/**
* Reads the last line from a socket connection
* @param resource $conn A reference to connection handler
* @param string $line A reference to read line
* @return boolean TRUE on success or FALSE on error
*/
function readLastLineConn(&$conn, &$line)
{
$result = false;
$line = '';
if (!empty($conn) && is_resource($conn) && !feof($conn)) {
while (PCPIN_TCP::readLineConn($conn, $line)) {
if ($line == '') {
break;
} elseif (substr($line, 3, 1) == ' ') {
$result = true;
break;
}
}
}
return $result;
}
/**
* E-Mail address validator
* @param string $email E-Mail address
* @param int $level Validation level
* Value Description
* 0 No validation
* 1 Well-formness check
* 2 Hostname (or DNS record, if Hostname failed) resolution
* 3 Recipient account availability check (violates RFC, use with care!)
* @return boolean TRUE if email address is valid or FALSE if not
*/
function checkEmail($email = '', $level = 1)
{
$valid = false;
$email = trim($email);
if ($email != '') {
$valid = true;
if ($level >= 1) {
// Well-formness check
$valid = (bool) preg_match('/^([a-zA-Z0-9]+[\\._-]?)+[a-zA-Z0-9]+@(((([a-zA-Z0-9]+-?)+[a-zA-Z0-9]+)|([a-zA-Z0-9]{2,}))+\\.)+[a-zA-Z]{2,4}$/', $email);
if ($valid && $level >= 2) {
// Hostname (or DNS record, if Hostname failed) resolution
$hostname = strtolower(substr($email, strpos($email, '@') + 1));
$host = gethostbyname($hostname);
if ($host == $hostname) {
$host = '';
}
if ($host == '') {
// Hostname resolutiion failed
// Check DNS record
$valid = PCPIN_TCP::checkDNS_record($hostname);
} else {
$valid = true;
}
if ($valid && $level >= 3) {
// Recipient account availability check
$valid = false;
// Get MX records
$ips = PCPIN_TCP::getMXRecords($hostname);
if (empty($ips)) {
// No MX records found. Using Hostname.
$ips = gethostbynamel($hostname);
}
// Trying to open connection
$conn = false;
foreach ($ips as $ip) {
$conn = null;
$errno = null;
$errstr = null;
if (PCPIN_TCP::connectHost($conn, $errno, $errstr, $ip, 10)) {
// Connection opened
break;
}
}
$sender_host = !empty($_SERVER['HTTP_HOST']) && $_SERVER['HTTP_HOST'] != '' ? $_SERVER['HTTP_HOST'] : 'UNKNOWN.HOST';
if (!empty($conn)) {
$line = '';
// Gest SMTP server signature
if (PCPIN_TCP::readLastLineConn($conn, $line)) {
if (220 === PCPIN_TCP::getStatus($line)) {
// Send 'HELO' command
if (PCPIN_TCP::writeDataConn($conn, "HELO {$sender_host}\r\n")) {
// Get an answer
if (PCPIN_TCP::readLastLineConn($conn, $line)) {
// Check response status
if (250 === PCPIN_TCP::getStatus($line)) {
// Start email conversation
if (PCPIN_TCP::writeDataConn($conn, "MAIL FROM: <test@{$sender_host}>\r\n")) {
// Get an answer
if (PCPIN_TCP::readLastLineConn($conn, $line)) {
// Check response status
if (250 === PCPIN_TCP::getStatus($line)) {
// Specify recipient mailbox
if (PCPIN_TCP::writeDataConn($conn, "RCPT TO: <" . $email . ">\r\n")) {
// Get an answer
if (PCPIN_TCP::readLastLineConn($conn, $line)) {
// Status 250: mailbox exists :)
$valid = 250 === PCPIN_TCP::getStatus($line);
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
return $valid;
}
