使用PHP通过SMTP发送电邮

背景

• 需求：遇到一个项目需要服务器发送一封通知邮件给用户。本来以为很难，结果业主方的OA系统邮件是标准的smtp协议。一下子很简单了。服务端使用的PHP开发的，因此搞定PHP的smtp功能即可。
  一轮网上的搜索，发现原生的mail确实麻烦。我尝试配置IIS，效果不理想。找了phpMailer（GitHub）等相关项目，又太过复杂庞大，因为需求简单而时间很紧，就找了过去他人开发的一个通用class使用
• 原作者出处： http://www.daixiaorui.com

方案

• 使用找来的代码，进行一定的改造适配。原本的版本是适配PHP5.0，我这里服务端已经到PHP7.X。
• 维护通用smtp类供应请求使用
• 维护一个响应客户端请求的脚本即可

实战

• 部署到业主服务器之前，先配置个人的163邮箱smtp功能做测试
• 业主提供相关smtp服务器信息之后，一次成功
• 优化余地：业主方也提供pop3协议读取邮件，后续应该可以配套邮件读取的响应处理

".$_POST['content']."";//邮件内容
 * $mailtype = "HTML";//邮件格式（HTML/TXT）,TXT为文本邮件
 * //************************ 配置信息 ****************************
 * $smtp = new smtp($smtpserver,$smtpserverport,true,$smtpuser,$smtppass);//这里面的一个true是表示使用身份验证,否则不使用身份验证.
 * $smtp->debug = true;//是否显示发送的调试信息
 * $state = $smtp->sendmail($smtpemailto, $smtpusermail, $mailtitle, $mailcontent, $mailtype);
 * echo "
";
 * if($state==""){
 *  echo "对不起，邮件发送失败！请检查邮箱填写是否有误。";
 *  echo "点此返回";
 *  exit();
 * }
 * echo "恭喜！邮件发送成功！！";
 * echo "点此返回";
 * echo "
";
 */
class smtp
{

/* Public Variables */

    public $smtp_port;

    public $time_out;

    public $host_name;

    public $log_file;

    public $relay_host;

    public $debug;

    public $auth;

    public $user;

    public $pass;

/* Private Variables */
    public $sock;


/* Constractor */
    public function __construct($relay_host = "", $smtp_port = 25, $auth = false, $user, $pass)
    {

        $this->debug = false;

        $this->smtp_port = $smtp_port;

        $this->relay_host = $relay_host;

        $this->time_out = 30; //is used in fsockopen()

        $this->auth = $auth; //auth

        $this->user = $user;

        $this->pass = $pass;

        $this->host_name = "localhost"; //is used in HELO command
        $this->log_file = "";

        $this->sock = false;

    }

/* Main Function */

    public function sendmail($to, $from, $subject = "", $body = "", $mailtype, $cc = "", $bcc = "", $additional_headers = "")
    {

        $mail_from = $this->get_address($this->strip_comment($from));

        $body = preg_replace("/(^|(\r\n))(\.)/", "\1.\3", $body);

        $header = "MIME-Version:1.0\r\n";

        if ($mailtype == "HTML") {

            $header .= "Content-Type:text/html;charset=utf-8\r\n";

        }

        $header .= "To: " . $to . "\r\n";

        if ($cc != "") {

            $header .= "Cc: " . $cc . "\r\n";

        }

        $header .= "From: $from<" . $from . ">\r\n";

        $subject = mb_convert_encoding($subject, 'gbk', 'utf8');

        $header .= "Subject: " . $subject . "\r\n";

        $header .= $additional_headers;

        $header .= "Date: " . date("r") . "\r\n";

        $header .= "X-Mailer:By Redhat (PHP/" . phpversion() . ")\r\n";

        list($msec, $sec) = explode(" ", microtime());

        $header .= "Message-ID: <" . date("YmdHis", $sec) . "." . ($msec * 1000000) . "." . $mail_from . ">\r\n";

        $TO = explode(",", $this->strip_comment($to));

        if ($cc != "") {

            $TO = array_merge($TO, explode(",", $this->strip_comment($cc)));

        }

        if ($bcc != "") {

            $TO = array_merge($TO, explode(",", $this->strip_comment($bcc)));

        }

        $sent = true;

        foreach ($TO as $rcpt_to) {

            $rcpt_to = $this->get_address($rcpt_to);

            if (!$this->smtp_sockopen($rcpt_to)) {

                $this->log_write("Error: Cannot send email to " . $rcpt_to . "\n");

                $sent = false;

                continue;

            }

            if ($this->smtp_send($this->host_name, $mail_from, $rcpt_to, $header, $body)) {

                $this->log_write("E-mail has been sent to <" . $rcpt_to . ">\n");

            } else {

                $this->log_write("Error: Cannot send email to <" . $rcpt_to . ">\n");

                $sent = false;

            }

            fclose($this->sock);

            $this->log_write("Disconnected from remote host\n");

        }

        return $sent;

    }

/* Private Functions */

    public function smtp_send($helo, $from, $to, $header, $body = "")
    {

        if (!$this->smtp_putcmd("HELO", $helo)) {

            return $this->smtp_error("sending HELO command");

        }

        if ($this->auth) {

            if (!$this->smtp_putcmd("AUTH LOGIN", base64_encode($this->user))) {

                return $this->smtp_error("sending HELO command");

