<?php
          
// 通过socket实现SMTP协议的功能
// version: 1.1
// author : DCC
// create : 2014-01-17 23:38:24
// modify : 2014-01-18 16:59:04
// more   : http://www.thinkful.cn/archives/389.html
          
class Dmail_smtp{
              
    var $socket;
    var $host;
    var $user;
    var $pwd;
    var $port;
    var $nickname;
    var $weburl;
              
    // 初始化
    function__construct($host, $user, $pwd, $port=25, $webname='大超超在思考', $weburl="www.thinkful.cn"){
        $this->socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
        $this->host = $host;
        $this->user = $user;
        $this->pwd  = $pwd;
        $this->port = $port;
        $this->nickname = $webname;
        $this->weburl = $weburl;
    }
              
    // 发邮件
    function smtp($to, $from, $subject, $body){
        $conn = socket_connect($this->socket, $this->host, $this->port);
        if( $conn ){
            // 接收连接成功的消息
            $msg  = "succeed connect to ".$this->host.":".$this->port."\n";
            $msg .= $this->_r();
            // 开始认证过程
            $this->_w("HELO ".$this->weburl."\r\n");
            $msg .= $this->_r();
            $this->_w("AUTH LOGIN ".base64_encode($this->user)."\r\n");
            $msg .= $this->_r();
            $this->_w(base64_encode($this->pwd)."\r\n");
            $msg .= $this->_r();
                      
            // 认证成功
            if( stripos($msg, '235 Authentication successful')!==FALSE ){
                $this->_w("MAIL FROM:<{$from}>\r\n");
                $msg .= $this->_r();
                          
                $this->_w("RCPT TO:<{$to}>\r\n");
                $msg .= $this->_r();
                          
                $this->_w("DATA\r\n");
                $msg .= $this->_r();
                          
                // 发送头和正文
                $data = $this->_genHeader($to, $from, $subject)
                    ."\r\n".$this->_genBody($body);
                $this->_w($data);
                          
                $this->_w("\r\n.\r\n");
                $msg .= $this->_r();
                          
                $this->_w("QUIT\r\n");
                $msg .= $this->_r();
            }
        }
        return $msg;
    }
              
    // 生成头部
    private function _genHeader($to, $from, $subject){
        $header  = "MIME-Version:1.0\r\n";
        $header .= "Content-Type: text/plain; charset=\"utf-8\"\r\n";
        $header .= "Subject: =?utf-8?B?".base64_encode($subject)."?=\r\n";
        $header .= "From: ".$this->nickname." <".$from.">\r\n";
        $header .= "To: ".$to."\r\n";
        $header .= "Date: ".date("r")."\r\n";
        list($msec, $sec) = explode(" ", microtime());
        $header .= "Message-ID: <DCC_".date("YmdHis").".".($msec*1000000).".".$from.">\r\n";
        return $header;
    }
              
    // 生成正文
    private function _genBody($body){
        $body = preg_replace("/(^|(\r\n))(\.)/", "\1.\3", $body);
        return $body;
    }
              
    // @发送控制流
    // var: 控制代码
    private function _w($s){
        socket_write($this->socket, $s);
    }
    // @读取返回的数据
    private function _r(){
        return socket_read($this->socket, 1024);
    }
}

<?php
         
// 通过socket实现pop3协议的功能
// version: 1.2
// author : DCC
// create : 2014-01-18 11:26:53
// modify : 2014-01-18 22:57:26
// more   : http://www.thinkful.cn/archives/389.html
         
class Dmail_pop3{
             
    var $socket;
    var $host;
    var $user;
    var $pwd;
    var $port;
    var $content;
             
    // 初始化
    function __construct($host, $user, $pwd, $port=110){
        $this->socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
        $this->host = $host;
        $this->user = $user;
        $this->pwd  = $pwd;
        $this->port = $port;
    }
             
