stream_socket_client isn't working properly

[analistapr03]

Hi there, I am trying to implement an email validator so I found some code on internet and tried it, but I was getting problems, so debugging I realized that the host I provided is being changed or is supressing some words ("n" in this case) 

Here's an example of the call and its response:

$this->stream = @stream_socket_client('tcp://hotmail-com.olc.protection.outlook.com:25', $errno, $errstr, $timeout);

Response:  Connection refusedhotmail-com.olc.potectio.outlook.com:Coectio efused

I also tried without tcp://

$this->stream = @stream_socket_client('hotmail-com.olc.protection.outlook.com:25', $errno, $errstr, $timeout);

got same response.

 

here's the code I found:

<?php 
/** 
 * Class to validate the email address 
 * 
 * @author CodexWorld.com <contact@codexworld.com> 
 * @copyright Copyright (c) 2018, CodexWorld.com
 * @url https://www.codexworld.com
 */ 
class VerifyEmail { 

    protected $stream = false; 

    /** 
     * SMTP port number 
     * @var int 
     */ 
    protected $port = 25; 
    //protected $port = 587; 

    /** 
     * Email address for request 
     * @var string 
     */ 

// I changed it to another available (isn't the problem)
    protected $from = 'example@localhost.com'; 

    /** 
     * The connection timeout, in seconds. 
     * @var int 
     */ 
    protected $max_connection_timeout = 30; 

    /** 
     * Timeout value on stream, in seconds. 
     * @var int 
     */ 
    protected $stream_timeout = 5; 

    /** 
     * Wait timeout on stream, in seconds. 
     * * 0 - not wait 
     * @var int 
     */ 
    protected $stream_timeout_wait = 0; 

    /** 
     * Whether to throw exceptions for errors. 
     * @type boolean 
     * @access protected 
     */ 
    protected $exceptions = false; 

    /** 
     * The number of errors encountered. 
     * @type integer 
     * @access protected 
     */ 
    protected $error_count = 0; 

    /** 
     * class debug output mode. 
     * @type boolean 
     */ 
    public $Debug = false; 

    /** 
     * 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 
     * * `log` Output to error log as configured in php.ini 
     * @type string 
     */ 
    public $Debugoutput = 'echo'; 

    /** 
     * SMTP RFC standard line ending. 
     */ 
    const CRLF = "rn"; 

    /** 
     * Holds the most recent error message. 
     * @type string 
     */ 
    public $ErrorInfo = ''; 

    /** 
     * Constructor. 
     * @param boolean $exceptions Should we throw external exceptions? 
     */ 
    public function __construct($exceptions = false) { 
        $this->exceptions = (boolean) $exceptions; 
    } 

    /** 
     * Set email address for SMTP request 
     * @param string $email Email address 
     */ 
    public function setEmailFrom($email) { 
        if (!self::validate($email)) { 
            $this->set_error('Invalid address : ' . $email); 
            $this->edebug($this->ErrorInfo); 
            if ($this->exceptions) { 
                throw new verifyEmailException($this->ErrorInfo); 
            } 
        } 
        $this->from = $email; 
    } 

    /** 
     * Set connection timeout, in seconds. 
     * @param int $seconds 
     */ 
    public function setConnectionTimeout($seconds) { 
        if ($seconds > 0) { 
            $this->max_connection_timeout = (int) $seconds; 
        } 
    } 

    /** 
     * Sets the timeout value on stream, expressed in the seconds 
     * @param int $seconds 
     */ 
    public function setStreamTimeout($seconds) { 
        if ($seconds > 0) { 
            $this->stream_timeout = (int) $seconds; 
        } 
    } 

    public function setStreamTimeoutWait($seconds) { 
        if ($seconds >= 0) { 
            $this->stream_timeout_wait = (int) $seconds; 
        } 
    } 

    /** 
     * Validate email address. 
     * @param string $email 
     * @return boolean True if valid. 
     */ 
    public static function validate($email) { 
        return (boolean) filter_var($email, FILTER_VALIDATE_EMAIL); 
    } 

