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SMTP.php (47285B)


      1 <?php
      2 
      3 /**
      4  * PHPMailer RFC821 SMTP email transport class.
      5  * PHP Version 5.5.
      6  *
      7  * @see       https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
      8  *
      9  * @author    Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
     10  * @author    Jim Jagielski (jimjag) <jimjag@gmail.com>
     11  * @author    Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
     12  * @author    Brent R. Matzelle (original founder)
     13  * @copyright 2012 - 2020 Marcus Bointon
     14  * @copyright 2010 - 2012 Jim Jagielski
     15  * @copyright 2004 - 2009 Andy Prevost
     16  * @license   http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
     17  * @note      This program is distributed in the hope that it will be useful - WITHOUT
     18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     19  * FITNESS FOR A PARTICULAR PURPOSE.
     20  */
     21 
     22 namespace PHPMailer\PHPMailer;
     23 
     24 /**
     25  * PHPMailer RFC821 SMTP email transport class.
     26  * Implements RFC 821 SMTP commands and provides some utility methods for sending mail to an SMTP server.
     27  *
     28  * @author Chris Ryan
     29  * @author Marcus Bointon <phpmailer@synchromedia.co.uk>
     30  */
     31 class SMTP
     32 {
     33     /**
     34      * The PHPMailer SMTP version number.
     35      *
     36      * @var string
     37      */
     38     const VERSION = '6.5.0';
     39 
     40     /**
     41      * SMTP line break constant.
     42      *
     43      * @var string
     44      */
     45     const LE = "\r\n";
     46 
     47     /**
     48      * The SMTP port to use if one is not specified.
     49      *
     50      * @var int
     51      */
     52     const DEFAULT_PORT = 25;
     53 
     54     /**
     55      * The maximum line length allowed by RFC 5321 section 4.5.3.1.6,
     56      * *excluding* a trailing CRLF break.
     57      *
     58      * @see https://tools.ietf.org/html/rfc5321#section-4.5.3.1.6
     59      *
     60      * @var int
     61      */
     62     const MAX_LINE_LENGTH = 998;
     63 
     64     /**
     65      * The maximum line length allowed for replies in RFC 5321 section 4.5.3.1.5,
     66      * *including* a trailing CRLF line break.
     67      *
     68      * @see https://tools.ietf.org/html/rfc5321#section-4.5.3.1.5
     69      *
     70      * @var int
     71      */
     72     const MAX_REPLY_LENGTH = 512;
     73 
     74     /**
     75      * Debug level for no output.
     76      *
     77      * @var int
     78      */
     79     const DEBUG_OFF = 0;
     80 
     81     /**
     82      * Debug level to show client -> server messages.
     83      *
     84      * @var int
     85      */
     86     const DEBUG_CLIENT = 1;
     87 
     88     /**
     89      * Debug level to show client -> server and server -> client messages.
     90      *
     91      * @var int
     92      */
     93     const DEBUG_SERVER = 2;
     94 
     95     /**
     96      * Debug level to show connection status, client -> server and server -> client messages.
     97      *
     98      * @var int
     99      */
    100     const DEBUG_CONNECTION = 3;
    101 
    102     /**
    103      * Debug level to show all messages.
    104      *
    105      * @var int
    106      */
    107     const DEBUG_LOWLEVEL = 4;
    108 
    109     /**
    110      * Debug output level.
    111      * Options:
    112      * * self::DEBUG_OFF (`0`) No debug output, default
    113      * * self::DEBUG_CLIENT (`1`) Client commands
    114      * * self::DEBUG_SERVER (`2`) Client commands and server responses
    115      * * self::DEBUG_CONNECTION (`3`) As DEBUG_SERVER plus connection status
    116      * * self::DEBUG_LOWLEVEL (`4`) Low-level data output, all messages.
    117      *
    118      * @var int
    119      */
    120     public $do_debug = self::DEBUG_OFF;
    121 
    122     /**
    123      * How to handle debug output.
    124      * Options:
    125      * * `echo` Output plain-text as-is, appropriate for CLI
    126      * * `html` Output escaped, line breaks converted to `<br>`, appropriate for browser output
    127      * * `error_log` Output to error log as configured in php.ini
    128      * Alternatively, you can provide a callable expecting two params: a message string and the debug level:
    129      *
    130      * ```php
    131      * $smtp->Debugoutput = function($str, $level) {echo "debug level $level; message: $str";};
    132      * ```
    133      *
    134      * Alternatively, you can pass in an instance of a PSR-3 compatible logger, though only `debug`
    135      * level output is used:
    136      *
    137      * ```php
    138      * $mail->Debugoutput = new myPsr3Logger;
    139      * ```
    140      *
    141      * @var string|callable|\Psr\Log\LoggerInterface
    142      */
    143     public $Debugoutput = 'echo';
    144 
    145     /**
    146      * Whether to use VERP.
    147      *
    148      * @see http://en.wikipedia.org/wiki/Variable_envelope_return_path
    149      * @see http://www.postfix.org/VERP_README.html Info on VERP
    150      *
    151      * @var bool
    152      */
    153     public $do_verp = false;
    154 
    155     /**
    156      * The timeout value for connection, in seconds.
    157      * Default of 5 minutes (300sec) is from RFC2821 section 4.5.3.2.
    158      * This needs to be quite high to function correctly with hosts using greetdelay as an anti-spam measure.
    159      *
    160      * @see http://tools.ietf.org/html/rfc2821#section-4.5.3.2
    161      *
    162      * @var int
    163      */
    164     public $Timeout = 300;
    165 
    166     /**
    167      * How long to wait for commands to complete, in seconds.
    168      * Default of 5 minutes (300sec) is from RFC2821 section 4.5.3.2.
    169      *
    170      * @var int
    171      */
    172     public $Timelimit = 300;
    173 
    174     /**
    175      * Patterns to extract an SMTP transaction id from reply to a DATA command.
    176      * The first capture group in each regex will be used as the ID.
    177      * MS ESMTP returns the message ID, which may not be correct for internal tracking.
