Simpler HTTP Socket server in PHP (Apache, no modules)

PSocket.php

<?php

declare(strict_types=1);

$input = fopen("php://input");

class HTTPSocketServer {
	public ?callable $onData = null;
	private bool $serverStarted = false;
	
	public function __construct(callable $onNewClient, callable $onLeaveClient, ?callable $onData = null)
	{
		if($_SERVER['REQUEST_METHOD'] !== 'GET')
		{
			http_response_code(405);
			exit();
		};
		
		if(
		
		$onNewClient();
		register_shutdown_function($onLeaveClient);
		$this->$onData = $onData;
	};
	
	public function _onData()
	{
		if(!$this->$serverStarted)
		{
			this->$serverStarted = true;
			new EvTimer(0.005, 1, $this->_onData);
		};
	
		if(isset($this->$onData)) $this->$onData(fread($input));
	};
};