    /** 
     * Get array of MX records for host. Sort by weight information. 
     * @param string $hostname The Internet host name. 
     * @return array Array of the MX records found. 
     */ 
    public function getMXrecords($hostname) {
        //print_r('Hostname: '.$hostname);
        $mxhosts = array(); 
        $mxweights = array(); 
        if (getmxrr($hostname, $mxhosts, $mxweights) === FALSE) { 
            $this->set_error('MX records not found or an error occurred'); 
            $this->edebug($this->ErrorInfo); 
        } else { 
            array_multisort($mxweights, $mxhosts); 
        } 
        /** 
         * Add A-record as last chance (e.g. if no MX record is there). 
         * Thanks Nicht Lieb. 
         * @link http://www.faqs.org/rfcs/rfc2821.html RFC 2821 - Simple Mail Transfer Protocol 
         */ 
        if (empty($mxhosts)) { 
            $mxhosts[] = $hostname; 
        } 
        return $mxhosts; 
    } 

    /** 
     * Parses input string to array(0=>user, 1=>domain) 
     * @param string $email 
     * @param boolean $only_domain 
     * @return string|array 
     * @access private 
     */ 
    public static function parse_email($email, $only_domain = TRUE) { 
        sscanf($email, "%[^@]@%s", $user, $domain); 
        return ($only_domain) ? $domain : array($user, $domain); 
    } 

    /** 
     * Add an error message to the error container. 
     * @access protected 
     * @param string $msg 
     * @return void 
     */ 
    protected function set_error($msg) { 
        $this->error_count++; 
        $this->ErrorInfo = $msg; 
    } 

    /** 
     * Check if an error occurred. 
     * @access public 
     * @return boolean True if an error did occur. 
     */ 
    public function isError() { 
        return ($this->error_count > 0); 
    } 

    /** 
     * Output debugging info 
     * Only generates output if debug output is enabled 
     * @see verifyEmail::$Debugoutput 
     * @see verifyEmail::$Debug 
     * @param string $str 
     */ 
    protected function edebug($str) { 
        if (!$this->Debug) { 
            return; 
        } 
        switch ($this->Debugoutput) { 
            case '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 htmlentities( 
                        preg_replace('/[rn]+/', '', $str), ENT_QUOTES, 'UTF-8' 
                ) 
                . "<br>n"; 
                break; 
            case 'echo': 
            default: 
                //Normalize line breaks 
                $str = preg_replace('/(rn|r|n)/ms', "n", $str); 
                echo gmdate('Y-m-d H:i:s') . "t" . str_replace( 
                        "n", "n t ", trim($str) 
                ) . "n"; 
        } 
    } 

    /** 
     * Validate email
     * @param string $email Email address 
     * @return boolean True if the valid email also exist 
     */ 
    public function check($email) { 
        $result = FALSE; 

        if (!self::validate($email)) { 
            $this->set_error("{$email} incorrect e-mail"); 
            $this->edebug($this->ErrorInfo); 
            if ($this->exceptions) { 
                throw new verifyEmailException($this->ErrorInfo); 
            } 
            return FALSE; 
        } 
        $this->error_count = 0; // Reset errors 
        $this->stream = FALSE; 

        $mxs = $this->getMXrecords(self::parse_email($email));
        //print_r($mxs);
        //print_r($email);
        //print_r($this->from);
        $timeout = ceil($this->max_connection_timeout / count($mxs)); 
        foreach ($mxs as $host) { 
            /** 
             * suppress error output from stream socket client... 
             * Thanks Michael. 
             */ 
            //$this->stream = @stream_socket_client('tcp://'.$host.':'.$this->port, $errno, $errstr, $timeout);
            $this->stream = @stream_socket_client('hotmail-com.olc.protection.outlook.com:25', $errno, $errstr, $timeout);
            printf('el host que se está consultando es: '.$host.' la respuesta es: '.$errstr);
            
            if ($this->stream === FALSE) { 
                if ($errno == 0) { 
                    $this->set_error("Problem initializing the socket"); 
                    $this->edebug($this->ErrorInfo); 
                    if ($this->exceptions) { 
                        throw new verifyEmailException($this->ErrorInfo); 
                    } 
                    return FALSE; 
                } else { 
                    $this->edebug($host . ":" . $errstr); 
                } 
            } else { 
                stream_set_timeout($this->stream, $this->stream_timeout); 
                stream_set_blocking($this->stream, 1); 

                if ($this->_streamCode($this->_streamResponse()) == '220') { 
                    $this->edebug("Connection success {$host}"); 
                    break; 
                } else { 
                    fclose($this->stream); 
                    $this->stream = FALSE; 
                } 
            } 
        } 

        if ($this->stream === FALSE) { 
            $this->set_error("All connection fails"); 
            $this->edebug($this->ErrorInfo); 
            if ($this->exceptions) { 
                throw new verifyEmailException($this->ErrorInfo); 
            } 
            return FALSE; 
        } 

