext
public interface ServerLoginContext
extends ServerContext
Represents the context for ServerNetworking.getLoginReceiver(), in which a login query response packet is received.

Since the response is always received after the query is sent even when the client doesn't handle the channel of the query, isUnderstood() must be checked when handling in this context.

See Also:
ServerNetworking.getLoginReceiver()

  • Method Summary

    Modifier and Type Method Description
    net.minecraft.server.network.ServerLoginNetworkHandler getListener()
    Returns the packet listener that received this packet.
    PacketSender getPacketSender()
    Returns a packet sender that can send additional query request packets.
    boolean isUnderstood()
    Returns whether the original query request with the same query ID as this response was understood.
    void waitFor​(Future<?> future)
    Allows blocking client log-in until the future is done.

    Methods inherited from interface io.github.fablabsmc.fablabs.api.networking.v1.server.ServerContext

    getEngine

  • Method Details

    • getListener

      net.minecraft.server.network.ServerLoginNetworkHandler getListener()
      Returns the packet listener that received this packet.

      The packet listener offers access to the connection.

      In a server login context, the network handler is always a ServerLoginNetworkHandler.

      Specified by:
      getListener in interface ListenerContext
      Returns:
      the packet listener

    • getPacketSender

      PacketSender getPacketSender()
      Returns a packet sender that can send additional query request packets.

      If an upcoming query request packet cannot be immediately sent after receiving this packet, call waitFor(Future), which will make sure the client is not admitted until the future is done.

      Returns:
      the packet sender for query requests

    • isUnderstood

      boolean isUnderstood()
      Returns whether the original query request with the same query ID as this response was understood.

      If the query response is not understood, an empty packet byte buf will be passed as the buf for ChannelHandler.receive(io.github.fablabsmc.fablabs.api.networking.v1.ListenerContext, net.minecraft.network.PacketByteBuf).

      Since it is never guaranteed that a client can always understand query requests, this method should always be checked in packet reception.

      Returns:
      whether the query request was understood

    • waitFor

      void waitFor​(Future<?> future)
      Allows blocking client log-in until the future is done.

      Since packet reception happens on netty's event loops, this allows handlers to perform logic on the Server Thread, etc. For instance, a handler can prepare an upcoming query request or check necessary login data on the server thread.

      Here is an example where the player log-in is blocked so that a credential check and building of a followup query request can be performed properly on the logical server thread before the player successfully logs in: 

      
     ServerNetworking.getLoginReceiver().register(CHECK_CHANNEL, (context, buf) -> {
         if (!context.isUnderstood()) {
             handler.disconnect(new LiteralText("Only accept clients that can check!"));
             return;
         }
         String checkMessage = buf.readString(32767);
         ServerLoginNetworkHandler handler = context.getPacketListener();
         PacketSender sender = context.getPacketSender();
         MinecraftServer server = context.getEngine();
         // Just send the CompletableFuture returned by the server's submit method
         context.waitFor(server.submit(() -> {
             LoginInfoChecker checker = LoginInfoChecker.get(server);
             if (!checker.check(handler.getConnectionInfo(), checkMessage)) {
                 handler.disconnect(new LiteralText("Invalid credentials!"));
                 return;
             }
             sender.send(UPCOMING_CHECK, checker.buildSecondQueryPacket(handler, checkMessage));
         }));
     });
      Usually it is enough to pass the return value for ThreadExecutor.submit(Runnable) for future.

      Parameters:
      future - the future that must be done before the player can log in