            }

            if (!$this->smtp_putcmd("", base64_encode($this->pass))) {

                return $this->smtp_error("sending HELO command");

            }

        }

        if (!$this->smtp_putcmd("MAIL", "FROM:<" . $from . ">")) {

            return $this->smtp_error("sending MAIL FROM command");

        }

        if (!$this->smtp_putcmd("RCPT", "TO:<" . $to . ">")) {

            return $this->smtp_error("sending RCPT TO command");

        }

        if (!$this->smtp_putcmd("DATA")) {

            return $this->smtp_error("sending DATA command");

        }

        if (!$this->smtp_message($header, $body)) {

            return $this->smtp_error("sending message");

        }

        if (!$this->smtp_eom()) {

            return $this->smtp_error("sending . [EOM]");

        }

        if (!$this->smtp_putcmd("QUIT")) {

            return $this->smtp_error("sending QUIT command");

        }

        return true;

    }

    public function smtp_sockopen($address)
    {

        if ($this->relay_host == "") {

            return $this->smtp_sockopen_mx($address);

        } else {

            return $this->smtp_sockopen_relay();

        }

    }

    public function smtp_sockopen_relay()
    {

        $this->log_write("Trying to " . $this->relay_host . ":" . $this->smtp_port . "\n");

        $this->sock = @fsockopen($this->relay_host, $this->smtp_port, $errno, $errstr, $this->time_out);

        if (!($this->sock && $this->smtp_ok())) {

            $this->log_write("Error: Cannot connenct to relay host " . $this->relay_host . "\n");

            $this->log_write("Error: " . $errstr . " (" . $errno . ")\n");

            return false;

        }

        $this->log_write("Connected to relay host " . $this->relay_host . "\n");

        return true;

    }

    public function smtp_sockopen_mx($address)
    {

        $domain = preg_replace("/^.+@([^@]+)$/i", "$1", $address);

        if (!@getmxrr($domain, $MXHOSTS)) {

            $this->log_write("Error: Cannot resolve MX \"" . $domain . "\"\n");

            return false;

        }

        foreach ($MXHOSTS as $host) {

            $this->log_write("Trying to " . $host . ":" . $this->smtp_port . "\n");

            $this->sock = @fsockopen($host, $this->smtp_port, $errno, $errstr, $this->time_out);

            if (!($this->sock && $this->smtp_ok())) {

                $this->log_write("Warning: Cannot connect to mx host " . $host . "\n");

                $this->log_write("Error: " . $errstr . " (" . $errno . ")\n");

                continue;

            }

            $this->log_write("Connected to mx host " . $host . "\n");

            return true;

        }

        $this->log_write("Error: Cannot connect to any mx hosts (" . implode(", ", $MXHOSTS) . ")\n");

        return false;

    }

    public function smtp_message($header, $body)
    {

        fputs($this->sock, $header . "\r\n" . $body);

        $this->smtp_debug("> " . str_replace("\r\n", "\n" . "> ", $header . "\n> " . $body . "\n> "));

        return true;

    }

    public function smtp_eom()
    {

        fputs($this->sock, "\r\n.\r\n");

        $this->smtp_debug(". [EOM]\n");

        return $this->smtp_ok();

    }

    public function smtp_ok()
    {

        $response = str_replace("\r\n", "", fgets($this->sock, 512));

        $this->smtp_debug($response . "\n");

        if (!preg_match("/^[23]/", $response)) {

            fputs($this->sock, "QUIT\r\n");

            fgets($this->sock, 512);

            $this->log_write("Error: Remote host returned \"" . $response . "\"\n");

            return false;

        }

        return true;

    }

    public function smtp_putcmd($cmd, $arg = "")
    {

        if ($arg != "") {

            if ($cmd == "") {
                $cmd = $arg;
            } else {
                $cmd = $cmd . " " . $arg;
            }

        }

        fputs($this->sock, $cmd . "\r\n");

        $this->smtp_debug("> " . $cmd . "\n");

        return $this->smtp_ok();

    }

    public function smtp_error($string)
    {

        $this->log_write("Error: Error occurred while " . $string . ".\n");

        return false;

    }

    public function log_write($message)
    {

        $this->smtp_debug($message);

        if ($this->log_file == "") {

            return true;

        }

        $message = date("M d H:i:s ") . get_current_user() . "[" . getmypid() . "]: " . $message;

        if (!@file_exists($this->log_file) || !($fp = @fopen($this->log_file, "a"))) {

            $this->smtp_debug("Warning: Cannot open log file \"" . $this->log_file . "\"\n");

            return false;

        }

        flock($fp, LOCK_EX);

        fputs($fp, $message);

        fclose($fp);

        return true;

    }

    public function strip_comment($address)
    {

        $comment = "/\([^()]*\)/";

        while (preg_match($comment, $address)) {

            $address = ereg_replace($comment, "", $address);

        }

        return $address;

    }

    public function get_address($address)
    {

        $address = preg_replace("/([ \t\r\n])+/", "", $address);

        $address = preg_replace("/^.*<(.+)>.*$/", "\1", $address);

        return $address;

    }

    public function smtp_debug($message)
    {

        if ($this->debug) {

            echo $message;

        }

    }

}
?>