feat: allow attaching extra ping data on modern

This patch allows modern Minecraft servers to include additional match data in the ping response by splitting off extra ping data attachments into a ExtraPingDataRequestEvent that individual platforms can call with their own implementation that can be appropriately handled afterwards.

On SP, this is handled as usual. On modern Minecraft, this is implemented using a ProtocolLib hook.

Signed-off-by: TTtie <[email protected]>

Author: TTtie

core/src/main/java/tc/oc/pgm/listeners/ServerPingDataListener.java

@@ -1,7 +1,6 @@
 package tc.oc.pgm.listeners;
 
 import static tc.oc.pgm.util.Assert.assertNotNull;
-import static tc.oc.pgm.util.bukkit.MiscUtils.MISC_UTILS;
 
 import com.google.common.cache.CacheBuilder;
 import com.google.common.cache.CacheLoader;
@@ -30,6 +29,7 @@
 import tc.oc.pgm.api.match.event.MatchLoadEvent;
 import tc.oc.pgm.map.contrib.PlayerContributor;
 import tc.oc.pgm.util.ClassLogger;
+import tc.oc.pgm.util.event.ExtraPingDataRequestEvent;
 
 public class ServerPingDataListener implements Listener {
 
@@ -66,7 +66,7 @@ public void onMatchLoad(MatchLoadEvent event) {
 
   @EventHandler
   public void onServerListPing(ServerListPingEvent event) {
-    if (!ready.get() || legacySportPaper.get()) return;
+    if (!ready.get()) return;
 
     // Remove vanished players from player sample/ping count
     Iterator<Player> playerSample = event.iterator();
@@ -76,9 +76,14 @@ public void onServerListPing(ServerListPingEvent event) {
         playerSample.remove();
       }
     }
+  }
+
+  @EventHandler
+  public void onExtraDataRequest(ExtraPingDataRequestEvent event) {
+    if (legacySportPaper.get()) return;
 
     try {
-      JsonObject root = MISC_UTILS.getServerListExtra(event, PGM.get());
+      JsonObject root = event.getServerListExtra(PGM.get());
       this.matchManager.getMatches().forEachRemaining(match -> {
         String matchId = match.getId();
         try {

platform/platform-modern/src/main/java/tc/oc/pgm/platform/modern/impl/ModernMiscUtil.java

@@ -2,7 +2,6 @@
 
 import static tc.oc.pgm.util.platform.Supports.Variant.PAPER;
 
-import com.google.gson.JsonObject;
 import java.nio.file.Path;
 import java.util.List;
 import net.kyori.adventure.key.Key;
@@ -33,9 +32,7 @@
 import org.bukkit.event.entity.EntityDamageEvent;
 import org.bukkit.event.entity.EntityExplodeEvent;
 import org.bukkit.event.entity.PlayerDeathEvent;
-import org.bukkit.event.server.ServerListPingEvent;
 import org.bukkit.inventory.ItemStack;
-import org.bukkit.plugin.Plugin;
 import org.bukkit.scoreboard.Team;
 import tc.oc.pgm.platform.modern.material.ModernBlockMaterialData;
 import tc.oc.pgm.util.DataVersions;
@@ -45,12 +42,6 @@
 
 @Supports(value = PAPER, minVersion = "1.21.5")
 public class ModernMiscUtil implements MiscUtils {
-  @Override
-  public JsonObject getServerListExtra(ServerListPingEvent event, Plugin plugin) {
-    // TODO: PLATFORM 1.20 no support for extra fields in server ping
-    return new JsonObject();
-  }
-
   @Override
   public EventException createEventException(Throwable cause, Event event) {
     return new EventException(cause);

platform/platform-modern/src/main/java/tc/oc/pgm/platform/modern/packets/PacketManipulations.java

