simple Mime/Multipart email class for sending attachments and a text or html body in the charset of your choosing

mime.php

<?php

/*
 *  simple Mime/Multipart email class for sending attachments and a text or html body in the charset of your choosing
 *  2011 tom slankard, earthmine inc
 */

class Mime {
  
  private $boundary = null;
  public $to = null;
  public $from = null;
  public $subject = null;
  public $body = null;
  public $type = "text/plain; charset=utf-8";
  public $attachments = Array();
  public $headers = Array();

  public function __construct() {
    $this->boundary = md5(uniqid(time()));
  }

  private function separator() {
    return "--$this->boundary\r\n";
  }

  private function lastSeparator() {
    return "--$this->boundary--";
  }

  private function textHeaders($type) {
    return
      "Content-type: $type\r\n"
      ."Content-Transfer-Encoding: 7bit\r\n\r\n";
  }

  private function attachmentHeaders($filename) {
    return
      "Content-Type: application/octet-stream; name=\"".$filename."\"\r\n"
      ."Content-Transfer-Encoding: base64\r\n"
      ."Content-Disposition: attachment; filename=\"".$filename."\"\r\n\r\n";
  }

  private function constructText($message, $type) {
    $result = $this->separator();
    $result .= $this->textHeaders($type);
    $result .= "$message\r\n\r\n";
    return $result;
  }

  private function constructAttachment($filename) {
    $path = pathinfo($filename);
    $content = chunk_split(base64_encode(file_get_contents($filename)));
    $result = $this->separator();
    $result .= $this->attachmentHeaders($path['basename']);
    $result .= "$content\r\n\r\n";
    return $result;
  }

  private function constructMultipartMessage() {

    $result = "From: $this->from\r\n"
      ."MIME-Version: 1.0\r\n"
      ."Content-Type: multipart/mixed; boundary=\"$this->boundary\"\r\n";

    foreach($this->headers as $header) {
      $result .= "$header\r\n";
    }

    if($this->body != null) {
      $result .= $this->constructText($this->body, $this->type);
    }

    foreach($this->attachments as $attachment) {
      $result .= $this->constructAttachment($attachment);
    }

    $result .= $this->lastSeparator();
    return $result;
  }

  public function send() {
    $message = $this->constructMultipartMessage();
    return mail($this->to, $this->subject, "", $message);
  }

}

/*

usage:

$mime = new Mime();
$mime->subject = "Hello World";
$mime->to = "tom@example.com";
$mime->from = "jerry@example.com";
$mime->body = "See ya later.";
$mime->attachments[] = "foo.png"; //  attach local file named foo.png
$mime->send();

*/

?>