weird-server.php

<?php

class Server
{
	public $master;
	public $read = [];
	public $write = [];
	public $writeBuf = [];
	
	public function listen($address)
	{
		$this->master = stream_socket_server($address);
		stream_set_blocking($this->master, 0);
		$this->read[] = $this->master;
		
		$this->loop();
	}
	
	public function loop()
	{
		while (true) {
			$readable = $this->read ?: null;
			$writable = $this->write ?: null;
			$except = null;
			
			if (!stream_select($readable, $writeable, $except, 1)) {
				continue;
			}
			
			if ($readable) {
				$this->processReadableStreams($readable);
			}

			if ($writable) {
				$this->processWritableStreams($writable);
			}
		}
	}
	
	public function processReadableStreams($readable)
	{
		foreach ($readable as $stream) {
			if ($this->master === $stream) {
				$this->acceptConnection($stream);
			} else {
				$this->processIncomingData($stream);
			}
		}
	}
	
	public function acceptConnection($master)
	{
		$conn = stream_socket_accept($master, 0);
		stream_set_blocking($conn, 0);
		$this->read[] = $conn;
	}
	
	public function processIncomingData($conn)
	{
		$data = fread($conn, 1024);
		if ('' === $data) {
			fclose($conn);
			
			$index = array_search($conn, $this->read);
			unset($this->read[$index]);
			
			$index = array_search($conn, $this->write);
			if (false !== $index) {
				unset($this->write[$index]);
			}
		} else {
			$this->enqueueData($conn, $data);
		}
	}
	
	public function enqueueData($conn, $data)
	{
		$id = (int) $conn;
		if (!isset($this->writeBuf[$id])) {
			$this->writeBuf[$id] = '';
		}
		$this->writeBuf[$id] .= $data;
		$this->write[] = $conn;
	}

	public function processWritableStreams($writable)
	{
		foreach ($writable as $stream) {
			$this->writeOutgoingData($stream);
		}
	}
	
	public function writeOutgoingData($conn)
	{
		$id = (int) $conn;
		$data = $this->writeBuf[$id];
		$written = fwrite($conn, $data);
		$this->writeBuf[$id] = (string) substr($this->writeBuf[$id], $written);

		if ('' === $this->writeBuf[$id]) {
			$index = array_search($conn, $this->write);
			unset($this->write[$index]);
		}
	}
}

$server = new Server();
$server->listen('tcp://127.0.0.1:1337');