@@ -1,13 +1,22 @@
 package tc.oc.pgm.platform.modern.packets;
 
 import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.ProtocolLibrary;
 import com.comphenix.protocol.events.ListenerPriority;
 import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.injector.netty.WirePacket;
+import com.google.gson.JsonObject;
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.Dynamic;
+import com.mojang.serialization.JsonOps;
+import io.netty.buffer.Unpooled;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import net.minecraft.core.particles.ParticleOptions;
+import net.minecraft.network.FriendlyByteBuf;
 import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket;
+import net.minecraft.network.protocol.status.ServerStatus;
 import net.minecraft.network.syncher.EntityDataAccessor;
 import net.minecraft.network.syncher.SynchedEntityData;
 import net.minecraft.world.entity.Entity;
@@ -16,6 +25,7 @@
 import org.bukkit.plugin.Plugin;
 import tc.oc.pgm.platform.modern.listeners.PlayerTracker;
 import tc.oc.pgm.platform.modern.util.Packets;
+import tc.oc.pgm.util.event.ExtraPingDataRequestEvent;
 import tc.oc.pgm.util.reflect.ReflectionUtils;
 
 @SuppressWarnings("unchecked")
@@ -45,7 +55,8 @@ public PacketManipulations(Plugin plugin, PlayerTracker tracker) {
         Map.of(
             PacketType.Play.Server.ENTITY_STATUS, this::handleEntityStatus,
             PacketType.Play.Server.PLAYER_COMBAT_KILL, this::handleCombatKill,
-            PacketType.Play.Server.ENTITY_METADATA, this::handleEntityMetadata));
+            PacketType.Play.Server.ENTITY_METADATA, this::handleEntityMetadata,
+            PacketType.Status.Server.SERVER_INFO, this::handleServerPing));
   }
 
   private void handleEntityStatus(PacketEvent event) {
@@ -127,4 +138,37 @@ private void handleEntityMetadata(PacketEvent event) {
       if (!checkHealth && !hideParticles) return;
     }
   }
+
+  private void handleServerPing(PacketEvent event) {
+    JsonObject pingExtra = new JsonObject();
+    new ExtraPingDataRequestEvent() {
+      @Override
+      public JsonObject getServerListExtra(Plugin plugin) {
+        return (JsonObject)
+            pingExtra.asMap().computeIfAbsent(plugin.namespace(), k -> new JsonObject());
+      }
+    }.callEvent();
+
+    if (!pingExtra.isEmpty()) {
+      // Encode the response manually, otherwise the extra data will get lost
+      var serverPing = (ServerStatus) event.getPacket().getServerPings().read(0).getHandle();
+      var jsonData = ServerStatus.CODEC
+          .encodeStart(JsonOps.INSTANCE, serverPing)
+          .getOrThrow()
+          .getAsJsonObject();
+
+      jsonData.add("bukkit_extra", pingExtra);
+
+      var byteBuf = new FriendlyByteBuf(Unpooled.buffer());
+      byteBuf.writeJsonWithCodec(Codec.PASSTHROUGH, new Dynamic<>(JsonOps.INSTANCE, jsonData));
+
+      ProtocolLibrary.getProtocolManager()
+          .sendWirePacket(
+              event.getPlayer(),
+              new WirePacket(PacketType.Status.Server.SERVER_INFO, byteBuf.array()));
+
+      byteBuf.release();
+      event.setCancelled(true);
+    }
+  }
 }

platform/platform-sportpaper/src/main/java/tc/oc/pgm/platform/sportpaper/SportPaperListener.java

@@ -2,8 +2,11 @@
 
 import static tc.oc.pgm.util.event.EventUtil.handleCall;
 
+import com.google.gson.JsonObject;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
+import org.bukkit.plugin.Plugin;
+import tc.oc.pgm.util.event.ExtraPingDataRequestEvent;
 import tc.oc.pgm.util.event.block.BlockDispenseEntityEvent;
 import tc.oc.pgm.util.event.block.BlockFallEvent;
 import tc.oc.pgm.util.event.entity.EntityDespawnInVoidEvent;
@@ -19,7 +22,6 @@
 import tc.oc.pgm.util.event.player.PlayerSpawnEntityEvent;
 