    178      *
    179      * @var string[]
    180      */
    181     protected $smtp_transaction_id_patterns = [
    182         'exim' => '/[\d]{3} OK id=(.*)/',
    183         'sendmail' => '/[\d]{3} 2.0.0 (.*) Message/',
    184         'postfix' => '/[\d]{3} 2.0.0 Ok: queued as (.*)/',
    185         'Microsoft_ESMTP' => '/[0-9]{3} 2.[\d].0 (.*)@(?:.*) Queued mail for delivery/',
    186         'Amazon_SES' => '/[\d]{3} Ok (.*)/',
    187         'SendGrid' => '/[\d]{3} Ok: queued as (.*)/',
    188         'CampaignMonitor' => '/[\d]{3} 2.0.0 OK:([a-zA-Z\d]{48})/',
    189         'Haraka' => '/[\d]{3} Message Queued \((.*)\)/',
    190     ];
    191 
    192     /**
    193      * The last transaction ID issued in response to a DATA command,
    194      * if one was detected.
    195      *
    196      * @var string|bool|null
    197      */
    198     protected $last_smtp_transaction_id;
    199 
    200     /**
    201      * The socket for the server connection.
    202      *
    203      * @var ?resource
    204      */
    205     protected $smtp_conn;
    206 
    207     /**
    208      * Error information, if any, for the last SMTP command.
    209      *
    210      * @var array
    211      */
    212     protected $error = [
    213         'error' => '',
    214         'detail' => '',
    215         'smtp_code' => '',
    216         'smtp_code_ex' => '',
    217     ];
    218 
    219     /**
    220      * The reply the server sent to us for HELO.
    221      * If null, no HELO string has yet been received.
    222      *
    223      * @var string|null
    224      */
    225     protected $helo_rply;
    226 
    227     /**
    228      * The set of SMTP extensions sent in reply to EHLO command.
    229      * Indexes of the array are extension names.
    230      * Value at index 'HELO' or 'EHLO' (according to command that was sent)
    231      * represents the server name. In case of HELO it is the only element of the array.
    232      * Other values can be boolean TRUE or an array containing extension options.
    233      * If null, no HELO/EHLO string has yet been received.
    234      *
    235      * @var array|null
    236      */
    237     protected $server_caps;
    238 
    239     /**
    240      * The most recent reply received from the server.
    241      *
    242      * @var string
    243      */
    244     protected $last_reply = '';
    245 
    246     /**
    247      * Output debugging info via a user-selected method.
    248      *
    249      * @param string $str   Debug string to output
    250      * @param int    $level The debug level of this message; see DEBUG_* constants
    251      *
    252      * @see SMTP::$Debugoutput
    253      * @see SMTP::$do_debug
    254      */
    255     protected function edebug($str, $level = 0)
    256     {
    257         if ($level > $this->do_debug) {
    258             return;
    259         }
    260         //Is this a PSR-3 logger?
    261         if ($this->Debugoutput instanceof \Psr\Log\LoggerInterface) {
    262             $this->Debugoutput->debug($str);
    263 
    264             return;
    265         }
    266         //Avoid clash with built-in function names
    267         if (is_callable($this->Debugoutput) && !in_array($this->Debugoutput, ['error_log', 'html', 'echo'])) {
    268             call_user_func($this->Debugoutput, $str, $level);
    269 
    270             return;
    271         }
    272         switch ($this->Debugoutput) {
    273             case 'error_log':
    274                 //Don't output, just log
    275                 error_log($str);
    276                 break;
    277             case 'html':
    278                 //Cleans up output a bit for a better looking, HTML-safe output
    279                 echo gmdate('Y-m-d H:i:s'), ' ', htmlentities(
    280                     preg_replace('/[\r\n]+/', '', $str),
    281                     ENT_QUOTES,
    282                     'UTF-8'
    283                 ), "<br>\n";
    284                 break;
    285             case 'echo':
    286             default:
    287                 //Normalize line breaks
    288                 $str = preg_replace('/\r\n|\r/m', "\n", $str);
    289                 echo gmdate('Y-m-d H:i:s'),
    290                 "\t",
    291                     //Trim trailing space
    292                 trim(
    293                     //Indent for readability, except for trailing break
    294                     str_replace(
    295                         "\n",
    296                         "\n                   \t                  ",
    297                         trim($str)
    298                     )
    299                 ),
    300                 "\n";
    301         }
    302     }
    303 
    304     /**
    305      * Connect to an SMTP server.
    306      *
    307      * @param string $host    SMTP server IP or host name
    308      * @param int    $port    The port number to connect to
    309      * @param int    $timeout How long to wait for the connection to open
    310      * @param array  $options An array of options for stream_context_create()
    311      *
    312      * @return bool
    313      */
    314     public function connect($host, $port = null, $timeout = 30, $options = [])
    315     {
    316         //Clear errors to avoid confusion
    317         $this->setError('');
    318         //Make sure we are __not__ connected
    319         if ($this->connected()) {
    320             //Already connected, generate error
    321             $this->setError('Already connected to a server');
    322 
    323             return false;
    324         }
    325         if (empty($port)) {
    326             $port = self::DEFAULT_PORT;
    327         }
    328         //Connect to the SMTP server
    329         $this->edebug(
    330             "Connection: opening to $host:$port, timeout=$timeout, options=" .
    331             (count($options) > 0 ? var_export($options, true) : 'array()'),
    332             self::DEBUG_CONNECTION
    333         );
    334 
    335         $this->smtp_conn = $this->getSMTPConnection($host, $port, $timeout, $options);
    336 
    337         if ($this->smtp_conn === false) {
    338             //Error info already set inside `getSMTPConnection()`
    339             return false;
    340         }
    341 
    342         $this->edebug('Connection: opened', self::DEBUG_CONNECTION);
    343 
    344         //Get any announcement
    345         $this->last_reply = $this->get_lines();
    346         $this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER);
    347         $responseCode = (int)substr($this->last_reply, 0, 3);
    348         if ($responseCode === 220) {
    349             return true;
    350         }
    351         //Anything other than a 220 response means something went wrong
    352         //RFC 5321 says the server will wait for us to send a QUIT in response to a 554 error
    353         //https://tools.ietf.org/html/rfc5321#section-3.1
    354         if ($responseCode === 554) {
    355             $this->quit();
    356         }
    357         //This will handle 421 responses which may not wait for a QUIT (e.g. if the server is being shut down)
    358         $this->edebug('Connection: closing due to error', self::DEBUG_CONNECTION);
    359         $this->close();
    360         return false;
    361     }
    362 
    363     /**
    364      * Create connection to the SMTP server.
