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PHP Decode

<?php /** * PHPMailer RFC821 SMTP email transport class. * PHP Version 5.5. * *..

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<?php 
 
/** 
 * PHPMailer RFC821 SMTP email transport class. 
 * PHP Version 5.5. 
 * 
 * @see       https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project 
 * 
 * @author    Marcus Bointon (Synchro/coolbru) <[email protected]> 
 * @author    Jim Jagielski (jimjag) <[email protected]> 
 * @author    Andy Prevost (codeworxtech) <[email protected]> 
 * @author    Brent R. Matzelle (original founder) 
 * @copyright 2012 - 2020 Marcus Bointon 
 * @copyright 2010 - 2012 Jim Jagielski 
 * @copyright 2004 - 2009 Andy Prevost 
 * @license   http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License 
 * @note      This program is distributed in the hope that it will be useful - WITHOUT 
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 
 * FITNESS FOR A PARTICULAR PURPOSE. 
 */ 
 
namespace PHPMailer\PHPMailer; 
 
/** 
 * PHPMailer RFC821 SMTP email transport class. 
 * Implements RFC 821 SMTP commands and provides some utility methods for sending mail to an SMTP server. 
 * 
 * @author Chris Ryan 
 * @author Marcus Bointon <[email protected]> 
 */ 
class SMTP 
{ 
    /** 
     * The PHPMailer SMTP version number. 
     * 
     * @var string 
     */ 
    const VERSION = '6.5.1'; 
 
    /** 
     * SMTP line break constant. 
     * 
     * @var string 
     */ 
    const LE = "
"; 
 
    /** 
     * The SMTP port to use if one is not specified. 
     * 
     * @var int 
     */ 
    const DEFAULT_PORT = 25; 
 
    /** 
     * The maximum line length allowed by RFC 5321 section 4.5.3.1.6, 
     * *excluding* a trailing CRLF break. 
     * 
     * @see https://tools.ietf.org/html/rfc5321#section-4.5.3.1.6 
     * 
     * @var int 
     */ 
    const MAX_LINE_LENGTH = 998; 
 
    /** 
     * The maximum line length allowed for replies in RFC 5321 section 4.5.3.1.5, 
     * *including* a trailing CRLF line break. 
     * 
     * @see https://tools.ietf.org/html/rfc5321#section-4.5.3.1.5 
     * 
     * @var int 
     */ 
    const MAX_REPLY_LENGTH = 512; 
 
    /** 
     * Debug level for no output. 
     * 
     * @var int 
     */ 
    const DEBUG_OFF = 0; 
 
    /** 
     * Debug level to show client -> server messages. 
     * 
     * @var int 
     */ 
    const DEBUG_CLIENT = 1; 
 
    /** 
     * Debug level to show client -> server and server -> client messages. 
     * 
     * @var int 
     */ 
    const DEBUG_SERVER = 2; 
 
    /** 
     * Debug level to show connection status, client -> server and server -> client messages. 
     * 
     * @var int 
     */ 
    const DEBUG_CONNECTION = 3; 
 
    /** 
     * Debug level to show all messages. 
     * 
     * @var int 
     */ 
    const DEBUG_LOWLEVEL = 4; 
 
    /** 
     * Debug output level. 
     * Options: 
     * * self::DEBUG_OFF (`0`) No debug output, default 
     * * self::DEBUG_CLIENT (`1`) Client commands 
     * * self::DEBUG_SERVER (`2`) Client commands and server responses 
     * * self::DEBUG_CONNECTION (`3`) As DEBUG_SERVER plus connection status 
     * * self::DEBUG_LOWLEVEL (`4`) Low-level data output, all messages. 
     * 
     * @var int 
     */ 
    public $do_debug = self::DEBUG_OFF; 
 
    /** 
     * How to handle debug output. 
     * Options: 
     * * `echo` Output plain-text as-is, appropriate for CLI 
     * * `html` Output escaped, line breaks converted to `<br>`, appropriate for browser output 
     * * `error_log` Output to error log as configured in php.ini 
     * Alternatively, you can provide a callable expecting two params: a message string and the debug level: 
     * 
     * ```php 
     * $smtp->Debugoutput = function($str, $level) {echo "debug level $level; message: $str";}; 
     * ``` 
     * 
     * Alternatively, you can pass in an instance of a PSR-3 compatible logger, though only `debug` 
     * level output is used: 
     * 
     * ```php 
     * $mail->Debugoutput = new myPsr3Logger; 
     * ``` 
     * 
     * @var string|callable|\Psr\Log\LoggerInterface 
     */ 
    public $Debugoutput = 'echo'; 
 
    /** 
     * Whether to use VERP. 
     * 
     * @see http://en.wikipedia.org/wiki/Variable_envelope_return_path 
     * @see http://www.postfix.org/VERP_README.html Info on VERP 
     * 
     * @var bool 
     */ 
    public $do_verp = false; 
 
    /** 
     * The timeout value for connection, in seconds. 
     * Default of 5 minutes (300sec) is from RFC2821 section 4.5.3.2. 
     * This needs to be quite high to function correctly with hosts using greetdelay as an anti-spam measure. 
     * 
     * @see http://tools.ietf.org/html/rfc2821#section-4.5.3.2 
     * 
     * @var int 
     */ 
    public $Timeout = 300; 
 
    /** 
     * How long to wait for commands to complete, in seconds. 
     * Default of 5 minutes (300sec) is from RFC2821 section 4.5.3.2. 
     * 
     * @var int 
     */ 
    public $Timelimit = 300; 
 
    /** 
     * Patterns to extract an SMTP transaction id from reply to a DATA command. 
     * The first capture group in each regex will be used as the ID. 
     * MS ESMTP returns the message ID, which may not be correct for internal tracking. 
     * 
     * @var string[] 
     */ 
    protected $smtp_transaction_id_patterns = [ 
        'exim' => '/[\d]{3} OK id=(.*)/', 
        'sendmail' => '/[\d]{3} 2.0.0 (.*) Message/', 
        'postfix' => '/[\d]{3} 2.0.0 Ok: queued as (.*)/', 
        'Microsoft_ESMTP' => '/[0-9]{3} 2.[\d].0 (.*)@(?:.*) Queued mail for delivery/', 
        'Amazon_SES' => '/[\d]{3} Ok (.*)/', 
        'SendGrid' => '/[\d]{3} Ok: queued as (.*)/', 
        'CampaignMonitor' => '/[\d]{3} 2.0.0 OK:([a-zA-Z\d]{48})/', 
        'Haraka' => '/[\d]{3} Message Queued \((.*)\)/', 
    ]; 
 
    /** 
     * The last transaction ID issued in response to a DATA command, 
     * if one was detected. 
     * 
     * @var string|bool|null 
     */ 
    protected $last_smtp_transaction_id; 
 
    /** 
     * The socket for the server connection. 
     * 
     * @var ?resource 
     */ 
    protected $smtp_conn; 
 
    /** 
     * Error information, if any, for the last SMTP command. 
     * 
     * @var array 
     */ 
    protected $error = [ 
        'error' => '', 
        'detail' => '', 
        'smtp_code' => '', 
        'smtp_code_ex' => '', 
    ]; 
 
    /** 
     * The reply the server sent to us for HELO. 
     * If null, no HELO string has yet been received. 
     * 
     * @var string|null 
     */ 
    protected $helo_rply; 
 
    /** 
     * The set of SMTP extensions sent in reply to EHLO command. 
     * Indexes of the array are extension names. 
     * Value at index 'HELO' or 'EHLO' (according to command that was sent) 
     * represents the server name. In case of HELO it is the only element of the array. 
     * Other values can be boolean TRUE or an array containing extension options. 
     * If null, no HELO/EHLO string has yet been received. 
     * 
     * @var array|null 
     */ 
    protected $server_caps; 
 
    /** 
     * The most recent reply received from the server. 
     * 
     * @var string 
     */ 
    protected $last_reply = ''; 
 
    /** 
     * Output debugging info via a user-selected method. 
     * 
     * @param string $str   Debug string to output 
     * @param int    $level The debug level of this message; see DEBUG_* constants 
     * 
     * @see SMTP::$Debugoutput 
     * @see SMTP::$do_debug 
     */ 
    protected function edebug($str, $level = 0) 
    { 
        if ($level > $this->do_debug) { 
            return; 
        } 
        //Is this a PSR-3 logger? 
        if ($this->Debugoutput instanceof \Psr\Log\LoggerInterface) { 
            $this->Debugoutput->debug($str); 
 
            return; 
        } 
        //Avoid clash with built-in function names 
        if (is_callable($this->Debugoutput) && !in_array($this->Debugoutput, ['error_log', 'html', 'echo'])) { 
            call_user_func($this->Debugoutput, $str, $level); 
 
            return; 
        } 
        switch ($this->Debugoutput) { 
            case 'error_log': 
                //Don't output, just log 
                error_log($str); 
                break; 
            case 'html': 
                //Cleans up output a bit for a better looking, HTML-safe output 
                echo gmdate('Y-m-d H:i:s'), ' ', htmlentities( 
                    preg_replace('/[
]+/', '', $str), 
                    ENT_QUOTES, 
                    'UTF-8' 
                ), "<br>
"; 
                break; 
            case 'echo': 
            default: 
                //Normalize line breaks 
                $str = preg_replace('/
|
/m', "
", $str); 
                echo gmdate('Y-m-d H:i:s'), 
                "	", 
                    //Trim trailing space 
                trim( 
                    //Indent for readability, except for trailing break 
                    str_replace( 
                        "
", 
                        "
                   	                  ", 
                        trim($str) 
                    ) 
                ), 
                "
"; 
        } 
    } 
 
    /** 
     * Connect to an SMTP server. 
     * 
     * @param string $host    SMTP server IP or host name 
     * @param int    $port    The port number to connect to 
     * @param int    $timeout How long to wait for the connection to open 
     * @param array  $options An array of options for stream_context_create() 
     * 
     * @return bool 
     */ 
    public function connect($host, $port = null, $timeout = 30, $options = []) 
    { 
        //Clear errors to avoid confusion 
        $this->setError(''); 
        //Make sure we are __not__ connected 
        if ($this->connected()) { 
            //Already connected, generate error 
            $this->setError('Already connected to a server'); 
 
            return false; 
        } 
        if (empty($port)) { 
            $port = self::DEFAULT_PORT; 
        } 
        //Connect to the SMTP server 
        $this->edebug( 
            "Connection: opening to $host:$port, timeout=$timeout, options=" . 
            (count($options) > 0 ? var_export($options, true) : 'array()'), 
            self::DEBUG_CONNECTION 
        ); 
 
        $this->smtp_conn = $this->getSMTPConnection($host, $port, $timeout, $options); 
 
        if ($this->smtp_conn === false) { 
            //Error info already set inside `getSMTPConnection()` 
            return false; 
        } 
 
