Drafting IMAP emails with an attachment using PHP

Question

I'm trying to add an attachment to emails that I draft but cannot seem to get it to work. I've tried to follow the examples here and here but without success.

Here's what I'm able to do so far:

1. Connect to the Exchange server
2. Open the mailbox
3. Draft an html email
4. Append the email to the mailbox and have it render the html correctly. (when using text/html as the content-type). Using anything else displays the html as plaintext.

As an additional note, after being drafted, the emails are appended to a mailbox on an Exchange 2010 server and are viewed then sent via Outlook 2010.

Below is my mailer class and the code to draft the email.

mailer.php

<?php

class mailer
{
    const USER      =   'user';
    const PASSWORD  =   'pass';
    const MAILBOX   =   '{conn}DRAFTS';

    // STRING ORDER: $content-type . $from . $to . $cc . $subject . "\r\n\r\n" . $message
    public $message;
    public $imap_conn;
    public $boundary;

    function __construct()
    {
        // Open the message property so we can start appending strings.
        $this->message = '';

        // Open the IMAP connection
        $this->imap_conn = imap_open(self::MAILBOX,self::USER,self::PASSWORD);
    }

    public function content_type($string_type)
    {
        $this->message .= "Content-type:{$string_type}\r\n";
    }

    public function from($string_from)
    {
        $this->message .= "From:{$string_from}\r\n";
    }

    public function to($string_to)
    {
        $this->message .= "To:{$string_to}\r\n";
    }

    public function cc($string_cc)
    {
        $this->message .= "Cc:{$string_cc}\r\n";
    }

    public function mime($float_mime_version)
    {
        $this->message .= "MIME-Version:{$float_mime_version}\r\n";
    }

    public function subject($string_subject)
    {
        $this->message .= "Subject:{$string_subject}\r\n\r\n";
    }

    public function message($string_message)
    {
        $this->message .= "{$string_message}\r\n";
    }

    public function set_boundary($string_boundary)
    {
        $this->boundary = $string_boundary;
    }

    public function append()
    {
        imap_append($this->imap_conn,self::MAILBOX,$this->message,"\\Draft");
        imap_close($this->imap_conn);
    }
}

?>

Draft code

// A random hash used for the boundary
$rh = md5(date('c',time()));
$data = chunk_split(base64_encode('Testing'));


$m = new mailer;
$m->set_boundary('--PHP-mixed-' . $rh);
$m->content_type('multipart/mixed; boundary="' . $m->boundary . '"');
$m->mime('1.0');
$m->from('[email protected]');
$m->to('[email protected]');
$m->cc('[email protected],[email protected]');
$m->subject('A new email');
$m->message("
    {$m->boundary}
    Content-Type: text/html; charset=\"utf-8\"
    Content-Transfer-Encoding: base64

    Testing my <b>HTML</b>
    </br>
    {$m->boundary}
    Content-Type: application/octet-stream; name=\"test.txt\"
    Content-Transfer-Encoding: base64
    Content-Disposition: attachment; filename=\"test.txt\"

    {$data}
    {$m->boundary}--
    "));
$m->append();

The message before its appended

Content-type:multipart/mixed; boundary="--PHP-mixed-b408f941593cf92b5a8bd365abb4e64f"
MIME-Version:1.0
From:[email protected]
To:[email protected]
Cc:[email protected]
Subject:New Message


            --PHP-mixed-b408f941593cf92b5a8bd365abb4e64f
            Content-Type: text/html; charset="utf-8"
            Content-Transfer-Encoding: "base64"

            My <b>html</b> content



            --PHP-mixed-b408f941593cf92b5a8bd365abb4e64f
            Content-Type: application/octet-stream; name="test.txt"
            Content-Transfer-Encoding: base64
            Content-Disposition: attachment; filename="test.txt"



            --PHP-mixed-b408f941593cf92b5a8bd365abb4e64f--

Answer 1

Question: How do I add an attachment to an email drafted with PHP via IMAP?

Answer: In short, the issue was in two places.

1. Improper placement of newlines (\r\n). A single newline should be after each header and two newlines after each ending header of a section. See Figure 1.

2. Improper boundaries. Boundaries should start with -- followed by a unique string. The ending boundary of the message should begin and end with -- See Figure 2

Figure 1

Content-Type: text/html\r\n
Content-Encoding: base64\r\n\r\n
"Message text here."\r\n

Figure 2

--unique
Content-Type: text/html\r\n
Content-Encoding: base64\r\n\r\n
HTML stuff here.\r\n
--unique
Content-Type: application/octet-stream\r\n
Content-Disposition: attachment; filename=\"logs.csv\"\r\n
Content-Transfer-Encoding: base64\r\n\r\n
Attachment(s)\r\n
--unique--

I plan on doing a more in depth write-up on this as it took me a very long time to get it right.