Code for sending emails using SMTP under PHP_PHP Tutorial

A recent project required SMTP to send emails. The previous library class no longer exists, and I don’t like to install pear or use pear’s net/smtp class. It feels too complicated. I extracted the core directly from discuz and modified it slightly.
From the protocol analysis website, we found the commands and responses of the SMTP protocol. The conversation between the SMTP protocol sending SMTP and receiving SMTP is completed by sending SMTP commands and receiving SMTP feedback responses. Commonly used commands are as follows:
HELLO＜domain＞＜CRLF＞A HELLO command that identifies the sender to receive SMTP.
MAIL FROM:＜reverse-path＞＜CRLF＞＜reverse-path＞is the sender address. This command tells the receiver the start of a new mail transmission and initializes all status and buffers. This command begins a mail transfer process that ultimately completes the transfer of mail data to one or more mailboxes.
RCPT TO:＜forward-path＞＜CRLF＞＜forward-path> identifies the address of each email recipient
DATA＜CRLF＞
Receiving SMTP will treat subsequent actions as email data for processing , with . identifying the end of the data.
REST＜CRLF＞Exit/Reset the current mail transmission
NOOP＜CRLF＞requires receiving SMTP only for OK response. (For testing)
QUIT requires the receiving SMTP to return an OK response and close the transmission.
VRFY＜string＞＜CRLF＞Verify whether the specified mailbox exists. Due to security reasons, this command is usually prohibited by the server.
EXPN＜string＞＜CRLF＞Verifies whether the given mailbox list exists, expands the mailbox list, and is often prohibited from use.
HELP＜CRLF＞Query what commands the server supports

Note: means carriage return and line feed, and the ASCII codes are 13 and 10 (decimal) respectively.

In addition, you can use telnet under command to simply use SMTP manually.
For example:


telnet smtp.263.net 25
Trying 211.150.96.25...
Connected to smtp.263.net.
Escape character is '^ ]'.
220 Welcome to coremail System(With Anti-Spam) 2.1 for 263(040326)
HELO weiqiong@cctk.net
250 smtp.263.net
mail from:weiqiong@cctk .net
250 Ok
rcpt to:g2_t1@263.net
250 Ok
data
354 End data with .haha
.
250 Ok: queued as B9E452FF3E
quit
221 Bye
Connection closed by foreign host. Basically, you can write a simple SMTP class.

class stmp{ 

    private $mailcfg=array(); 
    private $error_msg=''; 

    function __construct($mailcfg){ 

        $this->mailcfg=$mailcfg; 

    } 

    public function send($mail){ 
        $mailcfg=$this->mailcfg; 
        if(!$fp = fsockopen($mailcfg['server'], $mailcfg['port'], $errno, $errstr, 30)) { 
            return $this->error("($mailcfg[server]:$mailcfg[port]) CONNECT - Unable to connect to the SMTP server, please check your "mail_config.php"."); 
        } 
         stream_set_blocking($fp, true); 
         $lastmessage = fgets($fp, 512); 
        if(substr($lastmessage, 0, 3) != '220') { 
            return $this->error("$mailcfg[server]:$mailcfg[port] CONNECT - $lastmessage"); 
        } 
        fputs($fp, ($mailcfg['auth'] ? 'EHLO' : 'HELO')." ".$mailcfg['auth_username']."rn"); 
        $lastmessage = fgets($fp, 512); 
        if(substr($lastmessage, 0, 3) != 220 && substr($lastmessage, 0, 3) != 250) { 
            return $this->error("($mailcfg[server]:$mailcfg[port]) HELO/EHLO - $lastmessage"); 
        } 
        while(1) { 
            if(substr($lastmessage, 3, 1) != '-' || empty($lastmessage)) { 
                 break; 
             } 
             $lastmessage = fgets($fp, 512); 
        } 
        if($mailcfg['auth']) { 
            fputs($fp, "AUTH LOGINrn"); 
            $lastmessage = fgets($fp, 512); 
            if(substr($lastmessage, 0, 3) != 334) { 
                return $this->error("($mailcfg[server]:$mailcfg[port]) AUTH LOGIN - $lastmessage"); 
            } 
            fputs($fp, base64_encode($mailcfg['auth_username'])."rn"); 
            $lastmessage = fgets($fp, 512); 
            if(substr($lastmessage, 0, 3) != 334) { 
                return $this->error("($mailcfg[server]:$mailcfg[port]) USERNAME - $lastmessage"); 
            } 

            fputs($fp, base64_encode($mailcfg['auth_password'])."rn"); 
            $lastmessage = fgets($fp, 512); 
            if(substr($lastmessage, 0, 3) != 235) { 
                return $this->error("($mailcfg[server]:$mailcfg[port]) PASSWORD - $lastmessage"); 
            } 

            $email_from = $mailcfg['from']; 
        } 
        fputs($fp, "MAIL FROM: <".preg_replace("/.*<(.+?)>.*/", "\1", $email_from).">rn"); 
        $lastmessage = fgets($fp, 512); 
        if(substr($lastmessage, 0, 3) != 250) { 
            fputs($fp, "MAIL FROM: <".preg_replace("/.*<(.+?)>.*/", "\1", $email_from).">rn"); 
            $lastmessage = fgets($fp, 512); 
            if(substr($lastmessage, 0, 3) != 250) { 
                return $this->error("($mailcfg[server]:$mailcfg[port]) MAIL FROM - $lastmessage"); 
            } 
        } 

        $email_to=$mail['to']; 
        foreach(explode(',', $email_to) as $touser) { 
            $touser = trim($touser); 
            if($touser) { 
                fputs($fp, "RCPT TO: <$touser>rn"); 
                $lastmessage = fgets($fp, 512); 
                if(substr($lastmessage, 0, 3) != 250) { 
                    fputs($fp, "RCPT TO: <$touser>rn"); 
                    $lastmessage = fgets($fp, 512); 
                    return $this->error("($mailcfg[server]:$mailcfg[port]) RCPT TO - $lastmessage"); 
                } 
            } 
        } 
        fputs($fp, "DATArn"); 
        $lastmessage = fgets($fp, 512); 
        if(substr($lastmessage, 0, 3) != 354) { 
            return $this->error("($mailcfg[server]:$mailcfg[port]) DATA - $lastmessage"); 
        } 
        $str="To: $email_tornFrom: $email_fromrnSubject: ".$mail['subject']."rnrn".$mail['content']."rn.rn"; 
        fputs($fp, $str); 
        fputs($fp, "QUITrn"); 
        return true; 
    } 

    public function get_error(){ 
        return $this->error_msg; 
    } 

    private function error($msg){ 
        $this->error_msg.=$msg; 
        return false; 
    } 

} 
?> 

    简单的调用例子：

$mailcfg['server'] = 'smtp.163.com'; 

        $mailcfg['port'] = '25'; 

        $mailcfg['auth'] = 1; 
        $mailcfg['from'] = 'test '; 

        $mailcfg['auth_username'] = 'test'; 

        $mailcfg['auth_password'] = 'password';     
        $stmp=new stmp($mailcfg); 
        $mail=array('to'=>'test@gmail.com','subject'=>'测试标题','content'=>'邮件内容PHP面向对象'); 
        if(!$stmp->send($mail)){ 
            echo $stmp->get_error(); 
        }else{ 
            echo 'mail succ!'; 
        } 
?> 

  如果发送成功，你就可以去邮箱查看邮件了。^_^