Attachments not recognized despite base64 being sent in header

Question

I'm having a problem with sending attachments in php mail. The problem is that the email appears to send and is received, but isn't recognized as an attachment. If I go into the source of the mail, I can see that it's sending the base64 and includes the attachment name as it should so I'm confused why it wouldn't 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}--";
$mailto = 'myemail@email.com';
return mail($mailto, $subject, $message, $headers, '-f' . $mailto);

you can have a look at this http://stackoverflow.com/questions/11004377/php-sending-emails-with-file-attachments-email-not-sending-at-all — user3470953, Apr 28 '14 at 11:52
Don’t send email using `mail`, use a mailer class like PHPMailer or Swift Mail instead. — CBroe, Apr 28 '14 at 12:12
Try to put a `PHP_EOL` at the begin and end of every boundary. `$headers .= "--{$uid}--" . PHP_EOL;` — TiMESPLiNTER, Apr 30 '14 at 14:08

score 2 · Answer 1 · edited Oct 07 '21 at 05:59

Problem

There are a number of things wrong with your code:

Email headers must be terminated by CRLF. You only have LF.
The B64-encoded file and the message are added to the headers. They should be sent as message body.
There must be an extra CRLF between the message headers and the message body in each part.
The body parts must be separated by delimiters that begin with a CRLF.

Email syntax

This is an excerpt of what the structure of a multi-part message body looks like according to RFC 2046. Pay special attention to the CRLF's. (BNF syntax, somewhat simplified.)


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 "--"

The code

Your code could look something like this:

$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}--";
$mailto = 'myemail@email.example';
return mail($mailto, $subject, $body, $headers, '-f' . $mailto);

Attachments not recognized despite base64 being sent in header

1 Answers1

Problem

Email syntax

The code

References