 public class SportPaperListener implements Listener {
-
   @EventHandler(ignoreCancelled = true)
   public void onBlockFall(org.bukkit.event.block.BlockFallEvent sportEvent) {
     BlockFallEvent pgmEvent = new BlockFallEvent(sportEvent.getBlock(), sportEvent.getEntity());
@@ -108,4 +110,16 @@ public void onEntityDespawn(org.bukkit.event.entity.EntityDespawnInVoidEvent spo
     EntityDespawnInVoidEvent pgmEvent = new EntityDespawnInVoidEvent(sportEvent.getEntity());
     handleCall(pgmEvent, sportEvent);
   }
+
+  @EventHandler
+  public void onServerPing(final org.bukkit.event.server.ServerListPingEvent event) {
+    handleCall(
+        new ExtraPingDataRequestEvent() {
+          @Override
+          public JsonObject getServerListExtra(Plugin plugin) {
+            return event.getOrCreateExtra(plugin);
+          }
+        },
+        event);
+  }
 }

platform/platform-sportpaper/src/main/java/tc/oc/pgm/platform/sportpaper/impl/SpMiscUtil.java

@@ -4,7 +4,6 @@
 import static tc.oc.pgm.util.platform.Supports.Priority.HIGH;
 import static tc.oc.pgm.util.platform.Supports.Variant.SPORTPAPER;
 
-import com.google.gson.JsonObject;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.List;
@@ -30,9 +29,7 @@
 import org.bukkit.event.entity.EntityDamageEvent;
 import org.bukkit.event.entity.EntityExplodeEvent;
 import org.bukkit.event.entity.PlayerDeathEvent;
-import org.bukkit.event.server.ServerListPingEvent;
 import org.bukkit.inventory.ItemStack;
-import org.bukkit.plugin.Plugin;
 import tc.oc.pgm.platform.sportpaper.material.LegacyMaterialData;
 import tc.oc.pgm.util.DataVersions;
 import tc.oc.pgm.util.bukkit.MiscUtils;
@@ -49,11 +46,6 @@ public boolean yield(Event event) {
     return true;
   }
 
-  @Override
-  public JsonObject getServerListExtra(ServerListPingEvent event, Plugin plugin) {
-    return event.getOrCreateExtra(plugin);
-  }
-
   @Override
   public EventException createEventException(Throwable cause, Event event) {
     return new EventException(cause, event);

util/src/main/java/tc/oc/pgm/util/bukkit/MiscUtils.java

@@ -1,6 +1,5 @@
 package tc.oc.pgm.util.bukkit;
 
-import com.google.gson.JsonObject;
 import java.nio.file.Path;
 import java.util.List;
 import net.kyori.adventure.key.Key;
@@ -19,9 +18,7 @@
 import org.bukkit.event.entity.EntityDamageEvent;
 import org.bukkit.event.entity.EntityExplodeEvent;
 import org.bukkit.event.entity.PlayerDeathEvent;
-import org.bukkit.event.server.ServerListPingEvent;
 import org.bukkit.inventory.ItemStack;
-import org.bukkit.plugin.Plugin;
 import org.bukkit.scoreboard.Team;
 import tc.oc.pgm.util.material.BlockMaterialData;
 import tc.oc.pgm.util.platform.Platform;
@@ -33,10 +30,6 @@ default boolean yield(Event event) {
     return false;
   }
 
-  default JsonObject getServerListExtra(ServerListPingEvent event, Plugin plugin) {
-    return new JsonObject();
-  }
-
   default EventException createEventException(Throwable cause, Event event) {
     return new EventException(cause);
   }

util/src/main/java/tc/oc/pgm/util/event/ExtraPingDataRequestEvent.java

@@ -0,0 +1,25 @@
+package tc.oc.pgm.util.event;
+
+import com.google.gson.JsonObject;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.server.ServerEvent;
+import org.bukkit.plugin.Plugin;
+
+/**
+ * Called by individual platform implementations to allow listeners to attach additional server ping
+ * data
+ */
+public abstract class ExtraPingDataRequestEvent extends ServerEvent {
+  public abstract JsonObject getServerListExtra(Plugin plugin);
+
+  private static final HandlerList handlers = new HandlerList();
+
+  @Override
+  public HandlerList getHandlers() {
+    return handlers;
+  }
+
+  public static HandlerList getHandlerList() {
+    return handlers;
+  }
+}