Pocketmine-mp: Provide a way to bypass accepted skin sizes

[MCPE-PC]

Description

I would suggest one of these

• Making Skin class not final
• Changing ACCEPTED_SKIN_SIZES into a variable
• Provide a way to bypass accepted skin sizes

Justification

When I tried to set the skin of an entity, an exception [Server thread/CRITICAL]: InvalidArgumentException: "Invalid skin data size 32769 bytes (allowed sizes: 8192, 16384, 65536)" (EXCEPTION) occurred because the skin size changed due to the rotation of the geometry. I needed a way to pass the skin size limitation.

Alternative methods

• 
  
  1. Define a hacky class
     
     I tried to make a clone of Skin class like:
  
  

<?php

/*
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 */

declare(strict_types=1);

namespace your\plugin;

use function implode;
use function in_array;
use function json_decode;
use function json_encode;
use function json_last_error_msg;
use function strlen;

class DynamicSkin {
    protected static $acceptedSkinSizes = [
        64 * 32 * 4,
        64 * 64 * 4,
        128 * 128 * 4
    ];

    /** @var string */
    private $skinId;
    /** @var string */
    private $skinData;
    /** @var string */
    private $capeData;
    /** @var string */
    private $geometryName;
    /** @var string */
    private $geometryData;

    public function __construct(string $skinId, string $skinData, string $capeData = "", string $geometryName = "", string $geometryData = ""){
        if($skinId === ""){
            throw new \InvalidArgumentException("Skin ID must not be empty");
        }
        $len = strlen($skinData);
        if(!in_array($len, self::$acceptedSkinSizes, true)){
            throw new \InvalidArgumentException("Invalid skin data size $len bytes (allowed sizes: " . implode(", ", self::$acceptedSkinSizes) . ")");
        }
        if($capeData !== "" and strlen($capeData) !== 8192){
            throw new \InvalidArgumentException("Invalid cape data size " . strlen($capeData) . " bytes (must be exactly 8192 bytes)");
        }

        if($geometryData !== ""){
            $decodedGeometry = json_decode($geometryData);
            if($decodedGeometry === false){
                throw new \InvalidArgumentException("Invalid geometry data (" . json_last_error_msg() . ")");
            }

            /*
             * Hack to cut down on network overhead due to skins, by un-pretty-printing geometry JSON.
             *
             * Mojang, some stupid reason, send every single model for every single skin in the selected skin-pack.
             * Not only that, they are pretty-printed.
             * TODO: find out what model crap can be safely dropped from the packet (unless it gets fixed first)
             */
            $geometryData = json_encode($decodedGeometry);
        }

        $this->skinId = $skinId;
        $this->skinData = $skinData;
        $this->capeData = $capeData;
        $this->geometryName = $geometryName;
        $this->geometryData = $geometryData;
    }

    public static function addAcceptedSkinSize(int $byte) : bool {
        if (in_array($byte, self::$acceptedSkinSizes)) {
            return false;
        }

        self::$acceptedSkinSizes[] = $byte;
        return true;
    }

    /**
     * @return string
     */
    public function getSkinId() : string{
        return $this->skinId;
    }

    /**
     * @return string
     */
    public function getSkinData() : string{
        return $this->skinData;
    }

    /**
     * @return string
     */
    public function getCapeData() : string{
        return $this->capeData;
    }

    /**
     * @return string
     */
    public function getGeometryName() : string{
        return $this->geometryName;
    }

    /**
     * @return string
     */
    public function getGeometryData() : string{
        return $this->geometryData;
    }
}

And a problem happens when a player joins after the skin has changed
[Server thread/CRITICAL]: TypeError: "Argument 4 passed to pocketmine\network\mcpe\protocol\types\PlayerListEntry::createAdditionEntry() must be an instance of pocketmine\entity\Skin, instance of your\plugin\DynamicSkin given...

• 
  
  1. Modify PMMP code directly
     
     I would simply remove the final keyword of Skin class and extend it on the plugin
  
  

[dktapps]

These sizes are the only sizes accepted by the game, regardless of geometry.