        $this->edebug('Connection: opened', self::DEBUG_CONNECTION); 
 
        //Get any announcement 
        $this->last_reply = $this->get_lines(); 
        $this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER); 
        $responseCode = (int)substr($this->last_reply, 0, 3); 
        if ($responseCode === 220) { 
            return true; 
        } 
        //Anything other than a 220 response means something went wrong 
        //RFC 5321 says the server will wait for us to send a QUIT in response to a 554 error 
        //https://tools.ietf.org/html/rfc5321#section-3.1 
        if ($responseCode === 554) { 
            $this->quit(); 
        } 
        //This will handle 421 responses which may not wait for a QUIT (e.g. if the server is being shut down) 
        $this->edebug('Connection: closing due to error', self::DEBUG_CONNECTION); 
        $this->close(); 
        return false; 
    } 
 
    /** 
     * Create connection to the SMTP server. 
     * 
     * @param string $host    SMTP server IP or host name 
     * @param int    $port    The port number to connect to 
     * @param int    $timeout How long to wait for the connection to open 
     * @param array  $options An array of options for stream_context_create() 
     * 
     * @return false|resource 
     */ 
    protected function getSMTPConnection($host, $port = null, $timeout = 30, $options = []) 
    { 
        static $streamok; 
        //This is enabled by default since 5.0.0 but some providers disable it 
        //Check this once and cache the result 
        if (null === $streamok) { 
            $streamok = function_exists('stream_socket_client'); 
        } 
 
        $errno = 0; 
        $errstr = ''; 
        if ($streamok) { 
            $socket_context = stream_context_create($options); 
            set_error_handler([$this, 'errorHandler']); 
            $connection = stream_socket_client( 
                $host . ':' . $port, 
                $errno, 
                $errstr, 
                $timeout, 
                STREAM_CLIENT_CONNECT, 
                $socket_context 
            ); 
            restore_error_handler(); 
        } else { 
            //Fall back to fsockopen which should work in more places, but is missing some features 
            $this->edebug( 
                'Connection: stream_socket_client not available, falling back to fsockopen', 
                self::DEBUG_CONNECTION 
            ); 
            set_error_handler([$this, 'errorHandler']); 
            $connection = fsockopen( 
                $host, 
                $port, 
                $errno, 
                $errstr, 
                $timeout 
            ); 
            restore_error_handler(); 
        } 
 
        //Verify we connected properly 
        if (!is_resource($connection)) { 
            $this->setError( 
                'Failed to connect to server', 
                '', 
                (string) $errno, 
                $errstr 
            ); 
            $this->edebug( 
                'SMTP ERROR: ' . $this->error['error'] 
                . ": $errstr ($errno)", 
                self::DEBUG_CLIENT 
            ); 
 
            return false; 
        } 
 
        //SMTP server can take longer to respond, give longer timeout for first read 
        //Windows does not have support for this timeout function 
        if (strpos(PHP_OS, 'WIN') !== 0) { 
            $max = (int)ini_get('max_execution_time'); 
            //Don't bother if unlimited, or if set_time_limit is disabled 
            if (0 !== $max && $timeout > $max && strpos(ini_get('disable_functions'), 'set_time_limit') === false) { 
                @set_time_limit($timeout); 
            } 
            stream_set_timeout($connection, $timeout, 0); 
        } 
 
        return $connection; 
    } 
 
    /** 
     * Initiate a TLS (encrypted) session. 
     * 
     * @return bool 
     */ 
    public function startTLS() 
    { 
        if (!$this->sendCommand('STARTTLS', 'STARTTLS', 220)) { 
            return false; 
        } 
 
        //Allow the best TLS version(s) we can 
        $crypto_method = STREAM_CRYPTO_METHOD_TLS_CLIENT; 
 
        //PHP 5.6.7 dropped inclusion of TLS 1.1 and 1.2 in STREAM_CRYPTO_METHOD_TLS_CLIENT 
        //so add them back in manually if we can 
        if (defined('STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT')) { 
            $crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT; 
            $crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT; 
        } 
 
        //Begin encrypted connection 
        set_error_handler([$this, 'errorHandler']); 
        $crypto_ok = stream_socket_enable_crypto( 
            $this->smtp_conn, 
            true, 
            $crypto_method 
        ); 
        restore_error_handler(); 
 
        return (bool) $crypto_ok; 
    } 
 
    /** 
     * Perform SMTP authentication. 
     * Must be run after hello(). 
     * 
     * @see    hello() 
     * 
     * @param string $username The user name 
     * @param string $password The password 
     * @param string $authtype The auth type (CRAM-MD5, PLAIN, LOGIN, XOAUTH2) 
     * @param OAuth  $OAuth    An optional OAuth instance for XOAUTH2 authentication 
     * 
     * @return bool True if successfully authenticated 
     */ 
    public function authenticate( 
        $username, 
        $password, 
        $authtype = null, 
        $OAuth = null 
    ) { 
        if (!$this->server_caps) { 
            $this->setError('Authentication is not allowed before HELO/EHLO'); 
 
            return false; 
        } 
 
        if (array_key_exists('EHLO', $this->server_caps)) { 
            //SMTP extensions are available; try to find a proper authentication method 
            if (!array_key_exists('AUTH', $this->server_caps)) { 
                $this->setError('Authentication is not allowed at this stage'); 
                //'at this stage' means that auth may be allowed after the stage changes 
                //e.g. after STARTTLS 
 
                return false; 
            } 
 
            $this->edebug('Auth method requested: ' . ($authtype ?: 'UNSPECIFIED'), self::DEBUG_LOWLEVEL); 
            $this->edebug( 
                'Auth methods available on the server: ' . implode(',', $this->server_caps['AUTH']), 
                self::DEBUG_LOWLEVEL 
            ); 
 
            //If we have requested a specific auth type, check the server supports it before trying others 
            if (null !== $authtype && !in_array($authtype, $this->server_caps['AUTH'], true)) { 
                $this->edebug('Requested auth method not available: ' . $authtype, self::DEBUG_LOWLEVEL); 
                $authtype = null; 
            } 
 
            if (empty($authtype)) { 
                //If no auth mechanism is specified, attempt to use these, in this order 
                //Try CRAM-MD5 first as it's more secure than the others 
                foreach (['CRAM-MD5', 'LOGIN', 'PLAIN', 'XOAUTH2'] as $method) { 
                    if (in_array($method, $this->server_caps['AUTH'], true)) { 
                        $authtype = $method; 
                        break; 
                    } 
                } 
                if (empty($authtype)) { 
                    $this->setError('No supported authentication methods found'); 
 
                    return false; 
                } 
                $this->edebug('Auth method selected: ' . $authtype, self::DEBUG_LOWLEVEL); 
            } 
 
            if (!in_array($authtype, $this->server_caps['AUTH'], true)) { 
                $this->setError("The requested authentication method \"$authtype\" is not supported by the server"); 
 
                return false; 
            } 
        } elseif (empty($authtype)) { 
            $authtype = 'LOGIN'; 
        } 
        switch ($authtype) { 
            case 'PLAIN': 
                //Start authentication 
                if (!$this->sendCommand('AUTH', 'AUTH PLAIN', 334)) { 
                    return false; 
                } 
                //Send encoded username and password 
                if ( 
                    //Format from https://tools.ietf.org/html/rfc4616#section-2 
                    //We skip the first field (it's forgery), so the string starts with a null byte 
                    !$this->sendCommand( 
                        'User & Password', 
                        base64_encode("" . $username . "" . $password), 
                        235 
                    ) 
                ) { 
                    return false; 
                } 
                break; 
            case 'LOGIN': 
                //Start authentication 
                if (!$this->sendCommand('AUTH', 'AUTH LOGIN', 334)) { 
                    return false; 
                } 
                if (!$this->sendCommand('Username', base64_encode($username), 334)) { 
                    return false; 
                } 
                if (!$this->sendCommand('Password', base64_encode($password), 235)) { 
                    return false; 
                } 
                break; 
            case 'CRAM-MD5': 
                //Start authentication 
                if (!$this->sendCommand('AUTH CRAM-MD5', 'AUTH CRAM-MD5', 334)) { 
                    return false; 
                } 
                //Get the challenge 
                $challenge = base64_decode(substr($this->last_reply, 4)); 
 
                //Build the response 
                $response = $username . ' ' . $this->hmac($challenge, $password); 
 
                //send encoded credentials 
                return $this->sendCommand('Username', base64_encode($response), 235); 
            case 'XOAUTH2': 
                //The OAuth instance must be set up prior to requesting auth. 
                if (null === $OAuth) { 
                    return false; 
                } 
                $oauth = $OAuth->getOauth64(); 
 
                //Start authentication 
                if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2 ' . $oauth, 235)) { 
                    return false; 
                } 
                break; 
            default: 
                $this->setError("Authentication method \"$authtype\" is not supported"); 
 
                return false; 
        } 
 
        return true; 
    } 
 
    /** 
     * Calculate an MD5 HMAC hash. 
     * Works like hash_hmac('md5', $data, $key) 
     * in case that function is not available. 
     * 
     * @param string $data The data to hash 
     * @param string $key  The key to hash with 
     * 
     * @return string 
     */ 
    protected function hmac($data, $key) 
    { 
        if (function_exists('hash_hmac')) { 
            return hash_hmac('md5', $data, $key); 
        } 
 
        //The following borrowed from 
        //http://php.net/manual/en/function.mhash.php#27225 
 
        //RFC 2104 HMAC implementation for php. 
        //Creates an md5 HMAC. 
        //Eliminates the need to install mhash to compute a HMAC 
        //by Lance Rushing 
 
        $bytelen = 64; //byte length for md5 
        if (strlen($key) > $bytelen) { 
            $key = pack('H*', md5($key)); 
        } 
        $key = str_pad($key, $bytelen, chr(0x00)); 
        $ipad = str_pad('', $bytelen, chr(0x36)); 
        $opad = str_pad('', $bytelen, chr(0x5c)); 
        $k_ipad = $key ^ $ipad; 
        $k_opad = $key ^ $opad; 
 
        return md5($k_opad . pack('H*', md5($k_ipad . $data))); 
    } 
 
    /** 
     * Check connection state. 
     * 
     * @return bool True if connected 
     */ 
    public function connected() 
    { 
        if (is_resource($this->smtp_conn)) { 
            $sock_status = stream_get_meta_data($this->smtp_conn); 
            if ($sock_status['eof']) { 
                //The socket is valid but we are not connected 
                $this->edebug( 
                    'SMTP NOTICE: EOF caught while checking if connected', 
                    self::DEBUG_CLIENT 
                ); 
                $this->close(); 
 
                return false; 
            } 
 
            return true; //everything looks good 
        } 
 
        return false; 
    } 
 
    /** 
     * Close the socket and clean up the state of the class. 
     * Don't use this function without first trying to use QUIT. 
     * 
     * @see quit() 
     */ 
    public function close() 
    { 
        $this->setError(''); 
        $this->server_caps = null; 
        $this->helo_rply = null; 
        if (is_resource($this->smtp_conn)) { 
            //Close the connection and cleanup 
            fclose($this->smtp_conn); 
            $this->smtp_conn = null; //Makes for cleaner serialization 
            $this->edebug('Connection: closed', self::DEBUG_CONNECTION); 
        } 
    } 
 