    // 收邮件
    function pop3(){
        $conn = socket_connect($this->socket, $this->host, $this->port);
        if( $conn ){
            // 接收连接成功的消息
            $msg  = "DCC: succeed connect to ".$this->host.":".$this->port."\n";
            $msg .= $this->_r();
            // 开始认证过程
            $this->_w("USER ".$this->user."\r\n");
            $msg .= $this->_r();
            $this->_w("PASS ".$this->pwd."\r\n");
            $msg .= $this->_r();
                     
            // 认证成功
            if( substr_count($msg, '+OK')>=3 ){
                //向服务器发送请求邮箱信息
                $this->_w("STAT\r\n");
                $mail_info = $this->_r();
                $msg .= $mail_info;
                preg_match('/\+OK\s(\d+)\s(\d+)/', $mail_info, $m);
                $mail_num = $m[1];
                $mail_len = $m[2];
                         
                //向服务器发送邮件i信息的请求
                $this->content = '';
                for( $i=1; $i<=$mail_num; $i++ ){
                    // 查看该邮件的信息
                    $this->_w("LIST {$i}\r\n");
                    usleep(160000);// waiting 0.16s
                    $mail_info = $this->_r();
                    $msg .= $mail_info;
                    preg_match('/\+OK\s(\d+)\s(\d+)/', $mail_info, $m);
                    //接收服务器返回的信息
                    $this->_w("RETR {$i}\r\n");
                    $msg.= 'DCC: reading mail(id='.$m[1].')\'s content(length='.$m[2].'byte):'."\n";
                    $data = '';
                    while( strlen($data)<$m[2] ){
                        $msg .= '. ';
                        $data .= socket_read($this->socket, 4096);
                    }
                    $this->content .= $data;
                    $msg.= "\nDCC: mail(id=".$m[1].')\'s content(length='.$m[2].'byte) read complete.'."\n";
                }
                         
            }
        }
        return $msg;
    }
             
    // 返回收取邮件内容
    function getContent(){
        return $this->content;
    }
             
    // @发送控制流
    // var: 控制代码
    private function _w($s){
        socket_write($this->socket, $s);
    }
    // @读取返回的数据
    // var: 数据长度
    private function _r($len=1024){
        return socket_read($this->socket, $len);
    }
}

// 调用SMTP时
require_once 'dsmtp.cls.php';
$host = "smtp.qq.com";
// 使用QQ邮箱和密码
$user = '*******@qq.com';
$pwd  = '*******';
$dmail = new Dmail_smtp($host, $user, $pwd);
$msg = $dmail->smtp($to, $from, $subject, $body);
       
       
// ********************************
// ********************************
// 调用POP3时（后续处理复杂一点）
require_once 'dpop3.cls.php';
$host = "pop.qq.com";
$dmail = new Dmail_pop3($host, $user, $pwd);
$msg = $dmail->pop3();
$ret = $msg;
        
if( strpos($msg, 'read complete')!==FALSE ){
    $ct = $dmail->getContent();
    $mail_list_arr = explode('X-QQ-SSF: ', $ct);
    array_shift($mail_list_arr);// 去除第一个
    $mail_list_arr = array_reverse($mail_list_arr);
    foreach( $mail_list_arr as $v ){
        // 中文标题的处理
        if( preg_match('/Subject: =\?([^?]+)\?B\?([^?]+)\?=/i', $v, $subject) ){
            $tmp_s = base64_decode($subject[2]);
            $tmp_s = $subject[1]=='gbk'||$subject[1]=='gb2312'? iconv('gbk', 'utf-8', $tmp_s) : $tmp_s;
        }
        // 英文标题
        else if( preg_match('/Subject: (.*?)\r\n/i', $v, $subject) ){
            $tmp_s = $subject[1];
        }
        else{
            $tmp_s = '邮件标题';
        }
        preg_match('/From: [^<]+<(.*?)>/i', $v, $from);
        preg_match('/Date: (.*?)\r\n/i', $v, $date);
                
        $mail_list .= $tmp_s.'|#DCC_LIST_INNER#|'
            .$from[1].'|#DCC_LIST_INNER#|'
            .$date[1].'|#DCC_MAIL_LIST_SEP#|';
    }
    $ret .= '|#DCC_POP3_DATA_SEP#|'.$mail_list;
}
echo $ret;
die();