Attachments are not recognized even though base64 is sent in the header

Question

I had a problem with sending attachments in php mail. The problem is that the letter appears to be sent and received, but is not recognized as an attachment. If I go to the mail source, I see that it sends base64 and includes the name of the attachment, as it should be, so I am confused why it will not be recognized by the client. Any ideas?

$uid = md5(uniqid(time()));
$headers = "From: ".$from_name." <".$mailto.">\n";
$headers .= "Reply-To: ".$from_mail."\n";
$headers .= "MIME-Version: 1.0\n";
$headers .= "Content-Type: multipart/mixed; boundary=\"".$uid."\"\n";
$headers .= "This is a multi-part message in MIME format.\n";
$headers .= "--".$uid."\n";
$headers .= "Content-type:text/plain\n";
$headers .= "Content-Transfer-Encoding: 8bit\n";
$headers .= $message."\n";

foreach ($_FILES as $file) {
    $name = $file['name'];
    $handle = fopen($file['tmp_name'], "r");
    $content = fread($handle, $file['size']);
    fclose($handle);
    $content = chunk_split(base64_encode($content));

    $headers .= "--{$uid}\n";
    $headers .= "Content-Type: {$file['type']}; name=\"{$name}\"\n";
    $headers .= "Content-Transfer-Encoding: base64\n";
    $headers .= "Content-Disposition: attachment; filename=\"{$name}\"\n";
    $headers .= $content;
}

$headers .= "--{$uid}--";
$mailto = '[e-mail]';
return mail($mailto, $subject, $message, $headers, '-f' . $mailto);

Answer 1

Problem

There are several errors in the code:

• The email header must be completed CRLF. You only have LF.
• A B64 encoded file and message are added to the headers. They should be sent as the body of the message.
• CRLF.
• , CRLF.

, RFC 2046. CRLF. ( BNF, .)

multipart-body := [preamble CRLF]
                  dash-boundary CRLF
                  body-part *encapsulation
                  close-delimiter
                  [CRLF epilogue]

dash-boundary := "--" boundary

body-part := MIME-part-headers [CRLF *OCTET]

encapsulation := delimiter
                 CRLF body-part

delimiter := CRLF dash-boundary

close-delimiter := delimiter "--"

:

$uid = md5(uniqid(time()));
$headers = "From: ".$from_name." <".$mailto.">\r\n";
$headers .= "Reply-To: ".$from_mail."\r\n";
$headers .= "MIME-Version: 1.0\r\n";
$headers .= "Content-Type: multipart/mixed; boundary=\"".$uid."\"\r\n";

$body = "This is a multi-part message in MIME format.\n";
$body .= "--".$uid."\r\n";
$body .= "Content-type:text/plain\r\n";
$body .= "Content-Transfer-Encoding: 8bit\r\n";
$body .= "\r\n";
$body .= $message;

foreach ($_FILES as $file) {
  $name = $file['name'];
  $handle = fopen($file['tmp_name'], "r");
  $content = fread($handle, $file['size']);
  fclose($handle);
  $content = chunk_split(base64_encode($content));

  $body .= "\r\n--{$uid}\r\n";
  $body .= "Content-Type: {$file['type']}; name=\"{$name}\"\r\n";
  $body .= "Content-Transfer-Encoding: base64\r\n";
  $body .= "Content-Disposition: attachment; filename=\"{$name}\"\r\n";
  $body .= "\r\n";
  $body .= $content;
}

$body .= "\r\n--{$uid}--";
$mailto = '[e-mail]';
return mail($mailto, $subject, $body, $headers, '-f' . $mailto);

• - RFC 5322
• RFC 2045 (MIME) : -
• RFC 2046 (MIME) :