    /** 
     * Send an SMTP DATA command. 
     * Issues a data command and sends the msg_data to the server, 
     * finializing the mail transaction. $msg_data is the message 
     * that is to be send with the headers. Each header needs to be 
     * on a single line followed by a <CRLF> with the message headers 
     * and the message body being separated by an additional <CRLF>. 
     * Implements RFC 821: DATA <CRLF>. 
     * 
     * @param string $msg_data Message data to send 
     * 
     * @return bool 
     */ 
    public function data($msg_data) 
    { 
        //This will use the standard timelimit 
        if (!$this->sendCommand('DATA', 'DATA', 354)) { 
            return false; 
        } 
 
        /* The server is ready to accept data! 
         * According to rfc821 we should not send more than 1000 characters on a single line (including the LE) 
         * so we will break the data up into lines by 
 and/or 
 then if needed we will break each of those into 
         * smaller lines to fit within the limit. 
         * We will also look for lines that start with a '.' and prepend an additional '.'. 
         * NOTE: this does not count towards line-length limit. 
         */ 
 
        //Normalize line breaks before exploding 
        $lines = explode("
", str_replace(["
", "
"], "
", $msg_data)); 
 
        /* To distinguish between a complete RFC822 message and a plain message body, we check if the first field 
         * of the first line (':' separated) does not contain a space then it _should_ be a header and we will 
         * process all lines before a blank line as headers. 
         */ 
 
        $field = substr($lines[0], 0, strpos($lines[0], ':')); 
        $in_headers = false; 
        if (!empty($field) && strpos($field, ' ') === false) { 
            $in_headers = true; 
        } 
 
        foreach ($lines as $line) { 
            $lines_out = []; 
            if ($in_headers && $line === '') { 
                $in_headers = false; 
            } 
            //Break this line up into several smaller lines if it's too long 
            //Micro-optimisation: isset($str[$len]) is faster than (strlen($str) > $len), 
            while (isset($line[self::MAX_LINE_LENGTH])) { 
                //Working backwards, try to find a space within the last MAX_LINE_LENGTH chars of the line to break on 
                //so as to avoid breaking in the middle of a word 
                $pos = strrpos(substr($line, 0, self::MAX_LINE_LENGTH), ' '); 
                //Deliberately matches both false and 0 
                if (!$pos) { 
                    //No nice break found, add a hard break 
                    $pos = self::MAX_LINE_LENGTH - 1; 
                    $lines_out[] = substr($line, 0, $pos); 
                    $line = substr($line, $pos); 
                } else { 
                    //Break at the found point 
                    $lines_out[] = substr($line, 0, $pos); 
                    //Move along by the amount we dealt with 
                    $line = substr($line, $pos + 1); 
                } 
                //If processing headers add a LWSP-char to the front of new line RFC822 section 3.1.1 
                if ($in_headers) { 
                    $line = "	" . $line; 
                } 
            } 
            $lines_out[] = $line; 
 
            //Send the lines to the server 
            foreach ($lines_out as $line_out) { 
                //Dot-stuffing as per RFC5321 section 4.5.2 
                //https://tools.ietf.org/html/rfc5321#section-4.5.2 
                if (!empty($line_out) && $line_out[0] === '.') { 
                    $line_out = '.' . $line_out; 
                } 
                $this->client_send($line_out . static::LE, 'DATA'); 
            } 
        } 
 
        //Message data has been sent, complete the command 
        //Increase timelimit for end of DATA command 
        $savetimelimit = $this->Timelimit; 
        $this->Timelimit *= 2; 
        $result = $this->sendCommand('DATA END', '.', 250); 
        $this->recordLastTransactionID(); 
        //Restore timelimit 
        $this->Timelimit = $savetimelimit; 
 
        return $result; 
    } 
 
    /** 
     * Send an SMTP HELO or EHLO command. 
     * Used to identify the sending server to the receiving server. 
     * This makes sure that client and server are in a known state. 
     * Implements RFC 821: HELO <SP> <domain> <CRLF> 
     * and RFC 2821 EHLO. 
     * 
     * @param string $host The host name or IP to connect to 
     * 
     * @return bool 
     */ 
    public function hello($host = '') 
    { 
        //Try extended hello first (RFC 2821) 
        if ($this->sendHello('EHLO', $host)) { 
            return true; 
        } 
 
        //Some servers shut down the SMTP service here (RFC 5321) 
        if (substr($this->helo_rply, 0, 3) == '421') { 
            return false; 
        } 
 
        return $this->sendHello('HELO', $host); 
    } 
 
    /** 
     * Send an SMTP HELO or EHLO command. 
     * Low-level implementation used by hello(). 
     * 
     * @param string $hello The HELO string 
     * @param string $host  The hostname to say we are 
     * 
     * @return bool 
     * 
     * @see hello() 
     */ 
    protected function sendHello($hello, $host) 
    { 
        $noerror = $this->sendCommand($hello, $hello . ' ' . $host, 250); 
        $this->helo_rply = $this->last_reply; 
        if ($noerror) { 
            $this->parseHelloFields($hello); 
        } else { 
            $this->server_caps = null; 
        } 
 
        return $noerror; 
    } 
 
    /** 
     * Parse a reply to HELO/EHLO command to discover server extensions. 
     * In case of HELO, the only parameter that can be discovered is a server name. 
     * 
     * @param string $type `HELO` or `EHLO` 
     */ 
    protected function parseHelloFields($type) 
    { 
        $this->server_caps = []; 
        $lines = explode("
", $this->helo_rply); 
 
        foreach ($lines as $n => $s) { 
            //First 4 chars contain response code followed by - or space 
            $s = trim(substr($s, 4)); 
            if (empty($s)) { 
                continue; 
            } 
            $fields = explode(' ', $s); 
            if (!empty($fields)) { 
                if (!$n) { 
                    $name = $type; 
                    $fields = $fields[0]; 
                } else { 
                    $name = array_shift($fields); 
                    switch ($name) { 
                        case 'SIZE': 
                            $fields = ($fields ? $fields[0] : 0); 
                            break; 
                        case 'AUTH': 
                            if (!is_array($fields)) { 
                                $fields = []; 
                            } 
                            break; 
                        default: 
                            $fields = true; 
                    } 
                } 
                $this->server_caps[$name] = $fields; 
            } 
        } 
    } 
 
    /** 
     * Send an SMTP MAIL command. 
     * Starts a mail transaction from the email address specified in 
     * $from. Returns true if successful or false otherwise. If True 
     * the mail transaction is started and then one or more recipient 
     * commands may be called followed by a data command. 
     * Implements RFC 821: MAIL <SP> FROM:<reverse-path> <CRLF>. 
     * 
     * @param string $from Source address of this message 
     * 
     * @return bool 
     */ 
    public function mail($from) 
    { 
        $useVerp = ($this->do_verp ? ' XVERP' : ''); 
 
        return $this->sendCommand( 
            'MAIL FROM', 
            'MAIL FROM:<' . $from . '>' . $useVerp, 
            250 
        ); 
    } 
 
    /** 
     * Send an SMTP QUIT command. 
     * Closes the socket if there is no error or the $close_on_error argument is true. 
     * Implements from RFC 821: QUIT <CRLF>. 
     * 
     * @param bool $close_on_error Should the connection close if an error occurs? 
     * 
     * @return bool 
     */ 
    public function quit($close_on_error = true) 
    { 
        $noerror = $this->sendCommand('QUIT', 'QUIT', 221); 
        $err = $this->error; //Save any error 
        if ($noerror || $close_on_error) { 
            $this->close(); 
            $this->error = $err; //Restore any error from the quit command 
        } 
 
        return $noerror; 
    } 
 
    /** 
     * Send an SMTP RCPT command. 
     * Sets the TO argument to $toaddr. 
     * Returns true if the recipient was accepted false if it was rejected. 
     * Implements from RFC 821: RCPT <SP> TO:<forward-path> <CRLF>. 
     * 
     * @param string $address The address the message is being sent to 
     * @param string $dsn     Comma separated list of DSN notifications. NEVER, SUCCESS, FAILURE 
     *                        or DELAY. If you specify NEVER all other notifications are ignored. 
     * 
     * @return bool 
     */ 
    public function recipient($address, $dsn = '') 
    { 
        if (empty($dsn)) { 
            $rcpt = 'RCPT TO:<' . $address . '>'; 
        } else { 
            $dsn = strtoupper($dsn); 
            $notify = []; 
 
            if (strpos($dsn, 'NEVER') !== false) { 
                $notify[] = 'NEVER'; 
            } else { 
                foreach (['SUCCESS', 'FAILURE', 'DELAY'] as $value) { 
                    if (strpos($dsn, $value) !== false) { 
                        $notify[] = $value; 
                    } 
                } 
            } 
 
            $rcpt = 'RCPT TO:<' . $address . '> NOTIFY=' . implode(',', $notify); 
        } 
 
        return $this->sendCommand( 
            'RCPT TO', 
            $rcpt, 
            [250, 251] 
        ); 
    } 
 
    /** 
     * Send an SMTP RSET command. 
     * Abort any transaction that is currently in progress. 
     * Implements RFC 821: RSET <CRLF>. 
     * 
     * @return bool True on success 
     */ 
    public function reset() 
    { 
        return $this->sendCommand('RSET', 'RSET', 250); 
    } 
 
    /** 
     * Send a command to an SMTP server and check its return code. 
     * 
     * @param string    $command       The command name - not sent to the server 
     * @param string    $commandstring The actual command to send 
     * @param int|array $expect        One or more expected integer success codes 
     * 
     * @return bool True on success 
     */ 
    protected function sendCommand($command, $commandstring, $expect) 
    { 
        if (!$this->connected()) { 
            $this->setError("Called $command without being connected"); 
 
            return false; 
        } 
        //Reject line breaks in all commands 
        if ((strpos($commandstring, "
") !== false) || (strpos($commandstring, "
") !== false)) { 
            $this->setError("Command '$command' contained line breaks"); 
 
            return false; 
        } 
        $this->client_send($commandstring . static::LE, $command); 
 
        $this->last_reply = $this->get_lines(); 
        //Fetch SMTP code and possible error code explanation 
        $matches = []; 
        if (preg_match('/^([\d]{3})[ -](?:([\d]\.[\d]\.[\d]{1,2}) )?/', $this->last_reply, $matches)) { 
            $code = (int) $matches[1]; 
            $code_ex = (count($matches) > 2 ? $matches[2] : null); 
            //Cut off error code from each response line 
            $detail = preg_replace( 
                "/{$code}[ -]" . 
                ($code_ex ? str_replace('.', '\.', $code_ex) . ' ' : '') . '/m', 
                '', 
                $this->last_reply 
            ); 
        } else { 
            //Fall back to simple parsing if regex fails 
            $code = (int) substr($this->last_reply, 0, 3); 
            $code_ex = null; 
            $detail = substr($this->last_reply, 4); 
        } 
 
