sm.php

class smtp
{
/* Public Variables */
var $smtp_port;
var $time_out;
var $host_name;
var $log_file;
var $relay_host;
var $debug;
var $auth;
var $user;
var $pass;

/* PRivate Variables */
var $sock;

/* Constractor */
function smtp($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 */
function sendmail($to, $from, $subject = "", $body = "", $mailtype, $cc = "", $bcc = "", $additional_headers = "")
{
$mail_from = $this->get_address($this->strip_comment($from));
$body = ereg_replace("(^|(rn))(\.)", "\1.\3", $body);
$header .= "MIME-Version:1.0rn";
if($mailtype=="HTML"){
$header .= "Content-Type:text/htmlrn";
}
$header .= "To: ".$to."rn";
if ($cc != "") {
$header .= "Cc: ".$cc."rn";
}
$header .= "From: $from<".$from.">;rn";
$header .= "Subject: ".$subject."rn";
$header .= $additional_headers;
$header .= "Date: ".date("r")."rn";
$header .= "X-Mailer:By Redhat (PHP/".phpversion().")rn";
list($msec, $sec) = explode(" ", microtime());
$header .= "Message-ID: <".date("YmdHis", $sec).".".($msec*1000000).".".$mail_from.">;rn";
$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 hostn");
}
return $sent;
}

/* Private Functions */

function smtp_send($helo, $from, $to, $header, $body = "")
{
if (!$this->smtp_putcmd("HELO", $helo)) {
return $this->smtp_error("sending HELO command");
}
#auth
if($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;
}

function smtp_sockopen($address)
{
if ($this->relay_host == "") {
return $this->smtp_sockopen_mx($address);
} else {
return $this->smtp_sockopen_relay();
}
}

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;
}

function smtp_sockopen_mx($address)
{
$domain = ereg_replace("^.+@([^@]+)$", "\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;
}

function smtp_message($header, $body)
{
fputs($this->sock, $header."rn".$body);
$this->smtp_debug(">; ".str_replace("rn", "n".">; ", $header."n>; ".$body."n>; "));

return TRUE;
}

function smtp_eom()
{
fputs($this->sock, "rn.rn");
$this->smtp_debug(". [EOM]n");

return $this->smtp_ok();
}

function smtp_ok()
{
$response = str_replace("rn", "", fgets($this->sock, 512));
$this->smtp_debug($response."n");

if (!ereg("^[23]", $response)) {
fputs($this->sock, "QUITrn");
fgets($this->sock, 512);
$this->log_write("Error: Remote host returned "".$response.""n");
return FALSE;
}
return TRUE;
}

function smtp_putcmd($cmd, $arg = "")
{
if ($arg != "") {
if($cmd=="") $cmd = $arg;
else $cmd = $cmd." ".$arg;
}

fputs($this->sock, $cmd."rn");
$this->smtp_debug(">; ".$cmd."n");

return $this->smtp_ok();
}

function smtp_error($string)
{
$this->log_write("Error: Error occurred while ".$string.".n");
return FALSE;
}

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 (log_file">!@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;
}

function strip_comment($address)
{
$comment = "\([^()]*\)";
while (ereg($comment, $address)) {
$address = ereg_replace($comment, "", $address);
}

return $address;
}

function get_address($address)
{
$address = ereg_replace("([ trn])+", "", $address);
$address = ereg_replace("^.*<(.+)>;.*$", "\1", $address);

return $address;
}

function smtp_debug($message)
{
if ($this->debug) {
echo $message;
}
}
}
?>

mail.php

require("sm.php");
########################################
$smtpserver = "mail.asdf.com";//SMTP server
$smtpserverport =25;//SMTP server port
$smtpusermail = "asdf@asdf.com";//The user's email address of the SMTP server
$smtpemailto = "asdf@QQ.com";//Who to send to
$smtpuser = "asdf@asdf.com"; //SMTP server user account
$smtppass = "asdf";//User password of SMTP server
$mailsubject = "Test Subject";//Mail subject
$mailbody = "

;This is a test mail

;";//Mail content
$mailtype = "HTML";//Email format (HTML/TXT), TXT is text email
########################################
$smtp = new smtp($smtpserver,$smtpserverport,true,$smtpuser,$smtppass);//A true here means that authentication is used, otherwise authentication is not used.
$smtp->debug = TRUE;//Whether to display the sent debugging information
$smtp->sendmail($smtpemailto, $smtpusermail, $mailsubject, $mailbody, $mailtype);

The above introduces the simple class of sending emails in PHP, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.