    365      *
    366      * @param string $host    SMTP server IP or host name
    367      * @param int    $port    The port number to connect to
    368      * @param int    $timeout How long to wait for the connection to open
    369      * @param array  $options An array of options for stream_context_create()
    370      *
    371      * @return false|resource
    372      */
    373     protected function getSMTPConnection($host, $port = null, $timeout = 30, $options = [])
    374     {
    375         static $streamok;
    376         //This is enabled by default since 5.0.0 but some providers disable it
    377         //Check this once and cache the result
    378         if (null === $streamok) {
    379             $streamok = function_exists('stream_socket_client');
    380         }
    381 
    382         $errno = 0;
    383         $errstr = '';
    384         if ($streamok) {
    385             $socket_context = stream_context_create($options);
    386             set_error_handler([$this, 'errorHandler']);
    387             $connection = stream_socket_client(
    388                 $host . ':' . $port,
    389                 $errno,
    390                 $errstr,
    391                 $timeout,
    392                 STREAM_CLIENT_CONNECT,
    393                 $socket_context
    394             );
    395             restore_error_handler();
    396         } else {
    397             //Fall back to fsockopen which should work in more places, but is missing some features
    398             $this->edebug(
    399                 'Connection: stream_socket_client not available, falling back to fsockopen',
    400                 self::DEBUG_CONNECTION
    401             );
    402             set_error_handler([$this, 'errorHandler']);
    403             $connection = fsockopen(
    404                 $host,
    405                 $port,
    406                 $errno,
    407                 $errstr,
    408                 $timeout
    409             );
    410             restore_error_handler();
    411         }
    412 
    413         //Verify we connected properly
    414         if (!is_resource($connection)) {
    415             $this->setError(
    416                 'Failed to connect to server',
    417                 '',
    418                 (string) $errno,
    419                 $errstr
    420             );
    421             $this->edebug(
    422                 'SMTP ERROR: ' . $this->error['error']
    423                 . ": $errstr ($errno)",
    424                 self::DEBUG_CLIENT
    425             );
    426 
    427             return false;
    428         }
    429 
    430         //SMTP server can take longer to respond, give longer timeout for first read
    431         //Windows does not have support for this timeout function
    432         if (strpos(PHP_OS, 'WIN') !== 0) {
    433             $max = (int)ini_get('max_execution_time');
    434             //Don't bother if unlimited, or if set_time_limit is disabled
    435             if (0 !== $max && $timeout > $max && strpos(ini_get('disable_functions'), 'set_time_limit') === false) {
    436                 @set_time_limit($timeout);
    437             }
    438             stream_set_timeout($connection, $timeout, 0);
    439         }
    440 
    441         return $connection;
    442     }
    443 
    444     /**
    445      * Initiate a TLS (encrypted) session.
    446      *
    447      * @return bool
    448      */
    449     public function startTLS()
    450     {
    451         if (!$this->sendCommand('STARTTLS', 'STARTTLS', 220)) {
    452             return false;
    453         }
    454 
    455         //Allow the best TLS version(s) we can
    456         $crypto_method = STREAM_CRYPTO_METHOD_TLS_CLIENT;
    457 
    458         //PHP 5.6.7 dropped inclusion of TLS 1.1 and 1.2 in STREAM_CRYPTO_METHOD_TLS_CLIENT
    459         //so add them back in manually if we can
    460         if (defined('STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT')) {
    461             $crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT;
    462             $crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT;
    463         }
    464 
    465         //Begin encrypted connection
    466         set_error_handler([$this, 'errorHandler']);
    467         $crypto_ok = stream_socket_enable_crypto(
    468             $this->smtp_conn,
    469             true,
    470             $crypto_method
    471         );
    472         restore_error_handler();
    473 
    474         return (bool) $crypto_ok;
    475     }
    476 
    477     /**
    478      * Perform SMTP authentication.
    479      * Must be run after hello().
    480      *
    481      * @see    hello()
    482      *
    483      * @param string $username The user name
    484      * @param string $password The password
    485      * @param string $authtype The auth type (CRAM-MD5, PLAIN, LOGIN, XOAUTH2)
    486      * @param OAuth  $OAuth    An optional OAuth instance for XOAUTH2 authentication
    487      *
    488      * @return bool True if successfully authenticated
    489      */
    490     public function authenticate(
    491         $username,
    492         $password,
    493         $authtype = null,
    494         $OAuth = null
    495     ) {
    496         if (!$this->server_caps) {
    497             $this->setError('Authentication is not allowed before HELO/EHLO');
    498 
    499             return false;
    500         }
    501 
    502         if (array_key_exists('EHLO', $this->server_caps)) {
    503             //SMTP extensions are available; try to find a proper authentication method
    504             if (!array_key_exists('AUTH', $this->server_caps)) {
    505                 $this->setError('Authentication is not allowed at this stage');
    506                 //'at this stage' means that auth may be allowed after the stage changes
    507                 //e.g. after STARTTLS
    508 
    509                 return false;
    510             }
    511 
    512             $this->edebug('Auth method requested: ' . ($authtype ?: 'UNSPECIFIED'), self::DEBUG_LOWLEVEL);
    513             $this->edebug(
    514                 'Auth methods available on the server: ' . implode(',', $this->server_caps['AUTH']),
    515                 self::DEBUG_LOWLEVEL
    516             );
    517 
    518             //If we have requested a specific auth type, check the server supports it before trying others
    519             if (null !== $authtype && !in_array($authtype, $this->server_caps['AUTH'], true)) {
    520                 $this->edebug('Requested auth method not available: ' . $authtype, self::DEBUG_LOWLEVEL);
    521                 $authtype = null;
    522             }
    523 
    524             if (empty($authtype)) {
    525                 //If no auth mechanism is specified, attempt to use these, in this order
    526                 //Try CRAM-MD5 first as it's more secure than the others
    527                 foreach (['CRAM-MD5', 'LOGIN', 'PLAIN', 'XOAUTH2'] as $method) {
    528                     if (in_array($method, $this->server_caps['AUTH'], true)) {
    529                         $authtype = $method;
    530                         break;
    531                     }
    532                 }
    533                 if (empty($authtype)) {
    534                     $this->setError('No supported authentication methods found');
    535 
    536                     return false;
    537                 }
    538                 $this->edebug('Auth method selected: ' . $authtype, self::DEBUG_LOWLEVEL);
    539             }
    540 
    541             if (!in_array($authtype, $this->server_caps['AUTH'], true)) {
    542                 $this->setError("The requested authentication method \"$authtype\" is not supported by the server");
    543 
    544                 return false;
    545             }
    546         } elseif (empty($authtype)) {
    547             $authtype = 'LOGIN';
    548         }
    549         switch ($authtype) {
    550             case 'PLAIN':
    551                 //Start authentication
    552                 if (!$this->sendCommand('AUTH', 'AUTH PLAIN', 334)) {
    553                     return false;
    554                 }
    555                 //Send encoded username and password
    556                 if (
    557                     //Format from https://tools.ietf.org/html/rfc4616#section-2
    558                     //We skip the first field (it's forgery), so the string starts with a null byte
    559                     !$this->sendCommand(
    560                         'User & Password',
    561                         base64_encode("\0" . $username . "\0" . $password),
    562                         235
    563                     )
    564                 ) {
    565                     return false;
    566                 }
    567                 break;
    568             case 'LOGIN':
    569                 //Start authentication
    570                 if (!$this->sendCommand('AUTH', 'AUTH LOGIN', 334)) {
    571                     return false;
    572                 }
    573                 if (!$this->sendCommand('Username', base64_encode($username), 334)) {
    574                     return false;
    575                 }
    576                 if (!$this->sendCommand('Password', base64_encode($password), 235)) {
    577                     return false;
    578                 }
    579                 break;
    580             case 'CRAM-MD5':
    581                 //Start authentication
    582                 if (!$this->sendCommand('AUTH CRAM-MD5', 'AUTH CRAM-MD5', 334)) {
    583                     return false;
    584                 }
    585                 //Get the challenge
    586                 $challenge = base64_decode(substr($this->last_reply, 4));
    587 
    588                 //Build the response
    589                 $response = $username . ' ' . $this->hmac($challenge, $password);
    590 
    591                 //send encoded credentials
    592                 return $this->sendCommand('Username', base64_encode($response), 235);
    593             case 'XOAUTH2':
    594                 //The OAuth instance must be set up prior to requesting auth.