        $this->_streamQuery("HELO " . self::parse_email($this->from)); 
        $this->_streamResponse(); 
        $this->_streamQuery("MAIL FROM: <{$this->from}>"); 
        $this->_streamResponse(); 
        $this->_streamQuery("RCPT TO: <{$email}>"); 
        $code = $this->_streamCode($this->_streamResponse()); 
        $this->_streamResponse(); 
        $this->_streamQuery("RSET"); 
        $this->_streamResponse();
        $code2 = $this->_streamCode($this->_streamResponse()); 
        $this->_streamQuery("QUIT"); 
        fclose($this->stream); 

        $code = !empty($code2)?$code2:$code;
        switch ($code) { 
            case '250': 
            /** 
             * http://www.ietf.org/rfc/rfc0821.txt 
             * 250 Requested mail action okay, completed 
             * email address was accepted 
             */ 
            case '450': 
            case '451': 
            case '452': 
                /** 
                 * http://www.ietf.org/rfc/rfc0821.txt 
                 * 450 Requested action not taken: the remote mail server 
                 * does not want to accept mail from your server for 
                 * some reason (IP address, blacklisting, etc..) 
                 * Thanks Nicht Lieb. 
                 * 451 Requested action aborted: local error in processing 
                 * 452 Requested action not taken: insufficient system storage 
                 * email address was greylisted (or some temporary error occured on the MTA) 
                 * i believe that e-mail exists 
                 */ 
                return TRUE;
            case '550':
                return FALSE; 
            default : 
                return FALSE; 
        } 
    } 

    /** 
     * writes the contents of string to the file stream pointed to by handle 
     * If an error occurs, returns FALSE. 
     * @access protected 
     * @param string $string The string that is to be written 
     * @return string Returns a result code, as an integer. 
     */ 
    protected function _streamQuery($query) { 
        $this->edebug($query); 
        return stream_socket_sendto($this->stream, $query . self::CRLF); 
    } 

    /** 
     * Reads all the line long the answer and analyze it. 
     * If an error occurs, returns FALSE 
     * @access protected 
     * @return string Response 
     */ 
    protected function _streamResponse($timed = 0) { 
        $reply = stream_get_line($this->stream, 1); 
        $status = stream_get_meta_data($this->stream); 

        if (!empty($status['timed_out'])) { 
            $this->edebug("Timed out while waiting for data! (timeout {$this->stream_timeout} seconds)"); 
        } 

        if ($reply === FALSE && $status['timed_out'] && $timed < $this->stream_timeout_wait) { 
            return $this->_streamResponse($timed + $this->stream_timeout); 
        } 


        if ($reply !== FALSE && $status['unread_bytes'] > 0) { 
            $reply .= stream_get_line($this->stream, $status['unread_bytes'], self::CRLF); 
        } 
        $this->edebug($reply); 
        return $reply; 
    } 

    /** 
     * Get Response code from Response 
     * @param string $str 
     * @return string 
     */ 
    protected function _streamCode($str) { 
        preg_match('/^(?<code>[0-9]{3})(s|-)(.*)$/ims', $str, $matches); 
        $code = isset($matches['code']) ? $matches['code'] : false; 
        return $code; 
    } 

} 

/** 
 * verifyEmail exception handler 
 */ 
class verifyEmailException extends Exception { 

    /** 
     * Prettify error message output 
     * @return string 
     */ 
    public function errorMessage() {
        $errorMsg = $this->getMessage(); 
        return $errorMsg; 
    } 

} 

?>

 

Edited August 11, 2021 by requinix
please use the Code <> button when posting code

[requinix]

There's a slight problem here: many mail servers will not let you use RCPT TO to verify the existence of an email address. They'll always succeed, which is absolutely useless for verification.

There are two things you can do to verify an email address: the general syntax of the address itself, and that the domain name exists with an A/AAAA, CNAME/DNAME, or MX DNS record. Look for a library that will do those for you.