带附件的邮件发送

<?php 
//获得表单信息
$from = $_POST['from'];
$to = $_POST['to']; 
$subject = $_POST['subject']; 
$body = $_POST['body']; 
// 定义分界线 
$boundary = "345894369383"; 			//分界线是一串无规律的字符
//设置header
$header = "Content-type: multipart/mixed; boundary= $boundary/r/n"; 
$header .= "From:$from/r/n"; 
//获得上传文件的文件内容
$file = $_FILES['upload_file']['tmp_name']; 
//确定上传文件的MIME类型 
$mimeType = $_FILES['upload_file']['type']; 
//获得上传文件的文件名 
$fileName = $_FILES['upload_file']['name']; 
//读取上传文件 
$fp = fopen($file, "r"); 					//打开文件
$read = fread($fp, filesize($file)); 		//读入文件
$read = base64_encode($read); 				//base64编码 
$read = chunk_split($read); 				//切割字符串
//建立邮件的主体，分为邮件内容和附件内容两部分
$body = "--$boundary 
Content-type: text/plain; charset=iso-8859-1 
Content-transfer-encoding: 8bit 
$body 
--$boundary 
Content-type: $mimeType; name=$fileName 
Content-disposition: attachment; filename=$fileName 
Content-transfer-encoding: base64 
$read 
--$boundary--"; 
//发送邮件 并输出是否发送成功的信息
if(mail($to, $subject,$body,$header)) 
{
	echo "信件发送成功"; 
}
else 
{
	echo "信件发送失败"; 
}
?>