    595                 if (null === $OAuth) {
    596                     return false;
    597                 }
    598                 $oauth = $OAuth->getOauth64();
    599 
    600                 //Start authentication
    601                 if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2 ' . $oauth, 235)) {
    602                     return false;
    603                 }
    604                 break;
    605             default:
    606                 $this->setError("Authentication method \"$authtype\" is not supported");
    607 
    608                 return false;
    609         }
    610 
    611         return true;
    612     }
    613 
    614     /**
    615      * Calculate an MD5 HMAC hash.
    616      * Works like hash_hmac('md5', $data, $key)
    617      * in case that function is not available.
    618      *
    619      * @param string $data The data to hash
    620      * @param string $key  The key to hash with
    621      *
    622      * @return string
    623      */
    624     protected function hmac($data, $key)
    625     {
    626         if (function_exists('hash_hmac')) {
    627             return hash_hmac('md5', $data, $key);
    628         }
    629 
    630         //The following borrowed from
    631         //http://php.net/manual/en/function.mhash.php#27225
    632 
    633         //RFC 2104 HMAC implementation for php.
    634         //Creates an md5 HMAC.
    635         //Eliminates the need to install mhash to compute a HMAC
    636         //by Lance Rushing
    637 
    638         $bytelen = 64; //byte length for md5
    639         if (strlen($key) > $bytelen) {
    640             $key = pack('H*', md5($key));
    641         }
    642         $key = str_pad($key, $bytelen, chr(0x00));
    643         $ipad = str_pad('', $bytelen, chr(0x36));
    644         $opad = str_pad('', $bytelen, chr(0x5c));
    645         $k_ipad = $key ^ $ipad;
    646         $k_opad = $key ^ $opad;
    647 
    648         return md5($k_opad . pack('H*', md5($k_ipad . $data)));
    649     }
    650 
    651     /**
    652      * Check connection state.
    653      *
    654      * @return bool True if connected
    655      */
    656     public function connected()
    657     {
    658         if (is_resource($this->smtp_conn)) {
    659             $sock_status = stream_get_meta_data($this->smtp_conn);
    660             if ($sock_status['eof']) {
    661                 //The socket is valid but we are not connected
    662                 $this->edebug(
    663                     'SMTP NOTICE: EOF caught while checking if connected',
    664                     self::DEBUG_CLIENT
    665                 );
    666                 $this->close();
    667 
    668                 return false;
    669             }
    670 
    671             return true; //everything looks good
    672         }
    673 
    674         return false;
    675     }
    676 
    677     /**
    678      * Close the socket and clean up the state of the class.
    679      * Don't use this function without first trying to use QUIT.
    680      *
    681      * @see quit()
    682      */
    683     public function close()
    684     {
    685         $this->setError('');
    686         $this->server_caps = null;
    687         $this->helo_rply = null;
    688         if (is_resource($this->smtp_conn)) {
    689             //Close the connection and cleanup
    690             fclose($this->smtp_conn);
    691             $this->smtp_conn = null; //Makes for cleaner serialization
    692             $this->edebug('Connection: closed', self::DEBUG_CONNECTION);
    693         }
    694     }
    695 
    696     /**
    697      * Send an SMTP DATA command.
    698      * Issues a data command and sends the msg_data to the server,
    699      * finializing the mail transaction. $msg_data is the message
    700      * that is to be send with the headers. Each header needs to be
    701      * on a single line followed by a <CRLF> with the message headers
    702      * and the message body being separated by an additional <CRLF>.
    703      * Implements RFC 821: DATA <CRLF>.
    704      *
    705      * @param string $msg_data Message data to send
    706      *
    707      * @return bool
    708      */
    709     public function data($msg_data)
    710     {
    711         //This will use the standard timelimit
    712         if (!$this->sendCommand('DATA', 'DATA', 354)) {
    713             return false;
    714         }
    715 
    716         /* The server is ready to accept data!
    717          * According to rfc821 we should not send more than 1000 characters on a single line (including the LE)
    718          * so we will break the data up into lines by \r and/or \n then if needed we will break each of those into
    719          * smaller lines to fit within the limit.
    720          * We will also look for lines that start with a '.' and prepend an additional '.'.
    721          * NOTE: this does not count towards line-length limit.
    722          */
    723 
    724         //Normalize line breaks before exploding
    725         $lines = explode("\n", str_replace(["\r\n", "\r"], "\n", $msg_data));
    726 
    727         /* To distinguish between a complete RFC822 message and a plain message body, we check if the first field
    728          * of the first line (':' separated) does not contain a space then it _should_ be a header and we will
    729          * process all lines before a blank line as headers.
