php smtp function to send email

The SMTP email sending function implemented in PHP has SMTP verification function and detailed comments. It is suitable for reference by friends who study SMTP email sending.

The complete code is as follows.

<?php
/**
 * smtp发送邮件
 * site bbs.it-home.org
*/
function send_mail($to, $subject = 'No subject', $body) {
    $loc_host = "mail.server";      //发信计算机名，可随意
    $smtp_acc = "test123@163.com"; //Smtp认证的用户名
    $smtp_pass="pwdpwd";          //Smtp认证的密码，一般等同pop3密码
    $smtp_host="smtp.163.com";    //SMTP服务器地址，类似 smtp.tom.com
    $from="test123@163.com";       //发信人Email地址，你的发信信箱地址
    $deliver=$smtp_acc; //回复到指定邮箱
    $headers = "Content-Type: text/plain; charset=\"gb2312\"\r\nContent-Transfer-Encoding: base64";
    $lb="\r\n";                    //linebreak    
    $hdr = explode($lb,$headers);     //解析后的hdr
    if($body) {$bdy = preg_replace("/^\./","..",explode($lb,$body));}//解析后的Body

        $smtp = array(
      //1、EHLO，期待返回220或者250
      array("EHLO ".$loc_host.$lb,"220,250","HELO error: "),
      //2、发送Auth Login，期待返回334
      array("AUTH LOGIN".$lb,"334","AUTH error:"),
      //3、发送经过Base64编码的用户名，期待返回334
      array(base64_encode($smtp_acc).$lb,"334","AUTHENTIFICATION error : "),
      //4、发送经过Base64编码的密码，期待返回235
      array(base64_encode($smtp_pass).$lb,"235","AUTHENTIFICATION error : "));
      //5、发送Mail From，期待返回250
      $smtp[] = array("MAIL FROM: <".$from.">".$lb,"250","MAIL FROM error: ");
      //6、发送Rcpt To。期待返回250
      $smtp[] = array("RCPT TO: <".$to.">".$lb,"250","RCPT TO error: ");
      //7、发送DATA，期待返回354
      $smtp[] = array("DATA".$lb,"354","DATA error: ");
      //8.0、发送From
      $smtp[] = array("From: ".$deliver.$lb,"","");
      //8.2、发送To
      $smtp[] = array("To: ".$to.$lb,"","");
      //8.1、发送标题
      $smtp[] = array("Subject: ".$subject.$lb,"","");
      //8.3、发送其他Header内容
      foreach($hdr as $h) {$smtp[] = array($h.$lb,"","");}
      //8.4、发送一个空行，结束Header发送
      $smtp[] = array($lb,"","");
      //8.5、发送信件主体
      if($bdy) {foreach($bdy as $b) {$smtp[] = array(base64_encode($b.$lb).$lb,"","");}}
      //9、发送“.”表示信件结束，期待返回250
      $smtp[] = array(".".$lb,"250","DATA(end)error: ");
      //10、发送Quit，退出，期待返回221
      $smtp[] = array("QUIT".$lb,"221","QUIT error: ");

        //打开smtp服务器端口
        $fp = @fsockopen($smtp_host, 25);
        if (!$fp) echo "<b>Error:</b> Cannot conect to ".$smtp_host."<br>";
        while($result = @fgets($fp, 1024)){if(substr($result,3,1) == " ") { break; }}
       
        $result_str="";
        //发送smtp数组中的命令/数据
        foreach($smtp as $req){
                //发送信息
                @fputs($fp, $req[0]);
                //如果需要接收服务器返回信息，则
                if($req[1]){
                        //接收信息
                        while($result = @fgets($fp, 1024)){
                                if(substr($result,3,1) == " ") { break; }
                        };
                        if (!strstr($req[1],substr($result,0,3))){
                                $result_str.=$req[2].$result."<br>";
                        }
                }
        }
        //关闭连接
        @fclose($fp);
        return $result_str;
}

//调用示例
#echo send_mail($_POST["email"],$tosubject,$_POST["errortext"]);
echo send_mail('mail_001@126.com','脚本学堂，欢迎大家的光临','程序员之家_bbs.it-home.org');
echo time();
?>