From 21e72556c964154deee5ed7e5f81690ddaf17a1e Mon Sep 17 00:00:00 2001
From: Andrew Steinborn <git@steinborn.me>
Date: Sat, 11 Aug 2018 06:46:40 -0400
Subject: [PATCH] Correctly handle rapid disconnects. Fixes #31

---
 .../proxy/connection/MinecraftConnection.java     | 15 +++++++++------
 .../backend/BackendPlaySessionHandler.java        | 14 ++++++++++++++
 .../proxy/connection/client/ConnectedPlayer.java  |  1 -
 3 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java b/proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java
index 6d9738414..a87c95e40 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java
@@ -104,18 +104,21 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     }
 
     public void write(Object msg) {
-        ensureOpen();
-        channel.writeAndFlush(msg, channel.voidPromise());
+        if (channel.isActive()) {
+            channel.writeAndFlush(msg, channel.voidPromise());
+        }
     }
 
     public void delayedWrite(Object msg) {
-        ensureOpen();
-        channel.write(msg, channel.voidPromise());
+        if (channel.isActive()) {
+            channel.write(msg, channel.voidPromise());
+        }
     }
 
     public void flush() {
-        ensureOpen();
-        channel.flush();
+        if (channel.isActive()) {
+            channel.flush();
+        }
     }
 
     public void closeWith(Object msg) {
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java b/proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java
index bbf407952..b8975a0b3 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java
@@ -18,6 +18,13 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
 
     @Override
     public void handle(MinecraftPacket packet) {
+        if (!connection.getProxyPlayer().isActive()) {
+            // Connection was left open accidentally. Close it so as to avoid "You logged in from another location"
+            // errors.
+            connection.getMinecraftConnection().close();
+            return;
+        }
+
         ClientPlaySessionHandler playerHandler =
                 (ClientPlaySessionHandler) connection.getProxyPlayer().getConnection().getSessionHandler();
         if (packet instanceof KeepAlive) {
@@ -69,6 +76,13 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
 
     @Override
     public void handleUnknown(ByteBuf buf) {
+        if (!connection.getProxyPlayer().isActive()) {
+            // Connection was left open accidentally. Close it so as to avoid "You logged in from another location"
+            // errors.
+            connection.getMinecraftConnection().close();
+            return;
+        }
+
         ClientPlaySessionHandler playerHandler =
                 (ClientPlaySessionHandler) connection.getProxyPlayer().getConnection().getSessionHandler();
         ByteBuf remapped = playerHandler.getIdRemapper().remap(buf, ProtocolConstants.Direction.CLIENTBOUND);
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java b/proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java
index 2cf2b887f..bf4f05916 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java
@@ -132,7 +132,6 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
         String error = ThrowableUtils.briefDescription(throwable);
         String userMessage;
         if (connectedServer != null && connectedServer.getServerInfo().equals(info)) {
-            logger.error("{}: exception occurred in connection to {}", this, info.getName(), throwable);
             userMessage = "Exception in server " + info.getName();
         } else {
             logger.error("{}: unable to connect to server {}", this, info.getName(), throwable);