    730          */
    731 
    732         $field = substr($lines[0], 0, strpos($lines[0], ':'));
    733         $in_headers = false;
    734         if (!empty($field) && strpos($field, ' ') === false) {
    735             $in_headers = true;
    736         }
    737 
    738         foreach ($lines as $line) {
    739             $lines_out = [];
    740             if ($in_headers && $line === '') {
    741                 $in_headers = false;
    742             }
    743             //Break this line up into several smaller lines if it's too long
    744             //Micro-optimisation: isset($str[$len]) is faster than (strlen($str) > $len),
    745             while (isset($line[self::MAX_LINE_LENGTH])) {
    746                 //Working backwards, try to find a space within the last MAX_LINE_LENGTH chars of the line to break on
    747                 //so as to avoid breaking in the middle of a word
    748                 $pos = strrpos(substr($line, 0, self::MAX_LINE_LENGTH), ' ');
    749                 //Deliberately matches both false and 0
    750                 if (!$pos) {
    751                     //No nice break found, add a hard break
    752                     $pos = self::MAX_LINE_LENGTH - 1;
    753                     $lines_out[] = substr($line, 0, $pos);
    754                     $line = substr($line, $pos);
    755                 } else {
    756                     //Break at the found point
    757                     $lines_out[] = substr($line, 0, $pos);
    758                     //Move along by the amount we dealt with
    759                     $line = substr($line, $pos + 1);
    760                 }
    761                 //If processing headers add a LWSP-char to the front of new line RFC822 section 3.1.1
    762                 if ($in_headers) {
    763                     $line = "\t" . $line;
    764                 }
    765             }
    766             $lines_out[] = $line;
    767 
    768             //Send the lines to the server
    769             foreach ($lines_out as $line_out) {
    770                 //Dot-stuffing as per RFC5321 section 4.5.2
    771                 //https://tools.ietf.org/html/rfc5321#section-4.5.2
    772                 if (!empty($line_out) && $line_out[0] === '.') {
    773                     $line_out = '.' . $line_out;
    774                 }
    775                 $this->client_send($line_out . static::LE, 'DATA');
    776             }
    777         }
    778 
    779         //Message data has been sent, complete the command
    780         //Increase timelimit for end of DATA command
    781         $savetimelimit = $this->Timelimit;
    782         $this->Timelimit *= 2;
    783         $result = $this->sendCommand('DATA END', '.', 250);
    784         $this->recordLastTransactionID();
    785         //Restore timelimit
    786         $this->Timelimit = $savetimelimit;
    787 
    788         return $result;
    789     }
    790 
    791     /**
    792      * Send an SMTP HELO or EHLO command.
    793      * Used to identify the sending server to the receiving server.
    794      * This makes sure that client and server are in a known state.
    795      * Implements RFC 821: HELO <SP> <domain> <CRLF>
    796      * and RFC 2821 EHLO.
    797      *
    798      * @param string $host The host name or IP to connect to
    799      *
    800      * @return bool
    801      */
    802     public function hello($host = '')
    803     {
    804         //Try extended hello first (RFC 2821)
    805         if ($this->sendHello('EHLO', $host)) {
    806             return true;
    807         }
    808 
    809         //Some servers shut down the SMTP service here (RFC 5321)
    810         if (substr($this->helo_rply, 0, 3) == '421') {
    811             return false;
    812         }
    813 
    814         return $this->sendHello('HELO', $host);
    815     }
    816 
    817     /**
    818      * Send an SMTP HELO or EHLO command.
    819      * Low-level implementation used by hello().
    820      *
    821      * @param string $hello The HELO string
    822      * @param string $host  The hostname to say we are
    823      *
    824      * @return bool
    825      *
    826      * @see hello()
    827      */
    828     protected function sendHello($hello, $host)
    829     {
    830         $noerror = $this->sendCommand($hello, $hello . ' ' . $host, 250);
    831         $this->helo_rply = $this->last_reply;
    832         if ($noerror) {
    833             $this->parseHelloFields($hello);
    834         } else {
    835             $this->server_caps = null;
    836         }
    837 
    838         return $noerror;
    839     }
    840 
    841     /**
    842      * Parse a reply to HELO/EHLO command to discover server extensions.
    843      * In case of HELO, the only parameter that can be discovered is a server name.
    844      *
    845      * @param string $type `HELO` or `EHLO`
    846      */
    847     protected function parseHelloFields($type)
    848     {
    849         $this->server_caps = [];
    850         $lines = explode("\n", $this->helo_rply);
    851 
    852         foreach ($lines as $n => $s) {
    853             //First 4 chars contain response code followed by - or space
    854             $s = trim(substr($s, 4));
    855             if (empty($s)) {
    856                 continue;
    857             }
    858             $fields = explode(' ', $s);
    859             if (!empty($fields)) {
    860                 if (!$n) {
    861                     $name = $type;
    862                     $fields = $fields[0];
    863                 } else {
    864                     $name = array_shift($fields);
    865                     switch ($name) {
    866                         case 'SIZE':
    867                             $fields = ($fields ? $fields[0] : 0);
    868                             break;
    869                         case 'AUTH':
    870                             if (!is_array($fields)) {
    871                                 $fields = [];
    872                             }
    873                             break;
    874                         default:
    875                             $fields = true;
    876                     }
    877                 }
    878                 $this->server_caps[$name] = $fields;
    879             }
    880         }
    881     }
    882 
    883     /**
    884      * Send an SMTP MAIL command.
    885      * Starts a mail transaction from the email address specified in
    886      * $from. Returns true if successful or false otherwise. If True
    887      * the mail transaction is started and then one or more recipient
    888      * commands may be called followed by a data command.
    889      * Implements RFC 821: MAIL <SP> FROM:<reverse-path> <CRLF>.
    890      *
    891      * @param string $from Source address of this message
    892      *
    893      * @return bool
    894      */
    895     public function mail($from)
    896     {
    897         $useVerp = ($this->do_verp ? ' XVERP' : '');
    898 
    899         return $this->sendCommand(
    900             'MAIL FROM',
    901             'MAIL FROM:<' . $from . '>' . $useVerp,
    902             250
    903         );
    904     }
    905 
    906     /**
    907      * Send an SMTP QUIT command.
    908      * Closes the socket if there is no error or the $close_on_error argument is true.