        $this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER); 
 
        if (!in_array($code, (array) $expect, true)) { 
            $this->setError( 
                "$command command failed", 
                $detail, 
                $code, 
                $code_ex 
            ); 
            $this->edebug( 
                'SMTP ERROR: ' . $this->error['error'] . ': ' . $this->last_reply, 
                self::DEBUG_CLIENT 
            ); 
 
            return false; 
        } 
 
        $this->setError(''); 
 
        return true; 
    } 
 
    /** 
     * Send an SMTP SAML command. 
     * Starts a mail transaction from the email address specified in $from. 
     * Returns true if successful or false otherwise. If True 
     * the mail transaction is started and then one or more recipient 
     * commands may be called followed by a data command. This command 
     * will send the message to the users terminal if they are logged 
     * in and send them an email. 
     * Implements RFC 821: SAML <SP> FROM:<reverse-path> <CRLF>. 
     * 
     * @param string $from The address the message is from 
     * 
     * @return bool 
     */ 
    public function sendAndMail($from) 
    { 
        return $this->sendCommand('SAML', "SAML FROM:$from", 250); 
    } 
 
    /** 
     * Send an SMTP VRFY command. 
     * 
     * @param string $name The name to verify 
     * 
     * @return bool 
     */ 
    public function verify($name) 
    { 
        return $this->sendCommand('VRFY', "VRFY $name", [250, 251]); 
    } 
 
    /** 
     * Send an SMTP NOOP command. 
     * Used to keep keep-alives alive, doesn't actually do anything. 
     * 
     * @return bool 
     */ 
    public function noop() 
    { 
        return $this->sendCommand('NOOP', 'NOOP', 250); 
    } 
 
    /** 
     * Send an SMTP TURN command. 
     * This is an optional command for SMTP that this class does not support. 
     * This method is here to make the RFC821 Definition complete for this class 
     * and _may_ be implemented in future. 
     * Implements from RFC 821: TURN <CRLF>. 
     * 
     * @return bool 
     */ 
    public function turn() 
    { 
        $this->setError('The SMTP TURN command is not implemented'); 
        $this->edebug('SMTP NOTICE: ' . $this->error['error'], self::DEBUG_CLIENT); 
 
        return false; 
    } 
 
    /** 
     * Send raw data to the server. 
     * 
     * @param string $data    The data to send 
     * @param string $command Optionally, the command this is part of, used only for controlling debug output 
     * 
     * @return int|bool The number of bytes sent to the server or false on error 
     */ 
    public function client_send($data, $command = '') 
    { 
        //If SMTP transcripts are left enabled, or debug output is posted online 
        //it can leak credentials, so hide credentials in all but lowest level 
        if ( 
            self::DEBUG_LOWLEVEL > $this->do_debug && 
            in_array($command, ['User & Password', 'Username', 'Password'], true) 
        ) { 
            $this->edebug('CLIENT -> SERVER: [credentials hidden]', self::DEBUG_CLIENT); 
        } else { 
            $this->edebug('CLIENT -> SERVER: ' . $data, self::DEBUG_CLIENT); 
        } 
        set_error_handler([$this, 'errorHandler']); 
        $result = fwrite($this->smtp_conn, $data); 
        restore_error_handler(); 
 
        return $result; 
    } 
 
    /** 
     * Get the latest error. 
     * 
     * @return array 
     */ 
    public function getError() 
    { 
        return $this->error; 
    } 
 
    /** 
     * Get SMTP extensions available on the server. 
     * 
     * @return array|null 
     */ 
    public function getServerExtList() 
    { 
        return $this->server_caps; 
    } 
 
    /** 
     * Get metadata about the SMTP server from its HELO/EHLO response. 
     * The method works in three ways, dependent on argument value and current state: 
     *   1. HELO/EHLO has not been sent - returns null and populates $this->error. 
     *   2. HELO has been sent - 
     *     $name == 'HELO': returns server name 
     *     $name == 'EHLO': returns boolean false 
     *     $name == any other string: returns null and populates $this->error 
     *   3. EHLO has been sent - 
     *     $name == 'HELO'|'EHLO': returns the server name 
     *     $name == any other string: if extension $name exists, returns True 
     *       or its options (e.g. AUTH mechanisms supported). Otherwise returns False. 
     * 
     * @param string $name Name of SMTP extension or 'HELO'|'EHLO' 
     * 
     * @return string|bool|null 
     */ 
    public function getServerExt($name) 
    { 
        if (!$this->server_caps) { 
            $this->setError('No HELO/EHLO was sent'); 
 
            return; 
        } 
 
        if (!array_key_exists($name, $this->server_caps)) { 
            if ('HELO' === $name) { 
                return $this->server_caps['EHLO']; 
            } 
            if ('EHLO' === $name || array_key_exists('EHLO', $this->server_caps)) { 
                return false; 
            } 
            $this->setError('HELO handshake was used; No information about server extensions available'); 
 
            return; 
        } 
 
        return $this->server_caps[$name]; 
    } 
 
    /** 
     * Get the last reply from the server. 
     * 
     * @return string 
     */ 
    public function getLastReply() 
    { 
        return $this->last_reply; 
    } 
 
    /** 
     * Read the SMTP server's response. 
     * Either before eof or socket timeout occurs on the operation. 
     * With SMTP we can tell if we have more lines to read if the 
     * 4th character is '-' symbol. If it is a space then we don't 
     * need to read anything else. 
     * 
     * @return string 
     */ 
    protected function get_lines() 
    { 
        //If the connection is bad, give up straight away 
        if (!is_resource($this->smtp_conn)) { 
            return ''; 
        } 
        $data = ''; 
        $endtime = 0; 
        stream_set_timeout($this->smtp_conn, $this->Timeout); 
        if ($this->Timelimit > 0) { 
            $endtime = time() + $this->Timelimit; 
        } 
        $selR = [$this->smtp_conn]; 
        $selW = null; 
        while (is_resource($this->smtp_conn) && !feof($this->smtp_conn)) { 
            //Must pass vars in here as params are by reference 
            //solution for signals inspired by https://github.com/symfony/symfony/pull/6540 
            set_error_handler([$this, 'errorHandler']); 
            $n = stream_select($selR, $selW, $selW, $this->Timelimit); 
            restore_error_handler(); 
 
            if ($n === false) { 
                $message = $this->getError()['detail']; 
 
                $this->edebug( 
                    'SMTP -> get_lines(): select failed (' . $message . ')', 
                    self::DEBUG_LOWLEVEL 
                ); 
 
                //stream_select returns false when the `select` system call is interrupted 
                //by an incoming signal, try the select again 
                if (stripos($message, 'interrupted system call') !== false) { 
                    $this->edebug( 
                        'SMTP -> get_lines(): retrying stream_select', 
                        self::DEBUG_LOWLEVEL 
                    ); 
                    $this->setError(''); 
                    continue; 
                } 
 
                break; 
            } 
 
            if (!$n) { 
                $this->edebug( 
                    'SMTP -> get_lines(): select timed-out in (' . $this->Timelimit . ' sec)', 
                    self::DEBUG_LOWLEVEL 
                ); 
                break; 
            } 
 
            //Deliberate noise suppression - errors are handled afterwards 
            $str = @fgets($this->smtp_conn, self::MAX_REPLY_LENGTH); 
            $this->edebug('SMTP INBOUND: "' . trim($str) . '"', self::DEBUG_LOWLEVEL); 
            $data .= $str; 
            //If response is only 3 chars (not valid, but RFC5321 S4.2 says it must be handled), 
            //or 4th character is a space or a line break char, we are done reading, break the loop. 
            //String array access is a significant micro-optimisation over strlen 
            if (!isset($str[3]) || $str[3] === ' ' || $str[3] === "
" || $str[3] === "
") { 
                break; 
            } 
            //Timed-out? Log and break 
            $info = stream_get_meta_data($this->smtp_conn); 
            if ($info['timed_out']) { 
                $this->edebug( 
                    'SMTP -> get_lines(): stream timed-out (' . $this->Timeout . ' sec)', 
                    self::DEBUG_LOWLEVEL 
                ); 
                break; 
            } 
            //Now check if reads took too long 
            if ($endtime && time() > $endtime) { 
                $this->edebug( 
                    'SMTP -> get_lines(): timelimit reached (' . 
                    $this->Timelimit . ' sec)', 
                    self::DEBUG_LOWLEVEL 
                ); 
                break; 
            } 
        } 
 
        return $data; 
    } 
 
    /** 
     * Enable or disable VERP address generation. 
     * 
     * @param bool $enabled 
     */ 
    public function setVerp($enabled = false) 
    { 
        $this->do_verp = $enabled; 
    } 
 
    /** 
     * Get VERP address generation mode. 
     * 
     * @return bool 
     */ 
    public function getVerp() 
    { 
        return $this->do_verp; 
    } 
 
    /** 
     * Set error messages and codes. 
     * 
     * @param string $message      The error message 
     * @param string $detail       Further detail on the error 
     * @param string $smtp_code    An associated SMTP error code 
     * @param string $smtp_code_ex Extended SMTP code 
     */ 
    protected function setError($message, $detail = '', $smtp_code = '', $smtp_code_ex = '') 
    { 
        $this->error = [ 
            'error' => $message, 
            'detail' => $detail, 
            'smtp_code' => $smtp_code, 
            'smtp_code_ex' => $smtp_code_ex, 
        ]; 
    } 
 
    /** 
     * Set debug output method. 
     * 
     * @param string|callable $method The name of the mechanism to use for debugging output, or a callable to handle it 
     */ 
    public function setDebugOutput($method = 'echo') 
    { 
        $this->Debugoutput = $method; 
    } 
 
    /** 
     * Get debug output method. 
     * 
     * @return string 
     */ 
    public function getDebugOutput() 
    { 
        return $this->Debugoutput; 
    } 
 
    /** 
     * Set debug output level. 
     * 
     * @param int $level 
     */ 
    public function setDebugLevel($level = 0) 
    { 
        $this->do_debug = $level; 
    } 
 
    /** 
     * Get debug output level. 
     * 
     * @return int 
     */ 
    public function getDebugLevel() 
    { 
        return $this->do_debug; 
    } 
 
    /** 
     * Set SMTP timeout. 
     * 
     * @param int $timeout The timeout duration in seconds 
     */ 
    public function setTimeout($timeout = 0) 
    { 
        $this->Timeout = $timeout; 
    } 
 
