Adding TabCompleteRequestEvent to be triggered when the client sends a tab to the server

api/src/main/java/com/velocitypowered/api/event/player/TabCompleteRequestEvent.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2019-2023 Velocity Contributors
+ *
+ * The Velocity API is licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in the api top-level directory.
+ */
+
+package com.velocitypowered.api.event.player;
+
+import com.velocitypowered.api.event.annotation.AwaitingEvent;
+import com.velocitypowered.api.proxy.Player;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * This event is fired after a tab complete request is sent by the player, for clients on
+ * 1.12.2 and below. You have the opportunity to modify the request sent to the remote server.
+ */
+@AwaitingEvent
+public class TabCompleteRequestEvent {
+
+    private final Player player;
+    private String partialMessage;
+
+    /**
+     * Constructs a new TabCompleteRequestEvent instance.
+     *
+     * @param player the player
+     * @param partialMessage the partial message
+     */
+    public TabCompleteRequestEvent(Player player, String partialMessage) {
+        this.player = checkNotNull(player, "player");
+        this.partialMessage = checkNotNull(partialMessage, "partialMessage");
+    }
+
+    /**
+     * Returns the player requesting the tab completion.
+     *
+     * @return the requesting player
+     */
+    public Player getPlayer() {
+        return player;
+    }
+
+    /**
+     * Returns the message being partially completed.
+     *
+     * @return the partial message
+     */
+    public String getPartialMessage() {
+        return partialMessage;
+    }
+
+    /**
+     * Modifies the message being partially completed.
+     *
+     */
+    public void setPartialMessage(String partialMessage) {
+        this.partialMessage = partialMessage;
+    }
+
+    @Override
+    public String toString() {
+        return "TabCompleteRequestEvent{"
+                + "player=" + player
+                + ", partialMessage='" + partialMessage + '\''
+                + '}';
+    }
+}

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -23,10 +23,7 @@
 import com.mojang.brigadier.suggestion.Suggestion;
 import com.velocitypowered.api.command.VelocityBrigadierMessage;
 import com.velocitypowered.api.event.connection.PluginMessageEvent;
-import com.velocitypowered.api.event.player.CookieReceiveEvent;
-import com.velocitypowered.api.event.player.PlayerChannelRegisterEvent;
-import com.velocitypowered.api.event.player.PlayerClientBrandEvent;
-import com.velocitypowered.api.event.player.TabCompleteEvent;
+import com.velocitypowered.api.event.player.*;
 import com.velocitypowered.api.event.player.configuration.PlayerEnteredConfigurationEvent;
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
@@ -712,6 +709,7 @@ private boolean handleRegularTabComplete(TabCompleteRequestPacket packet) {
    * @param response the tab complete response from the backend
    */
   public void handleTabCompleteResponse(TabCompleteResponsePacket response) {
+
     if (outstandingTabComplete != null && !outstandingTabComplete.isAssumeCommand()) {
       if (outstandingTabComplete.getCommand().startsWith("/")) {
         this.finishCommandTabComplete(outstandingTabComplete, response);
@@ -727,38 +725,47 @@ public void handleTabCompleteResponse(TabCompleteResponsePacket response) {
 
   private void finishCommandTabComplete(TabCompleteRequestPacket request,
                                         TabCompleteResponsePacket response) {
-    String command = request.getCommand().substring(1);
-    server.getCommandManager().offerBrigadierSuggestions(player, command)
-        .thenAcceptAsync(offers -> {
-          boolean legacy =
-              player.getProtocolVersion().lessThan(ProtocolVersion.MINECRAFT_1_13);
-          try {
-            for (Suggestion suggestion : offers.getList()) {
-              String offer = suggestion.getText();
-              offer = legacy && !offer.startsWith("/") ? "/" + offer : offer;
-              if (legacy && offer.startsWith(command)) {
-                offer = offer.substring(command.length());
-              }
-              ComponentHolder tooltip = null;
-              if (suggestion.getTooltip() != null
-                  && suggestion.getTooltip() instanceof VelocityBrigadierMessage) {
-                tooltip = new ComponentHolder(player.getProtocolVersion(),
-                    ((VelocityBrigadierMessage) suggestion.getTooltip()).asComponent());
-              }
-              response.getOffers().add(new Offer(offer, tooltip));
-            }
-            response.getOffers().sort(null);
-            player.getConnection().write(response);
-          } catch (Exception e) {
-            logger.error("Unable to provide tab list completions for {} for command '{}'",
-                player.getUsername(), command,
-                e);
-          }
+    server.getEventManager().fire(new TabCompleteRequestEvent(player, request.getCommand().substring(1)))
+        .thenAcceptAsync(e -> {
+          String command = e.getPartialMessage();
+          server.getCommandManager().offerBrigadierSuggestions(player, command)
+              .thenAcceptAsync(offers -> {
+                boolean legacy =
+                        player.getProtocolVersion().lessThan(ProtocolVersion.MINECRAFT_1_13);
+                try {
+                  for (Suggestion suggestion : offers.getList()) {
+                    String offer = suggestion.getText();
+                    offer = legacy && !offer.startsWith("/") ? "/" + offer : offer;
+                    if (legacy && offer.startsWith(command)) {
+                      offer = offer.substring(command.length());
+                    }
+                    ComponentHolder tooltip = null;
+                    if (suggestion.getTooltip() != null
+                            && suggestion.getTooltip() instanceof VelocityBrigadierMessage) {
+                      tooltip = new ComponentHolder(player.getProtocolVersion(),
+                              ((VelocityBrigadierMessage) suggestion.getTooltip()).asComponent());
+                    }
+                    response.getOffers().add(new Offer(offer, tooltip));
+                  }
+                  response.getOffers().sort(null);
+                  player.getConnection().write(response);
+                } catch (Exception ex) {
+                  logger.error("Unable to provide tab list completions for {} for command '{}'",
+                          player.getUsername(), command,
+                          ex);
+                }
+              }, player.getConnection().eventLoop()).exceptionally((ex) -> {
+                logger.error(
+                        "Exception while finishing command tab completion,"
+                                + " with request {} and response {}",
+                        request, response, ex);
+                return null;
+              });
         }, player.getConnection().eventLoop()).exceptionally((ex) -> {
           logger.error(
-              "Exception while finishing command tab completion,"
-                  + " with request {} and response {}",
-              request, response, ex);
+                  "Exception while finishing regular tab completion,"
+                          + " with request {} and response{}",
+                  request, response, ex);
           return null;
         });
   }