    909      * Implements from RFC 821: QUIT <CRLF>.
    910      *
    911      * @param bool $close_on_error Should the connection close if an error occurs?
    912      *
    913      * @return bool
    914      */
    915     public function quit($close_on_error = true)
    916     {
    917         $noerror = $this->sendCommand('QUIT', 'QUIT', 221);
    918         $err = $this->error; //Save any error
    919         if ($noerror || $close_on_error) {
    920             $this->close();
    921             $this->error = $err; //Restore any error from the quit command
    922         }
    923 
    924         return $noerror;
    925     }
    926 
    927     /**
    928      * Send an SMTP RCPT command.
    929      * Sets the TO argument to $toaddr.
    930      * Returns true if the recipient was accepted false if it was rejected.
    931      * Implements from RFC 821: RCPT <SP> TO:<forward-path> <CRLF>.
    932      *
    933      * @param string $address The address the message is being sent to
    934      * @param string $dsn     Comma separated list of DSN notifications. NEVER, SUCCESS, FAILURE
    935      *                        or DELAY. If you specify NEVER all other notifications are ignored.
    936      *
    937      * @return bool
    938      */
    939     public function recipient($address, $dsn = '')
    940     {
    941         if (empty($dsn)) {
    942             $rcpt = 'RCPT TO:<' . $address . '>';
    943         } else {
    944             $dsn = strtoupper($dsn);
    945             $notify = [];
    946 
    947             if (strpos($dsn, 'NEVER') !== false) {
    948                 $notify[] = 'NEVER';
    949             } else {
    950                 foreach (['SUCCESS', 'FAILURE', 'DELAY'] as $value) {
    951                     if (strpos($dsn, $value) !== false) {
    952                         $notify[] = $value;
    953                     }
    954                 }
    955             }
    956 
    957             $rcpt = 'RCPT TO:<' . $address . '> NOTIFY=' . implode(',', $notify);
    958         }
    959 
    960         return $this->sendCommand(
    961             'RCPT TO',
    962             $rcpt,
    963             [250, 251]
    964         );
    965     }
    966 
    967     /**
    968      * Send an SMTP RSET command.
    969      * Abort any transaction that is currently in progress.
    970      * Implements RFC 821: RSET <CRLF>.
    971      *
    972      * @return bool True on success
    973      */
    974     public function reset()
    975     {
    976         return $this->sendCommand('RSET', 'RSET', 250);
    977     }
    978 
    979     /**
    980      * Send a command to an SMTP server and check its return code.
    981      *
    982      * @param string    $command       The command name - not sent to the server
    983      * @param string    $commandstring The actual command to send
    984      * @param int|array $expect        One or more expected integer success codes
    985      *
    986      * @return bool True on success
    987      */
    988     protected function sendCommand($command, $commandstring, $expect)
    989     {
    990         if (!$this->connected()) {
    991             $this->setError("Called $command without being connected");
    992 
    993             return false;
    994         }
    995         //Reject line breaks in all commands
    996         if ((strpos($commandstring, "\n") !== false) || (strpos($commandstring, "\r") !== false)) {
    997             $this->setError("Command '$command' contained line breaks");
    998 
    999             return false;
   1000         }
   1001         $this->client_send($commandstring . static::LE, $command);
   1002 
   1003         $this->last_reply = $this->get_lines();
   1004         //Fetch SMTP code and possible error code explanation
   1005         $matches = [];
   1006         if (preg_match('/^([\d]{3})[ -](?:([\d]\\.[\d]\\.[\d]{1,2}) )?/', $this->last_reply, $matches)) {
   1007             $code = (int) $matches[1];
   1008             $code_ex = (count($matches) > 2 ? $matches[2] : null);
   1009             //Cut off error code from each response line
   1010             $detail = preg_replace(
   1011                 "/{$code}[ -]" .
   1012                 ($code_ex ? str_replace('.', '\\.', $code_ex) . ' ' : '') . '/m',
   1013                 '',
   1014                 $this->last_reply
   1015             );
   1016         } else {
   1017             //Fall back to simple parsing if regex fails
   1018             $code = (int) substr($this->last_reply, 0, 3);
   1019             $code_ex = null;
   1020             $detail = substr($this->last_reply, 4);
   1021         }
   1022 
   1023         $this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER);
   1024 
   1025         if (!in_array($code, (array) $expect, true)) {
   1026             $this->setError(
   1027                 "$command command failed",
   1028                 $detail,
   1029                 $code,
   1030                 $code_ex
   1031             );
   1032             $this->edebug(
   1033                 'SMTP ERROR: ' . $this->error['error'] . ': ' . $this->last_reply,
   1034                 self::DEBUG_CLIENT
   1035             );
   1036 
   1037             return false;
   1038         }
   1039 
   1040         $this->setError('');
   1041 
   1042         return true;
   1043     }
   1044 
   1045     /**
   1046      * Send an SMTP SAML command.
   1047      * Starts a mail transaction from the email address specified in $from.
   1048      * Returns true if successful or false otherwise. If True
   1049      * the mail transaction is started and then one or more recipient
   1050      * commands may be called followed by a data command. This command
   1051      * will send the message to the users terminal if they are logged
   1052      * in and send them an email.
   1053      * Implements RFC 821: SAML <SP> FROM:<reverse-path> <CRLF>.
   1054      *
   1055      * @param string $from The address the message is from
   1056      *
   1057      * @return bool
   1058      */
   1059     public function sendAndMail($from)
   1060     {
   1061         return $this->sendCommand('SAML', "SAML FROM:$from", 250);
   1062     }
   1063 
   1064     /**
   1065      * Send an SMTP VRFY command.
   1066      *
   1067      * @param string $name The name to verify
   1068      *
   1069      * @return bool
   1070      */
   1071     public function verify($name)
   1072     {
   1073         return $this->sendCommand('VRFY', "VRFY $name", [250, 251]);
   1074     }
   1075 
   1076     /**
   1077      * Send an SMTP NOOP command.
   1078      * Used to keep keep-alives alive, doesn't actually do anything.
   1079      *
   1080      * @return bool
   1081      */
   1082     public function noop()
   1083     {
   1084         return $this->sendCommand('NOOP', 'NOOP', 250);
   1085     }
   1086 
   1087     /**
   1088      * Send an SMTP TURN command.
   1089      * This is an optional command for SMTP that this class does not support.
