Check email addresses through SMTP

SmtpEmailChecker.php

<?php

class SmtpEmailChecker
{

	protected $from;

	protected $code;

	/**
	 * @return mixed
	 */
	public function getCode()
	{
		return $this->code;
	}


	public function __construct($from)
	{
		$this->from = $from;
	}

	public function check($email)
	{
		if (strpos($email, '@') === false) {
			return false;
		}

		$mxHosts = [];
		$weight = [];

		getmxrr(explode('@', $email)[1], $mxHosts, $weight);

		$mxHosts = array_combine($weight, $mxHosts);

		ksort($mxHosts);

		$socket = false;

		foreach ($mxHosts as $mxHost) {

			try {

				$socket = fsockopen($mxHost, 25, $errno, $errstr, 5);
				stream_set_timeout($socket, 5);
			}
			catch (Exception $e) {

			}

			if ($socket)
			{
				break;
			}
		}

		if ($socket) {

			try {

				$reply = fread($socket, 2082);

				$helloCode = intval(substr($reply, 0, 3));

				if ($helloCode != 220) {
					$this->code = 0;

					return false;
				}
				else {

					fwrite($socket, "HELO " . gethostname() . "\r\n");

					fread($socket, 2082);

					fwrite($socket, "MAIL FROM: <" . $this->from . ">" . "\r\n");

					fread($socket, 2082);

					fwrite($socket, "RCPT TO: <" . $email . ">" . "\r\n");

					$response = fread($socket, 2082);

					fwrite($socket, "quit" . "\r\n");

					fread($socket, 2082);

					fclose($socket);

					$code = intval(substr($response, 0, 3));

					$this->code = $code;

					switch ($code) {
						case 250:
							return true;
						case 451:
							return true;
						case 550:
							return false;
						default:
							return false;
					}

				}
			}
			catch (Exception $e) {
				error_log($e->getMessage());
			}
		}

		$this->code = 0;
		return false;
	}
}