    /** 
     * Get SMTP timeout. 
     * 
     * @return int 
     */ 
    public function getTimeout() 
    { 
        return $this->Timeout; 
    } 
 
    /** 
     * Reports an error number and string. 
     * 
     * @param int    $errno   The error number returned by PHP 
     * @param string $errmsg  The error message returned by PHP 
     * @param string $errfile The file the error occurred in 
     * @param int    $errline The line number the error occurred on 
     */ 
    protected function errorHandler($errno, $errmsg, $errfile = '', $errline = 0) 
    { 
        $notice = 'Connection failed.'; 
        $this->setError( 
            $notice, 
            $errmsg, 
            (string) $errno 
        ); 
        $this->edebug( 
            "$notice Error #$errno: $errmsg [$errfile line $errline]", 
            self::DEBUG_CONNECTION 
        ); 
    } 
 
    /** 
     * Extract and return the ID of the last SMTP transaction based on 
     * a list of patterns provided in SMTP::$smtp_transaction_id_patterns. 
     * Relies on the host providing the ID in response to a DATA command. 
     * If no reply has been received yet, it will return null. 
     * If no pattern was matched, it will return false. 
     * 
     * @return bool|string|null 
     */ 
    protected function recordLastTransactionID() 
    { 
        $reply = $this->getLastReply(); 
 
        if (empty($reply)) { 
            $this->last_smtp_transaction_id = null; 
        } else { 
            $this->last_smtp_transaction_id = false; 
            foreach ($this->smtp_transaction_id_patterns as $smtp_transaction_id_pattern) { 
                $matches = []; 
                if (preg_match($smtp_transaction_id_pattern, $reply, $matches)) { 
                    $this->last_smtp_transaction_id = trim($matches[1]); 
                    break; 
                } 
            } 
        } 
 
        return $this->last_smtp_transaction_id; 
    } 
 
    /** 
     * Get the queue/transaction ID of the last SMTP transaction 
     * If no reply has been received yet, it will return null. 
     * If no pattern was matched, it will return false. 
     * 
     * @return bool|string|null 
     * 
     * @see recordLastTransactionID() 
     */ 
    public function getLastTransactionID() 
    { 
        return $this->last_smtp_transaction_id; 
    } 
} 
 ?>

Did this file decode correctly?

Original Code

<?php

/**
 * PHPMailer RFC821 SMTP email transport class.
 * PHP Version 5.5.
 *
 * @see       https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
 *
 * @author    Marcus Bointon (Synchro/coolbru) <[email protected]>
 * @author    Jim Jagielski (jimjag) <[email protected]>
 * @author    Andy Prevost (codeworxtech) <[email protected]>
 * @author    Brent R. Matzelle (original founder)
 * @copyright 2012 - 2020 Marcus Bointon
 * @copyright 2010 - 2012 Jim Jagielski
 * @copyright 2004 - 2009 Andy Prevost
 * @license   http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 * @note      This program is distributed in the hope that it will be useful - WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.
 */

namespace PHPMailer\PHPMailer;

/**
 * PHPMailer RFC821 SMTP email transport class.
 * Implements RFC 821 SMTP commands and provides some utility methods for sending mail to an SMTP server.
 *
 * @author Chris Ryan
 * @author Marcus Bointon <[email protected]>
 */
class SMTP
{
    /**
     * The PHPMailer SMTP version number.
     *
     * @var string
     */
    const VERSION = '6.5.1';

    /**
     * SMTP line break constant.
     *
     * @var string
     */
    const LE = "\r\n";

    /**
     * The SMTP port to use if one is not specified.
     *
     * @var int
     */
    const DEFAULT_PORT = 25;

    /**
     * The maximum line length allowed by RFC 5321 section 4.5.3.1.6,
     * *excluding* a trailing CRLF break.
     *
     * @see https://tools.ietf.org/html/rfc5321#section-4.5.3.1.6
     *
     * @var int
     */
    const MAX_LINE_LENGTH = 998;

    /**
     * The maximum line length allowed for replies in RFC 5321 section 4.5.3.1.5,
     * *including* a trailing CRLF line break.
     *
     * @see https://tools.ietf.org/html/rfc5321#section-4.5.3.1.5
     *
     * @var int
     */
    const MAX_REPLY_LENGTH = 512;

    /**
     * Debug level for no output.
     *
     * @var int
     */
    const DEBUG_OFF = 0;

    /**
     * Debug level to show client -> server messages.
     *
     * @var int
     */
    const DEBUG_CLIENT = 1;

    /**
     * Debug level to show client -> server and server -> client messages.
     *
     * @var int
     */
    const DEBUG_SERVER = 2;

    /**
     * Debug level to show connection status, client -> server and server -> client messages.
     *
     * @var int
     */
    const DEBUG_CONNECTION = 3;

    /**
     * Debug level to show all messages.
     *
     * @var int
     */
    const DEBUG_LOWLEVEL = 4;

    /**
     * Debug output level.
     * Options:
     * * self::DEBUG_OFF (`0`) No debug output, default
     * * self::DEBUG_CLIENT (`1`) Client commands
     * * self::DEBUG_SERVER (`2`) Client commands and server responses
     * * self::DEBUG_CONNECTION (`3`) As DEBUG_SERVER plus connection status
     * * self::DEBUG_LOWLEVEL (`4`) Low-level data output, all messages.
     *
     * @var int
     */
    public $do_debug = self::DEBUG_OFF;

    /**
     * How to handle debug output.
     * Options:
     * * `echo` Output plain-text as-is, appropriate for CLI
     * * `html` Output escaped, line breaks converted to `<br>`, appropriate for browser output
     * * `error_log` Output to error log as configured in php.ini
     * Alternatively, you can provide a callable expecting two params: a message string and the debug level:
     *
     * ```php
     * $smtp->Debugoutput = function($str, $level) {echo "debug level $level; message: $str";};
     * ```
     *
     * Alternatively, you can pass in an instance of a PSR-3 compatible logger, though only `debug`
     * level output is used:
     *
     * ```php
     * $mail->Debugoutput = new myPsr3Logger;
     * ```
     *
     * @var string|callable|\Psr\Log\LoggerInterface
     */
    public $Debugoutput = 'echo';

    /**
     * Whether to use VERP.
     *
     * @see http://en.wikipedia.org/wiki/Variable_envelope_return_path
     * @see http://www.postfix.org/VERP_README.html Info on VERP
     *
     * @var bool
     */
    public $do_verp = false;

    /**
     * The timeout value for connection, in seconds.
     * Default of 5 minutes (300sec) is from RFC2821 section 4.5.3.2.
     * This needs to be quite high to function correctly with hosts using greetdelay as an anti-spam measure.
     *
     * @see http://tools.ietf.org/html/rfc2821#section-4.5.3.2
     *
     * @var int
     */
    public $Timeout = 300;

    /**
     * How long to wait for commands to complete, in seconds.
     * Default of 5 minutes (300sec) is from RFC2821 section 4.5.3.2.
     *
     * @var int
     */
    public $Timelimit = 300;

    /**
     * Patterns to extract an SMTP transaction id from reply to a DATA command.
     * The first capture group in each regex will be used as the ID.
     * MS ESMTP returns the message ID, which may not be correct for internal tracking.
     *
     * @var string[]
     */
    protected $smtp_transaction_id_patterns = [
        'exim' => '/[\d]{3} OK id=(.*)/',
        'sendmail' => '/[\d]{3} 2.0.0 (.*) Message/',
        'postfix' => '/[\d]{3} 2.0.0 Ok: queued as (.*)/',
        'Microsoft_ESMTP' => '/[0-9]{3} 2.[\d].0 (.*)@(?:.*) Queued mail for delivery/',
        'Amazon_SES' => '/[\d]{3} Ok (.*)/',
        'SendGrid' => '/[\d]{3} Ok: queued as (.*)/',
        'CampaignMonitor' => '/[\d]{3} 2.0.0 OK:([a-zA-Z\d]{48})/',
        'Haraka' => '/[\d]{3} Message Queued \((.*)\)/',
    ];

    /**
     * The last transaction ID issued in response to a DATA command,
     * if one was detected.
     *
     * @var string|bool|null
     */
    protected $last_smtp_transaction_id;

    /**
     * The socket for the server connection.
     *
     * @var ?resource
     */
    protected $smtp_conn;

    /**
     * Error information, if any, for the last SMTP command.
     *
     * @var array
     */
    protected $error = [
        'error' => '',
        'detail' => '',
        'smtp_code' => '',
        'smtp_code_ex' => '',
    ];

    /**
     * The reply the server sent to us for HELO.
     * If null, no HELO string has yet been received.
     *
     * @var string|null
     */
    protected $helo_rply;

    /**
     * The set of SMTP extensions sent in reply to EHLO command.
     * Indexes of the array are extension names.
     * Value at index 'HELO' or 'EHLO' (according to command that was sent)
     * represents the server name. In case of HELO it is the only element of the array.
     * Other values can be boolean TRUE or an array containing extension options.
     * If null, no HELO/EHLO string has yet been received.
     *
     * @var array|null
     */
    protected $server_caps;

    /**
     * The most recent reply received from the server.
     *
     * @var string
     */
    protected $last_reply = '';

    /**
     * Output debugging info via a user-selected method.
     *
     * @param string $str   Debug string to output
     * @param int    $level The debug level of this message; see DEBUG_* constants
     *
     * @see SMTP::$Debugoutput
     * @see SMTP::$do_debug
     */
    protected function edebug($str, $level = 0)
    {
        if ($level > $this->do_debug) {
            return;
        }
        //Is this a PSR-3 logger?
        if ($this->Debugoutput instanceof \Psr\Log\LoggerInterface) {
            $this->Debugoutput->debug($str);

            return;
        }
        //Avoid clash with built-in function names
        if (is_callable($this->Debugoutput) && !in_array($this->Debugoutput, ['error_log', 'html', 'echo'])) {
            call_user_func($this->Debugoutput, $str, $level);

            return;
        }
        switch ($this->Debugoutput) {
            case 'error_log':
                //Don't output, just log
                error_log($str);
                break;
            case 'html':
                //Cleans up output a bit for a better looking, HTML-safe output
                echo gmdate('Y-m-d H:i:s'), ' ', htmlentities(
                    preg_replace('/[\r\n]+/', '', $str),
                    ENT_QUOTES,
                    'UTF-8'
                ), "<br>\n";
                break;
            case 'echo':
            default:
                //Normalize line breaks
                $str = preg_replace('/\r\n|\r/m', "\n", $str);
                echo gmdate('Y-m-d H:i:s'),
                "\t",
                    //Trim trailing space
                trim(
                    //Indent for readability, except for trailing break
                    str_replace(
                        "\n",
                        "\n                   \t                  ",
                        trim($str)
                    )
                ),
                "\n";
        }
    }