   1090      * This method is here to make the RFC821 Definition complete for this class
   1091      * and _may_ be implemented in future.
   1092      * Implements from RFC 821: TURN <CRLF>.
   1093      *
   1094      * @return bool
   1095      */
   1096     public function turn()
   1097     {
   1098         $this->setError('The SMTP TURN command is not implemented');
   1099         $this->edebug('SMTP NOTICE: ' . $this->error['error'], self::DEBUG_CLIENT);
   1100 
   1101         return false;
   1102     }
   1103 
   1104     /**
   1105      * Send raw data to the server.
   1106      *
   1107      * @param string $data    The data to send
   1108      * @param string $command Optionally, the command this is part of, used only for controlling debug output
   1109      *
   1110      * @return int|bool The number of bytes sent to the server or false on error
   1111      */
   1112     public function client_send($data, $command = '')
   1113     {
   1114         //If SMTP transcripts are left enabled, or debug output is posted online
   1115         //it can leak credentials, so hide credentials in all but lowest level
   1116         if (
   1117             self::DEBUG_LOWLEVEL > $this->do_debug &&
   1118             in_array($command, ['User & Password', 'Username', 'Password'], true)
   1119         ) {
   1120             $this->edebug('CLIENT -> SERVER: [credentials hidden]', self::DEBUG_CLIENT);
   1121         } else {
   1122             $this->edebug('CLIENT -> SERVER: ' . $data, self::DEBUG_CLIENT);
   1123         }
   1124         set_error_handler([$this, 'errorHandler']);
   1125         $result = fwrite($this->smtp_conn, $data);
   1126         restore_error_handler();
   1127 
   1128         return $result;
   1129     }
   1130 
   1131     /**
   1132      * Get the latest error.
   1133      *
   1134      * @return array
   1135      */
   1136     public function getError()
   1137     {
   1138         return $this->error;
   1139     }
   1140 
   1141     /**
   1142      * Get SMTP extensions available on the server.
   1143      *
   1144      * @return array|null
   1145      */
   1146     public function getServerExtList()
   1147     {
   1148         return $this->server_caps;
   1149     }
   1150 
   1151     /**
   1152      * Get metadata about the SMTP server from its HELO/EHLO response.
   1153      * The method works in three ways, dependent on argument value and current state:
   1154      *   1. HELO/EHLO has not been sent - returns null and populates $this->error.
   1155      *   2. HELO has been sent -
   1156      *     $name == 'HELO': returns server name
   1157      *     $name == 'EHLO': returns boolean false
   1158      *     $name == any other string: returns null and populates $this->error
   1159      *   3. EHLO has been sent -
   1160      *     $name == 'HELO'|'EHLO': returns the server name
   1161      *     $name == any other string: if extension $name exists, returns True
   1162      *       or its options (e.g. AUTH mechanisms supported). Otherwise returns False.
   1163      *
   1164      * @param string $name Name of SMTP extension or 'HELO'|'EHLO'
   1165      *
   1166      * @return string|bool|null
   1167      */
   1168     public function getServerExt($name)
   1169     {
   1170         if (!$this->server_caps) {
   1171             $this->setError('No HELO/EHLO was sent');
   1172 
   1173             return;
   1174         }
   1175 
   1176         if (!array_key_exists($name, $this->server_caps)) {
   1177             if ('HELO' === $name) {
   1178                 return $this->server_caps['EHLO'];
   1179             }
   1180             if ('EHLO' === $name || array_key_exists('EHLO', $this->server_caps)) {
   1181                 return false;
   1182             }
   1183             $this->setError('HELO handshake was used; No information about server extensions available');
   1184 
   1185             return;
   1186         }
   1187 
   1188         return $this->server_caps[$name];
   1189     }
   1190 
   1191     /**
   1192      * Get the last reply from the server.
   1193      *
   1194      * @return string
   1195      */
   1196     public function getLastReply()
   1197     {
   1198         return $this->last_reply;
   1199     }
   1200 
   1201     /**
   1202      * Read the SMTP server's response.
   1203      * Either before eof or socket timeout occurs on the operation.
   1204      * With SMTP we can tell if we have more lines to read if the
   1205      * 4th character is '-' symbol. If it is a space then we don't
   1206      * need to read anything else.
   1207      *
   1208      * @return string
   1209      */
   1210     protected function get_lines()
   1211     {
   1212         //If the connection is bad, give up straight away
   1213         if (!is_resource($this->smtp_conn)) {
   1214             return '';
   1215         }
   1216         $data = '';
   1217         $endtime = 0;
   1218         stream_set_timeout($this->smtp_conn, $this->Timeout);
   1219         if ($this->Timelimit > 0) {
   1220             $endtime = time() + $this->Timelimit;
   1221         }
   1222         $selR = [$this->smtp_conn];
   1223         $selW = null;
   1224         while (is_resource($this->smtp_conn) && !feof($this->smtp_conn)) {
   1225             //Must pass vars in here as params are by reference
   1226             //solution for signals inspired by https://github.com/symfony/symfony/pull/6540
   1227             set_error_handler([$this, 'errorHandler']);
   1228             $n = stream_select($selR, $selW, $selW, $this->Timelimit);
   1229             restore_error_handler();
   1230 
   1231             if ($n === false) {
   1232                 $message = $this->getError()['detail'];
   1233 
   1234                 $this->edebug(
   1235                     'SMTP -> get_lines(): select failed (' . $message . ')',
   1236                     self::DEBUG_LOWLEVEL
   1237                 );
   1238 
   1239                 //stream_select returns false when the `select` system call is interrupted
   1240                 //by an incoming signal, try the select again
   1241                 if (stripos($message, 'interrupted system call') !== false) {
   1242                     $this->edebug(
   1243                         'SMTP -> get_lines(): retrying stream_select',
   1244                         self::DEBUG_LOWLEVEL
   1245                     );
   1246                     $this->setError('');
   1247                     continue;
   1248                 }
   1249 
   1250                 break;
   1251             }
   1252 
   1253             if (!$n) {
   1254                 $this->edebug(
   1255                     'SMTP -> get_lines(): select timed-out in (' . $this->Timelimit . ' sec)',
   1256                     self::DEBUG_LOWLEVEL
   1257                 );
   1258                 break;
   1259             }
   1260 
   1261             //Deliberate noise suppression - errors are handled afterwards
   1262             $str = @fgets($this->smtp_conn, self::MAX_REPLY_LENGTH);
   1263             $this->edebug('SMTP INBOUND: "' . trim($str) . '"', self::DEBUG_LOWLEVEL);
   1264             $data .= $str;
   1265             //If response is only 3 chars (not valid, but RFC5321 S4.2 says it must be handled),
   1266             //or 4th character is a space or a line break char, we are done reading, break the loop.
