rough work for CommandOutputPacket, no idea if it works

src/pocketmine/network/mcpe/protocol/CommandOutputPacket.php

@@ -26,16 +26,73 @@ namespace pocketmine\network\mcpe\protocol;
 #include <rules/DataPacket.h>
 
 use pocketmine\network\mcpe\NetworkSession;
+use pocketmine\network\mcpe\protocol\types\CommandOriginData;
+use pocketmine\network\mcpe\protocol\types\CommandOutputMessage;
 
 class CommandOutputPacket extends DataPacket{
 	const NETWORK_ID = ProtocolInfo::COMMAND_OUTPUT_PACKET;
 
+	/** @var CommandOriginData */
+	public $originData;
+	/** @var int */
+	public $outputType;
+	/** @var int */
+	public $successCount;
+	/** @var CommandOutputMessage[] */
+	public $messages = [];
+	/** @var string */
+	public $unknownString;
+
 	protected function decodePayload(){
-		//TODO
+		$this->originData = $this->getCommandOriginData();
+		$this->outputType = $this->getByte();
+		$this->successCount = $this->getUnsignedVarInt();
+
+		for($i = 0, $size = $this->getUnsignedVarInt(); $i < $size; ++$i){
+			$this->messages[] = $this->getCommandMessage();
+		}
+
+		if($this->outputType === 4){
+			$this->unknownString = $this->getString();
+		}
+	}
+
+	protected function getCommandMessage() : CommandOutputMessage{
+		$message = new CommandOutputMessage();
+
+		$message->isInternal = $this->getBool();
+		$message->messageId = $this->getString();
+
+		for($i = 0, $size = $this->getUnsignedVarInt(); $i < $size; ++$i){
+			$message->parameters[] = $this->getString();
+		}
+
+		return $message;
 	}
 
 	protected function encodePayload(){
-		//TODO
+		$this->putCommandOriginData($this->originData);
+		$this->putByte($this->outputType);
+		$this->putUnsignedVarInt($this->successCount);
+
+		$this->putUnsignedVarInt(count($this->messages));
+		foreach($this->messages as $message){
+			$this->putCommandMessage($message);
+		}
+
+		if($this->outputType === 4){
+			$this->putString($this->unknownString);
+		}
+	}
+
+	protected function putCommandMessage(CommandOutputMessage $message){
+		$this->putBool($message->isInternal);
+		$this->putString($message->messageId);
+
+		$this->putUnsignedVarInt(count($message->parameters));
+		foreach($message->parameters as $parameter){
+			$this->putString($parameter);
+		}
 	}
 
 	public function handle(NetworkSession $session) : bool{

src/pocketmine/network/mcpe/protocol/types/CommandOutputMessage.php

@@ -0,0 +1,34 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\network\mcpe\protocol\types;
+
+class CommandOutputMessage{
+	/** @var bool */
+	public $isInternal;
+	/** @var string */
+	public $messageId;
+	/** @var string[] */
+	public $parameters = [];
+
+}