    /**
     * Connect to an SMTP server.
     *
     * @param string $host    SMTP server IP or host name
     * @param int    $port    The port number to connect to
     * @param int    $timeout How long to wait for the connection to open
     * @param array  $options An array of options for stream_context_create()
     *
     * @return bool
     */
    public function connect($host, $port = null, $timeout = 30, $options = [])
    {
        //Clear errors to avoid confusion
        $this->setError('');
        //Make sure we are __not__ connected
        if ($this->connected()) {
            //Already connected, generate error
            $this->setError('Already connected to a server');

            return false;
        }
        if (empty($port)) {
            $port = self::DEFAULT_PORT;
        }
        //Connect to the SMTP server
        $this->edebug(
            "Connection: opening to $host:$port, timeout=$timeout, options=" .
            (count($options) > 0 ? var_export($options, true) : 'array()'),
            self::DEBUG_CONNECTION
        );

        $this->smtp_conn = $this->getSMTPConnection($host, $port, $timeout, $options);

        if ($this->smtp_conn === false) {
            //Error info already set inside `getSMTPConnection()`
            return false;
        }

        $this->edebug('Connection: opened', self::DEBUG_CONNECTION);

        //Get any announcement
        $this->last_reply = $this->get_lines();
        $this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER);
        $responseCode = (int)substr($this->last_reply, 0, 3);
        if ($responseCode === 220) {
            return true;
        }
        //Anything other than a 220 response means something went wrong
        //RFC 5321 says the server will wait for us to send a QUIT in response to a 554 error
        //https://tools.ietf.org/html/rfc5321#section-3.1
        if ($responseCode === 554) {
            $this->quit();
        }
        //This will handle 421 responses which may not wait for a QUIT (e.g. if the server is being shut down)
        $this->edebug('Connection: closing due to error', self::DEBUG_CONNECTION);
        $this->close();
        return false;
    }

    /**
     * Create connection to the SMTP server.
     *
     * @param string $host    SMTP server IP or host name
     * @param int    $port    The port number to connect to
     * @param int    $timeout How long to wait for the connection to open
     * @param array  $options An array of options for stream_context_create()
     *
     * @return false|resource
     */
    protected function getSMTPConnection($host, $port = null, $timeout = 30, $options = [])
    {
        static $streamok;
        //This is enabled by default since 5.0.0 but some providers disable it
        //Check this once and cache the result
        if (null === $streamok) {
            $streamok = function_exists('stream_socket_client');
        }

        $errno = 0;
        $errstr = '';
        if ($streamok) {
            $socket_context = stream_context_create($options);
            set_error_handler([$this, 'errorHandler']);
            $connection = stream_socket_client(
                $host . ':' . $port,
                $errno,
                $errstr,
                $timeout,
                STREAM_CLIENT_CONNECT,
                $socket_context
            );
            restore_error_handler();
        } else {
            //Fall back to fsockopen which should work in more places, but is missing some features
            $this->edebug(
                'Connection: stream_socket_client not available, falling back to fsockopen',
                self::DEBUG_CONNECTION
            );
            set_error_handler([$this, 'errorHandler']);
            $connection = fsockopen(
                $host,
                $port,
                $errno,
                $errstr,
                $timeout
            );
            restore_error_handler();
        }

        //Verify we connected properly
        if (!is_resource($connection)) {
            $this->setError(
                'Failed to connect to server',
                '',
                (string) $errno,
                $errstr
            );
            $this->edebug(
                'SMTP ERROR: ' . $this->error['error']
                . ": $errstr ($errno)",
                self::DEBUG_CLIENT
            );

            return false;
        }

        //SMTP server can take longer to respond, give longer timeout for first read
        //Windows does not have support for this timeout function
        if (strpos(PHP_OS, 'WIN') !== 0) {
            $max = (int)ini_get('max_execution_time');
            //Don't bother if unlimited, or if set_time_limit is disabled
            if (0 !== $max && $timeout > $max && strpos(ini_get('disable_functions'), 'set_time_limit') === false) {
                @set_time_limit($timeout);
            }
            stream_set_timeout($connection, $timeout, 0);
        }

        return $connection;
    }

    /**
     * Initiate a TLS (encrypted) session.
     *
     * @return bool
     */
    public function startTLS()
    {
        if (!$this->sendCommand('STARTTLS', 'STARTTLS', 220)) {
            return false;
        }

        //Allow the best TLS version(s) we can
        $crypto_method = STREAM_CRYPTO_METHOD_TLS_CLIENT;

        //PHP 5.6.7 dropped inclusion of TLS 1.1 and 1.2 in STREAM_CRYPTO_METHOD_TLS_CLIENT
        //so add them back in manually if we can
        if (defined('STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT')) {
            $crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT;
            $crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT;
        }

        //Begin encrypted connection
        set_error_handler([$this, 'errorHandler']);
        $crypto_ok = stream_socket_enable_crypto(
            $this->smtp_conn,
            true,
            $crypto_method
        );
        restore_error_handler();

        return (bool) $crypto_ok;
    }

    /**
     * Perform SMTP authentication.
     * Must be run after hello().
     *
     * @see    hello()
     *
     * @param string $username The user name
     * @param string $password The password
     * @param string $authtype The auth type (CRAM-MD5, PLAIN, LOGIN, XOAUTH2)
     * @param OAuth  $OAuth    An optional OAuth instance for XOAUTH2 authentication
     *
     * @return bool True if successfully authenticated
     */
    public function authenticate(
        $username,
        $password,
        $authtype = null,
        $OAuth = null
    ) {
        if (!$this->server_caps) {
            $this->setError('Authentication is not allowed before HELO/EHLO');

            return false;
        }

        if (array_key_exists('EHLO', $this->server_caps)) {
            //SMTP extensions are available; try to find a proper authentication method
            if (!array_key_exists('AUTH', $this->server_caps)) {
                $this->setError('Authentication is not allowed at this stage');
                //'at this stage' means that auth may be allowed after the stage changes
                //e.g. after STARTTLS

                return false;
            }

            $this->edebug('Auth method requested: ' . ($authtype ?: 'UNSPECIFIED'), self::DEBUG_LOWLEVEL);
            $this->edebug(
                'Auth methods available on the server: ' . implode(',', $this->server_caps['AUTH']),
                self::DEBUG_LOWLEVEL
            );

            //If we have requested a specific auth type, check the server supports it before trying others
            if (null !== $authtype && !in_array($authtype, $this->server_caps['AUTH'], true)) {
                $this->edebug('Requested auth method not available: ' . $authtype, self::DEBUG_LOWLEVEL);
                $authtype = null;
            }

            if (empty($authtype)) {
                //If no auth mechanism is specified, attempt to use these, in this order
                //Try CRAM-MD5 first as it's more secure than the others
                foreach (['CRAM-MD5', 'LOGIN', 'PLAIN', 'XOAUTH2'] as $method) {
                    if (in_array($method, $this->server_caps['AUTH'], true)) {
                        $authtype = $method;
                        break;
                    }
                }
                if (empty($authtype)) {
                    $this->setError('No supported authentication methods found');

                    return false;
                }
                $this->edebug('Auth method selected: ' . $authtype, self::DEBUG_LOWLEVEL);
            }

            if (!in_array($authtype, $this->server_caps['AUTH'], true)) {
                $this->setError("The requested authentication method \"$authtype\" is not supported by the server");

                return false;
            }
        } elseif (empty($authtype)) {
            $authtype = 'LOGIN';
        }
        switch ($authtype) {
            case 'PLAIN':
                //Start authentication
                if (!$this->sendCommand('AUTH', 'AUTH PLAIN', 334)) {
                    return false;
                }
                //Send encoded username and password
                if (
                    //Format from https://tools.ietf.org/html/rfc4616#section-2
                    //We skip the first field (it's forgery), so the string starts with a null byte
                    !$this->sendCommand(
                        'User & Password',
                        base64_encode("\0" . $username . "\0" . $password),
                        235
                    )
                ) {
                    return false;
                }
                break;
            case 'LOGIN':
                //Start authentication
                if (!$this->sendCommand('AUTH', 'AUTH LOGIN', 334)) {
                    return false;
                }
                if (!$this->sendCommand('Username', base64_encode($username), 334)) {
                    return false;
                }
                if (!$this->sendCommand('Password', base64_encode($password), 235)) {
                    return false;
                }
                break;
            case 'CRAM-MD5':
                //Start authentication
                if (!$this->sendCommand('AUTH CRAM-MD5', 'AUTH CRAM-MD5', 334)) {
                    return false;
                }
                //Get the challenge
                $challenge = base64_decode(substr($this->last_reply, 4));

                //Build the response
                $response = $username . ' ' . $this->hmac($challenge, $password);

                //send encoded credentials
                return $this->sendCommand('Username', base64_encode($response), 235);
            case 'XOAUTH2':
                //The OAuth instance must be set up prior to requesting auth.
                if (null === $OAuth) {
                    return false;
                }
                $oauth = $OAuth->getOauth64();

                //Start authentication
                if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2 ' . $oauth, 235)) {
                    return false;
                }
                break;
            default:
                $this->setError("Authentication method \"$authtype\" is not supported");

                return false;
        }

        return true;
    }

    /**
     * Calculate an MD5 HMAC hash.
     * Works like hash_hmac('md5', $data, $key)
     * in case that function is not available.
     *
     * @param string $data The data to hash
     * @param string $key  The key to hash with
     *
     * @return string
     */
    protected function hmac($data, $key)
    {
        if (function_exists('hash_hmac')) {
            return hash_hmac('md5', $data, $key);
        }

        //The following borrowed from
        //http://php.net/manual/en/function.mhash.php#27225

        //RFC 2104 HMAC implementation for php.
        //Creates an md5 HMAC.
        //Eliminates the need to install mhash to compute a HMAC
        //by Lance Rushing

        $bytelen = 64; //byte length for md5
        if (strlen($key) > $bytelen) {
            $key = pack('H*', md5($key));
        }
        $key = str_pad($key, $bytelen, chr(0x00));
        $ipad = str_pad('', $bytelen, chr(0x36));
        $opad = str_pad('', $bytelen, chr(0x5c));
        $k_ipad = $key ^ $ipad;
        $k_opad = $key ^ $opad;

        return md5($k_opad . pack('H*', md5($k_ipad . $data)));
    }

    /**
     * Check connection state.
     *
     * @return bool True if connected
     */
    public function connected()
    {
        if (is_resource($this->smtp_conn)) {
            $sock_status = stream_get_meta_data($this->smtp_conn);
            if ($sock_status['eof']) {
                //The socket is valid but we are not connected
                $this->edebug(
                    'SMTP NOTICE: EOF caught while checking if connected',
                    self::DEBUG_CLIENT
                );
                $this->close();

                return false;
            }

            return true; //everything looks good
        }

        return false;
    }

    /**
     * Close the socket and clean up the state of the class.
     * Don't use this function without first trying to use QUIT.
     *
     * @see quit()
     */
    public function close()
    {
        $this->setError('');
        $this->server_caps = null;
        $this->helo_rply = null;
        if (is_resource($this->smtp_conn)) {
            //Close the connection and cleanup
            fclose($this->smtp_conn);
            $this->smtp_conn = null; //Makes for cleaner serialization
            $this->edebug('Connection: closed', self::DEBUG_CONNECTION);
        }
    }

