I'm sending a multipart HTML email using PHP's mail() function. In my Postfix configuration I have my SMTP server set to Amazon's SES. Here is the PHP for sending the email:
$boundary = uniqid("HTMLDEMO");
$headers = "From: me@mydomain.com
";
$headers .= "MIME-Version: 1.0
";
$headers .= "Content-Type: multipart/alternative; boundary = ".$boundary."
";
// plain text
$content = "--".$boundary."
" .
"Content-Type: text/plain; charset=ISO-8859-1
" .
"Content-Transfer-Encoding: base64
" .
chunk_split(base64_encode($plaintext_message));
// HTML
$content .= "--".$boundary."
" .
"Content-Type: text/html; charset=ISO-8859-1
" .
"Content-Transfer-Encoding: text/html
" .
"<html><body>".$html_message."</body></html>";
//send message
mail($to, $subject, $content, $headers);
When I echo the message content, this is what I see in the browser:
--HTMLDEMO527d8d851e72f
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: base64
VGhpcyBpcyB0aGUgcGxhaW4gdGV4dCB2ZXJzaW9uIQ==
--HTMLDEMO527d8d851e72f
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: text/html
<html><body><p>My message here.</p></body></html>
But when I view the message source in Gmail, I now see this (including the message headers):
From: me@mydomain.com
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary = HTMLDEMO527d8d851e72f
Message-ID: <blah-blah-blah@email.amazonses.com>
Date: Sat, 9 Nov 2013 01:19:02 +0000
X-SES-Outgoing: 2013.11.09-12.34.5.67
--HTMLDEMO527d8d851e72f
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: base64
VGhpcyBpcyB0aGUgcGxhaW4gdGV4dCB2ZXJzaW9uIQ==
--HTMLDEMO527d8d851e72f
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: text/html
The multipart headers are now double-spaced, causing the HTML to display as plain text. SES is clearly modifying the message headers (it added Message-ID, Date, and X-SES-Outgoing), so could that also be the culprit for the extra spaces in the multipart headers? When I send an identical email from a non-Amazon server, it comes through normally and renders the HTML like it should.
Also, when I send it as a simple HTML email (not multipart), then it works just fine.
Thanks.
