在开发站群软件时，用到了根据访问域名判断子站点的相关问题。
PHP获取当前域名有两个变量 HTTP_HOST 和 SERVER_NAME，想知道两者的区别以及哪个更加可靠。
本人经过亲自验证 + 查阅官方文档 + 官方BUG列表 + 官方邮件列表 + sitepoint + webmasterworld + google的总结：
相同点：
当满足以下三个条件时，两者会输出相同信息。
1. 服务器为80端口
2. apache的conf中ServerName设置正确
3. HTTP/1.1协议规范
不同点：
1. 通常情况：
_SERVER["HTTP_HOST"] 在HTTP/1.1协议规范下，会根据客户端的HTTP请求输出信息。
_SERVER["SERVER_NAME"] 默认情况下直接输出apache的配置文件httpd.conf中的ServerName值。
2. 当服务器为非80端口时：
_SERVER["HTTP_HOST"] 会输出端口号，例如：mimiz.cn:8080
_SERVER["SERVER_NAME"] 会直接输出ServerName值
因此在这种情况下，可以理解为：HTTP_HOST = SERVER_NAME : SERVER_PORT
3. 当配置文件httpd.conf中的ServerName与HTTP/1.0请求的域名不一致时：
httpd.conf配置如下：
ServerName mimiz.cn
ServerAlias www.mimiz.cn
</virtualhost>
客户端访问域名www.mimiz.cn
_SERVER["HTTP_HOST"] 输出 www.mimiz.cn
_SERVER["SERVER_NAME"] 输出 mimiz.cn
因此，在实际程序中，应尽量使用_SERVER["HTTP_HOST"] 。
问题：处理一个文本文件，发现内容有一个’ ‘（看上去是全角空格），然后用iconv('gbk', 'utf-8',$str)转换格式，只能得到这个空格之前的内容，之后的内容会丢失。
解决方法：首先ord找出这个字符的值（163和117），再用str_replace()(chr(163). chr(117), ' ', $str)将这个特殊符号转为空格，就能解决问题。
php发送邮件(mail)的类
<?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("(^|(\r\n))(\\.)", "\\1.\\3", $body);
$header .= "MIME-Version:1.0\r\n";
if($mailtype=="HTML"){
$header .= "Content-Type:text/html\r\n";
}
$header .= "To: ".$to."\r\n";
if ($cc != "") {
$header .= "Cc: ".$cc."\r\n";
}
$header .= "From: $from<".$from.">;\r\n";
$header .= "Subject: ".$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 $sent;
}
/* Private Functions */
function smtp_send($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 $this->smtp_error("sending <CR>;<LF>;.<CR>;<LF>; [EOM]");
}
if (!$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, $header."\r\n".$body);
$this->smtp_debug(">; ".str_replace()("\r\n", "\n".">; ", $header."\n>; ".$body."\n>; "));
return TRUE;
}
function smtp_eom()
{
fputs($this->sock, "\r\n.\r\n");
$this->smtp_debug(". [EOM]\n");
return $this->smtp_ok();
}
function smtp_ok()
{
$response = str_replace("\r\n", "", fgets($this->sock, 512));
$this->smtp_debug($response."\n");
if (!ereg("^[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;
}
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 $this->smtp_ok();
}
function smtp_error($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 (!@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("([ \t\r\n])+", "", $address);
$address = ereg_replace("^.*<(.+)>;.*$", "\\1", $address);
return $address;
}
function smtp_debug($message)
{
if ($this->debug) {
echo $message;
}
}
}
function sendmail($smtpserver,$smtpuser,$smtppass,$smtpemailto,$smtpusermail, $mailsubject, $mailbody){
$smtp = new smtp($smtpserver,25,true,$smtpuser,$smtppass);
//$smtp->debug = TRUE;
$smtp->sendmail($smtpemailto, $smtpusermail, $mailsubject, $mailbody, "HTML");
}
//such as
//sendmail("smtp.126.com","test@126.com","password","1034555083@qq.com","test@126.com","title","body");
?>