    /**
     * Send an SMTP DATA command.
     * Issues a data command and sends the msg_data to the server,
     * finializing the mail transaction. $msg_data is the message
     * that is to be send with the headers. Each header needs to be
     * on a single line followed by a <CRLF> with the message headers
     * and the message body being separated by an additional <CRLF>.
     * Implements RFC 821: DATA <CRLF>.
     *
     * @param string $msg_data Message data to send
     *
     * @return bool
     */
    public function data($msg_data)
    {
        //This will use the standard timelimit
        if (!$this->sendCommand('DATA', 'DATA', 354)) {
            return false;
        }

        /* The server is ready to accept data!
         * According to rfc821 we should not send more than 1000 characters on a single line (including the LE)
         * so we will break the data up into lines by \r and/or \n then if needed we will break each of those into
         * smaller lines to fit within the limit.
         * We will also look for lines that start with a '.' and prepend an additional '.'.
         * NOTE: this does not count towards line-length limit.
         */

        //Normalize line breaks before exploding
        $lines = explode("\n", str_replace(["\r\n", "\r"], "\n", $msg_data));

        /* To distinguish between a complete RFC822 message and a plain message body, we check if the first field
         * of the first line (':' separated) does not contain a space then it _should_ be a header and we will
         * process all lines before a blank line as headers.
         */

        $field = substr($lines[0], 0, strpos($lines[0], ':'));
        $in_headers = false;
        if (!empty($field) && strpos($field, ' ') === false) {
            $in_headers = true;
        }

        foreach ($lines as $line) {
            $lines_out = [];
            if ($in_headers && $line === '') {
                $in_headers = false;
            }
            //Break this line up into several smaller lines if it's too long
            //Micro-optimisation: isset($str[$len]) is faster than (strlen($str) > $len),
            while (isset($line[self::MAX_LINE_LENGTH])) {
                //Working backwards, try to find a space within the last MAX_LINE_LENGTH chars of the line to break on
                //so as to avoid breaking in the middle of a word
                $pos = strrpos(substr($line, 0, self::MAX_LINE_LENGTH), ' ');
                //Deliberately matches both false and 0
                if (!$pos) {
                    //No nice break found, add a hard break
                    $pos = self::MAX_LINE_LENGTH - 1;
                    $lines_out[] = substr($line, 0, $pos);
                    $line = substr($line, $pos);
                } else {
                    //Break at the found point
                    $lines_out[] = substr($line, 0, $pos);
                    //Move along by the amount we dealt with
                    $line = substr($line, $pos + 1);
                }
                //If processing headers add a LWSP-char to the front of new line RFC822 section 3.1.1
                if ($in_headers) {
                    $line = "\t" . $line;
                }
            }
            $lines_out[] = $line;

            //Send the lines to the server
            foreach ($lines_out as $line_out) {
                //Dot-stuffing as per RFC5321 section 4.5.2
                //https://tools.ietf.org/html/rfc5321#section-4.5.2
                if (!empty($line_out) && $line_out[0] === '.') {
                    $line_out = '.' . $line_out;
                }
                $this->client_send($line_out . static::LE, 'DATA');
            }
        }

        //Message data has been sent, complete the command
        //Increase timelimit for end of DATA command
        $savetimelimit = $this->Timelimit;
        $this->Timelimit *= 2;
        $result = $this->sendCommand('DATA END', '.', 250);
        $this->recordLastTransactionID();
        //Restore timelimit
        $this->Timelimit = $savetimelimit;

        return $result;
    }

    /**
     * Send an SMTP HELO or EHLO command.
     * Used to identify the sending server to the receiving server.
     * This makes sure that client and server are in a known state.
     * Implements RFC 821: HELO <SP> <domain> <CRLF>
     * and RFC 2821 EHLO.
     *
     * @param string $host The host name or IP to connect to
     *
     * @return bool
     */
    public function hello($host = '')
    {
        //Try extended hello first (RFC 2821)
        if ($this->sendHello('EHLO', $host)) {
            return true;
        }

        //Some servers shut down the SMTP service here (RFC 5321)
        if (substr($this->helo_rply, 0, 3) == '421') {
            return false;
        }

        return $this->sendHello('HELO', $host);
    }

    /**
     * Send an SMTP HELO or EHLO command.
     * Low-level implementation used by hello().
     *
     * @param string $hello The HELO string
     * @param string $host  The hostname to say we are
     *
     * @return bool
     *
     * @see hello()
     */
    protected function sendHello($hello, $host)
    {
        $noerror = $this->sendCommand($hello, $hello . ' ' . $host, 250);
        $this->helo_rply = $this->last_reply;
        if ($noerror) {
            $this->parseHelloFields($hello);
        } else {
            $this->server_caps = null;
        }

        return $noerror;
    }

    /**
     * Parse a reply to HELO/EHLO command to discover server extensions.
     * In case of HELO, the only parameter that can be discovered is a server name.
     *
     * @param string $type `HELO` or `EHLO`
     */
    protected function parseHelloFields($type)
    {
        $this->server_caps = [];
        $lines = explode("\n", $this->helo_rply);

        foreach ($lines as $n => $s) {
            //First 4 chars contain response code followed by - or space
            $s = trim(substr($s, 4));
            if (empty($s)) {
                continue;
            }
            $fields = explode(' ', $s);
            if (!empty($fields)) {
                if (!$n) {
                    $name = $type;
                    $fields = $fields[0];
                } else {
                    $name = array_shift($fields);
                    switch ($name) {
                        case 'SIZE':
                            $fields = ($fields ? $fields[0] : 0);
                            break;
                        case 'AUTH':
                            if (!is_array($fields)) {
                                $fields = [];
                            }
                            break;
                        default:
                            $fields = true;
                    }
                }
                $this->server_caps[$name] = $fields;
            }
        }
    }

    /**
     * Send an SMTP MAIL command.
     * Starts a mail transaction from the email address specified in
     * $from. Returns true if successful or false otherwise. If True
     * the mail transaction is started and then one or more recipient
     * commands may be called followed by a data command.
     * Implements RFC 821: MAIL <SP> FROM:<reverse-path> <CRLF>.
     *
     * @param string $from Source address of this message
     *
     * @return bool
     */
    public function mail($from)
    {
        $useVerp = ($this->do_verp ? ' XVERP' : '');

        return $this->sendCommand(
            'MAIL FROM',
            'MAIL FROM:<' . $from . '>' . $useVerp,
            250
        );
    }

    /**
     * Send an SMTP QUIT command.
     * Closes the socket if there is no error or the $close_on_error argument is true.
     * Implements from RFC 821: QUIT <CRLF>.
     *
     * @param bool $close_on_error Should the connection close if an error occurs?
     *
     * @return bool
     */
    public function quit($close_on_error = true)
    {
        $noerror = $this->sendCommand('QUIT', 'QUIT', 221);
        $err = $this->error; //Save any error
        if ($noerror || $close_on_error) {
            $this->close();
            $this->error = $err; //Restore any error from the quit command
        }

        return $noerror;
    }

    /**
     * Send an SMTP RCPT command.
     * Sets the TO argument to $toaddr.
     * Returns true if the recipient was accepted false if it was rejected.
     * Implements from RFC 821: RCPT <SP> TO:<forward-path> <CRLF>.
     *
     * @param string $address The address the message is being sent to
     * @param string $dsn     Comma separated list of DSN notifications. NEVER, SUCCESS, FAILURE
     *                        or DELAY. If you specify NEVER all other notifications are ignored.
     *
     * @return bool
     */
    public function recipient($address, $dsn = '')
    {
        if (empty($dsn)) {
            $rcpt = 'RCPT TO:<' . $address . '>';
        } else {
            $dsn = strtoupper($dsn);
            $notify = [];

            if (strpos($dsn, 'NEVER') !== false) {
                $notify[] = 'NEVER';
            } else {
                foreach (['SUCCESS', 'FAILURE', 'DELAY'] as $value) {
                    if (strpos($dsn, $value) !== false) {
                        $notify[] = $value;
                    }
                }
            }

            $rcpt = 'RCPT TO:<' . $address . '> NOTIFY=' . implode(',', $notify);
        }

        return $this->sendCommand(
            'RCPT TO',
            $rcpt,
            [250, 251]
        );
    }

    /**
     * Send an SMTP RSET command.
     * Abort any transaction that is currently in progress.
     * Implements RFC 821: RSET <CRLF>.
     *
     * @return bool True on success
     */
    public function reset()
    {
        return $this->sendCommand('RSET', 'RSET', 250);
    }

    /**
     * Send a command to an SMTP server and check its return code.
     *
     * @param string    $command       The command name - not sent to the server
     * @param string    $commandstring The actual command to send
     * @param int|array $expect        One or more expected integer success codes
     *
     * @return bool True on success
     */
    protected function sendCommand($command, $commandstring, $expect)
    {
        if (!$this->connected()) {
            $this->setError("Called $command without being connected");

            return false;
        }
        //Reject line breaks in all commands
        if ((strpos($commandstring, "\n") !== false) || (strpos($commandstring, "\r") !== false)) {
            $this->setError("Command '$command' contained line breaks");

            return false;
        }
        $this->client_send($commandstring . static::LE, $command);

        $this->last_reply = $this->get_lines();
        //Fetch SMTP code and possible error code explanation
        $matches = [];
        if (preg_match('/^([\d]{3})[ -](?:([\d]\\.[\d]\\.[\d]{1,2}) )?/', $this->last_reply, $matches)) {
            $code = (int) $matches[1];
            $code_ex = (count($matches) > 2 ? $matches[2] : null);
            //Cut off error code from each response line
            $detail = preg_replace(
                "/{$code}[ -]" .
                ($code_ex ? str_replace('.', '\\.', $code_ex) . ' ' : '') . '/m',
                '',
                $this->last_reply
            );
        } else {
            //Fall back to simple parsing if regex fails
            $code = (int) substr($this->last_reply, 0, 3);
            $code_ex = null;
            $detail = substr($this->last_reply, 4);
        }

        $this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER);

        if (!in_array($code, (array) $expect, true)) {
            $this->setError(
                "$command command failed",
                $detail,
                $code,
                $code_ex
            );
            $this->edebug(
                'SMTP ERROR: ' . $this->error['error'] . ': ' . $this->last_reply,
                self::DEBUG_CLIENT
            );

            return false;
        }

        $this->setError('');

        return true;
    }

    /**
     * Send an SMTP SAML command.
     * Starts a mail transaction from the email address specified in $from.
     * Returns true if successful or false otherwise. If True
     * the mail transaction is started and then one or more recipient
     * commands may be called followed by a data command. This command
     * will send the message to the users terminal if they are logged
     * in and send them an email.
     * Implements RFC 821: SAML <SP> FROM:<reverse-path> <CRLF>.
     *
     * @param string $from The address the message is from
     *
     * @return bool
     */
    public function sendAndMail($from)
    {
        return $this->sendCommand('SAML', "SAML FROM:$from", 250);
    }