   1267             //String array access is a significant micro-optimisation over strlen
   1268             if (!isset($str[3]) || $str[3] === ' ' || $str[3] === "\r" || $str[3] === "\n") {
   1269                 break;
   1270             }
   1271             //Timed-out? Log and break
   1272             $info = stream_get_meta_data($this->smtp_conn);
   1273             if ($info['timed_out']) {
   1274                 $this->edebug(
   1275                     'SMTP -> get_lines(): stream timed-out (' . $this->Timeout . ' sec)',
   1276                     self::DEBUG_LOWLEVEL
   1277                 );
   1278                 break;
   1279             }
   1280             //Now check if reads took too long
   1281             if ($endtime && time() > $endtime) {
   1282                 $this->edebug(
   1283                     'SMTP -> get_lines(): timelimit reached (' .
   1284                     $this->Timelimit . ' sec)',
   1285                     self::DEBUG_LOWLEVEL
   1286                 );
   1287                 break;
   1288             }
   1289         }
   1290 
   1291         return $data;
   1292     }
   1293 
   1294     /**
   1295      * Enable or disable VERP address generation.
   1296      *
   1297      * @param bool $enabled
   1298      */
   1299     public function setVerp($enabled = false)
   1300     {
   1301         $this->do_verp = $enabled;
   1302     }
   1303 
   1304     /**
   1305      * Get VERP address generation mode.
   1306      *
   1307      * @return bool
   1308      */
   1309     public function getVerp()
   1310     {
   1311         return $this->do_verp;
   1312     }
   1313 
   1314     /**
   1315      * Set error messages and codes.
   1316      *
   1317      * @param string $message      The error message
   1318      * @param string $detail       Further detail on the error
   1319      * @param string $smtp_code    An associated SMTP error code
   1320      * @param string $smtp_code_ex Extended SMTP code
   1321      */
   1322     protected function setError($message, $detail = '', $smtp_code = '', $smtp_code_ex = '')
   1323     {
   1324         $this->error = [
   1325             'error' => $message,
   1326             'detail' => $detail,
   1327             'smtp_code' => $smtp_code,
   1328             'smtp_code_ex' => $smtp_code_ex,
   1329         ];
   1330     }
   1331 
   1332     /**
   1333      * Set debug output method.
   1334      *
   1335      * @param string|callable $method The name of the mechanism to use for debugging output, or a callable to handle it
   1336      */
   1337     public function setDebugOutput($method = 'echo')
   1338     {
   1339         $this->Debugoutput = $method;
   1340     }
   1341 
   1342     /**
   1343      * Get debug output method.
   1344      *
   1345      * @return string
   1346      */
   1347     public function getDebugOutput()
   1348     {
   1349         return $this->Debugoutput;
   1350     }
   1351 
   1352     /**
   1353      * Set debug output level.
   1354      *
   1355      * @param int $level
   1356      */
   1357     public function setDebugLevel($level = 0)
   1358     {
   1359         $this->do_debug = $level;
   1360     }
   1361 
   1362     /**
   1363      * Get debug output level.
   1364      *
   1365      * @return int
   1366      */
   1367     public function getDebugLevel()
   1368     {
   1369         return $this->do_debug;
   1370     }
   1371 
   1372     /**
   1373      * Set SMTP timeout.
   1374      *
   1375      * @param int $timeout The timeout duration in seconds
   1376      */
   1377     public function setTimeout($timeout = 0)
   1378     {
   1379         $this->Timeout = $timeout;
   1380     }
   1381 
   1382     /**
   1383      * Get SMTP timeout.
   1384      *
   1385      * @return int
   1386      */
   1387     public function getTimeout()
   1388     {
   1389         return $this->Timeout;
   1390     }
   1391 
   1392     /**
   1393      * Reports an error number and string.
   1394      *
   1395      * @param int    $errno   The error number returned by PHP
   1396      * @param string $errmsg  The error message returned by PHP
   1397      * @param string $errfile The file the error occurred in
   1398      * @param int    $errline The line number the error occurred on
   1399      */
   1400     protected function errorHandler($errno, $errmsg, $errfile = '', $errline = 0)
   1401     {
   1402         $notice = 'Connection failed.';
   1403         $this->setError(
   1404             $notice,
   1405             $errmsg,
   1406             (string) $errno
   1407         );
   1408         $this->edebug(
   1409             "$notice Error #$errno: $errmsg [$errfile line $errline]",
   1410             self::DEBUG_CONNECTION
   1411         );
   1412     }
   1413 
   1414     /**
   1415      * Extract and return the ID of the last SMTP transaction based on
   1416      * a list of patterns provided in SMTP::$smtp_transaction_id_patterns.
   1417      * Relies on the host providing the ID in response to a DATA command.
   1418      * If no reply has been received yet, it will return null.
   1419      * If no pattern was matched, it will return false.
   1420      *
   1421      * @return bool|string|null
   1422      */
   1423     protected function recordLastTransactionID()
   1424     {
   1425         $reply = $this->getLastReply();
   1426 
   1427         if (empty($reply)) {
   1428             $this->last_smtp_transaction_id = null;
   1429         } else {
   1430             $this->last_smtp_transaction_id = false;
   1431             foreach ($this->smtp_transaction_id_patterns as $smtp_transaction_id_pattern) {
   1432                 $matches = [];
   1433                 if (preg_match($smtp_transaction_id_pattern, $reply, $matches)) {
   1434                     $this->last_smtp_transaction_id = trim($matches[1]);
   1435                     break;
   1436                 }
   1437             }
   1438         }
   1439 
   1440         return $this->last_smtp_transaction_id;
   1441     }
   1442 
   1443     /**
   1444      * Get the queue/transaction ID of the last SMTP transaction
   1445      * If no reply has been received yet, it will return null.
   1446      * If no pattern was matched, it will return false.
   1447      *
   1448      * @return bool|string|null
   1449      *
   1450      * @see recordLastTransactionID()
   1451      */
   1452     public function getLastTransactionID()
   1453     {
   1454         return $this->last_smtp_transaction_id;
   1455     }
   1456 }