    /**
     * Send an SMTP VRFY command.
     *
     * @param string $name The name to verify
     *
     * @return bool
     */
    public function verify($name)
    {
        return $this->sendCommand('VRFY', "VRFY $name", [250, 251]);
    }

    /**
     * Send an SMTP NOOP command.
     * Used to keep keep-alives alive, doesn't actually do anything.
     *
     * @return bool
     */
    public function noop()
    {
        return $this->sendCommand('NOOP', 'NOOP', 250);
    }

    /**
     * Send an SMTP TURN command.
     * This is an optional command for SMTP that this class does not support.
     * This method is here to make the RFC821 Definition complete for this class
     * and _may_ be implemented in future.
     * Implements from RFC 821: TURN <CRLF>.
     *
     * @return bool
     */
    public function turn()
    {
        $this->setError('The SMTP TURN command is not implemented');
        $this->edebug('SMTP NOTICE: ' . $this->error['error'], self::DEBUG_CLIENT);

        return false;
    }

    /**
     * Send raw data to the server.
     *
     * @param string $data    The data to send
     * @param string $command Optionally, the command this is part of, used only for controlling debug output
     *
     * @return int|bool The number of bytes sent to the server or false on error
     */
    public function client_send($data, $command = '')
    {
        //If SMTP transcripts are left enabled, or debug output is posted online
        //it can leak credentials, so hide credentials in all but lowest level
        if (
            self::DEBUG_LOWLEVEL > $this->do_debug &&
            in_array($command, ['User & Password', 'Username', 'Password'], true)
        ) {
            $this->edebug('CLIENT -> SERVER: [credentials hidden]', self::DEBUG_CLIENT);
        } else {
            $this->edebug('CLIENT -> SERVER: ' . $data, self::DEBUG_CLIENT);
        }
        set_error_handler([$this, 'errorHandler']);
        $result = fwrite($this->smtp_conn, $data);
        restore_error_handler();

        return $result;
    }

    /**
     * Get the latest error.
     *
     * @return array
     */
    public function getError()
    {
        return $this->error;
    }

    /**
     * Get SMTP extensions available on the server.
     *
     * @return array|null
     */
    public function getServerExtList()
    {
        return $this->server_caps;
    }

    /**
     * Get metadata about the SMTP server from its HELO/EHLO response.
     * The method works in three ways, dependent on argument value and current state:
     *   1. HELO/EHLO has not been sent - returns null and populates $this->error.
     *   2. HELO has been sent -
     *     $name == 'HELO': returns server name
     *     $name == 'EHLO': returns boolean false
     *     $name == any other string: returns null and populates $this->error
     *   3. EHLO has been sent -
     *     $name == 'HELO'|'EHLO': returns the server name
     *     $name == any other string: if extension $name exists, returns True
     *       or its options (e.g. AUTH mechanisms supported). Otherwise returns False.
     *
     * @param string $name Name of SMTP extension or 'HELO'|'EHLO'
     *
     * @return string|bool|null
     */
    public function getServerExt($name)
    {
        if (!$this->server_caps) {
            $this->setError('No HELO/EHLO was sent');

            return;
        }

        if (!array_key_exists($name, $this->server_caps)) {
            if ('HELO' === $name) {
                return $this->server_caps['EHLO'];
            }
            if ('EHLO' === $name || array_key_exists('EHLO', $this->server_caps)) {
                return false;
            }
            $this->setError('HELO handshake was used; No information about server extensions available');

            return;
        }

        return $this->server_caps[$name];
    }

    /**
     * Get the last reply from the server.
     *
     * @return string
     */
    public function getLastReply()
    {
        return $this->last_reply;
    }

    /**
     * Read the SMTP server's response.
     * Either before eof or socket timeout occurs on the operation.
     * With SMTP we can tell if we have more lines to read if the
     * 4th character is '-' symbol. If it is a space then we don't
     * need to read anything else.
     *
     * @return string
     */
    protected function get_lines()
    {
        //If the connection is bad, give up straight away
        if (!is_resource($this->smtp_conn)) {
            return '';
        }
        $data = '';
        $endtime = 0;
        stream_set_timeout($this->smtp_conn, $this->Timeout);
        if ($this->Timelimit > 0) {
            $endtime = time() + $this->Timelimit;
        }
        $selR = [$this->smtp_conn];
        $selW = null;
        while (is_resource($this->smtp_conn) && !feof($this->smtp_conn)) {
            //Must pass vars in here as params are by reference
            //solution for signals inspired by https://github.com/symfony/symfony/pull/6540
            set_error_handler([$this, 'errorHandler']);
            $n = stream_select($selR, $selW, $selW, $this->Timelimit);
            restore_error_handler();

            if ($n === false) {
                $message = $this->getError()['detail'];

                $this->edebug(
                    'SMTP -> get_lines(): select failed (' . $message . ')',
                    self::DEBUG_LOWLEVEL
                );

                //stream_select returns false when the `select` system call is interrupted
                //by an incoming signal, try the select again
                if (stripos($message, 'interrupted system call') !== false) {
                    $this->edebug(
                        'SMTP -> get_lines(): retrying stream_select',
                        self::DEBUG_LOWLEVEL
                    );
                    $this->setError('');
                    continue;
                }

                break;
            }

            if (!$n) {
                $this->edebug(
                    'SMTP -> get_lines(): select timed-out in (' . $this->Timelimit . ' sec)',
                    self::DEBUG_LOWLEVEL
                );
                break;
            }

            //Deliberate noise suppression - errors are handled afterwards
            $str = @fgets($this->smtp_conn, self::MAX_REPLY_LENGTH);
            $this->edebug('SMTP INBOUND: "' . trim($str) . '"', self::DEBUG_LOWLEVEL);
            $data .= $str;
            //If response is only 3 chars (not valid, but RFC5321 S4.2 says it must be handled),
            //or 4th character is a space or a line break char, we are done reading, break the loop.
            //String array access is a significant micro-optimisation over strlen
            if (!isset($str[3]) || $str[3] === ' ' || $str[3] === "\r" || $str[3] === "\n") {
                break;
            }
            //Timed-out? Log and break
            $info = stream_get_meta_data($this->smtp_conn);
            if ($info['timed_out']) {
                $this->edebug(
                    'SMTP -> get_lines(): stream timed-out (' . $this->Timeout . ' sec)',
                    self::DEBUG_LOWLEVEL
                );
                break;
            }
            //Now check if reads took too long
            if ($endtime && time() > $endtime) {
                $this->edebug(
                    'SMTP -> get_lines(): timelimit reached (' .
                    $this->Timelimit . ' sec)',
                    self::DEBUG_LOWLEVEL
                );
                break;
            }
        }

        return $data;
    }

    /**
     * Enable or disable VERP address generation.
     *
     * @param bool $enabled
     */
    public function setVerp($enabled = false)
    {
        $this->do_verp = $enabled;
    }

    /**
     * Get VERP address generation mode.
     *
     * @return bool
     */
    public function getVerp()
    {
        return $this->do_verp;
    }

    /**
     * Set error messages and codes.
     *
     * @param string $message      The error message
     * @param string $detail       Further detail on the error
     * @param string $smtp_code    An associated SMTP error code
     * @param string $smtp_code_ex Extended SMTP code
     */
    protected function setError($message, $detail = '', $smtp_code = '', $smtp_code_ex = '')
    {
        $this->error = [
            'error' => $message,
            'detail' => $detail,
            'smtp_code' => $smtp_code,
            'smtp_code_ex' => $smtp_code_ex,
        ];
    }

    /**
     * Set debug output method.
     *
     * @param string|callable $method The name of the mechanism to use for debugging output, or a callable to handle it
     */
    public function setDebugOutput($method = 'echo')
    {
        $this->Debugoutput = $method;
    }

    /**
     * Get debug output method.
     *
     * @return string
     */
    public function getDebugOutput()
    {
        return $this->Debugoutput;
    }

    /**
     * Set debug output level.
     *
     * @param int $level
     */
    public function setDebugLevel($level = 0)
    {
        $this->do_debug = $level;
    }

    /**
     * Get debug output level.
     *
     * @return int
     */
    public function getDebugLevel()
    {
        return $this->do_debug;
    }

    /**
     * Set SMTP timeout.
     *
     * @param int $timeout The timeout duration in seconds
     */
    public function setTimeout($timeout = 0)
    {
        $this->Timeout = $timeout;
    }

    /**
     * Get SMTP timeout.
     *
     * @return int
     */
    public function getTimeout()
    {
        return $this->Timeout;
    }

    /**
     * Reports an error number and string.
     *
     * @param int    $errno   The error number returned by PHP
     * @param string $errmsg  The error message returned by PHP
     * @param string $errfile The file the error occurred in
     * @param int    $errline The line number the error occurred on
     */
    protected function errorHandler($errno, $errmsg, $errfile = '', $errline = 0)
    {
        $notice = 'Connection failed.';
        $this->setError(
            $notice,
            $errmsg,
            (string) $errno
        );
        $this->edebug(
            "$notice Error #$errno: $errmsg [$errfile line $errline]",
            self::DEBUG_CONNECTION
        );
    }

    /**
     * Extract and return the ID of the last SMTP transaction based on
     * a list of patterns provided in SMTP::$smtp_transaction_id_patterns.
     * Relies on the host providing the ID in response to a DATA command.
     * If no reply has been received yet, it will return null.
     * If no pattern was matched, it will return false.
     *
     * @return bool|string|null
     */
    protected function recordLastTransactionID()
    {
        $reply = $this->getLastReply();

        if (empty($reply)) {
            $this->last_smtp_transaction_id = null;
        } else {
            $this->last_smtp_transaction_id = false;
            foreach ($this->smtp_transaction_id_patterns as $smtp_transaction_id_pattern) {
                $matches = [];
                if (preg_match($smtp_transaction_id_pattern, $reply, $matches)) {
                    $this->last_smtp_transaction_id = trim($matches[1]);
                    break;
                }
            }
        }

        return $this->last_smtp_transaction_id;
    }

    /**
     * Get the queue/transaction ID of the last SMTP transaction
     * If no reply has been received yet, it will return null.
     * If no pattern was matched, it will return false.
     *
     * @return bool|string|null
     *
     * @see recordLastTransactionID()
     */
    public function getLastTransactionID()
    {
        return $this->last_smtp_transaction_id;
    }
}

Function Calls

None

Variables

None

Stats

MD5 f9f45abea045c96e947441106cc0dced
Eval Count 0
Decode Time 89 ms