[SOLVED] Simple PHP form: Attachment to email (code golf)

Simple PHP form: Attachment to email (code golf)

Imagine a user that would like to put a form on their website that would allow a website visitor to upload a file and a simple message, which will immediately be emailed (ie, the file is not stored on the server, or if it is then only temporarily) as a file attachment with the note in the message body.

See more details at http://a2zsollution.com/php-secure-e-mail/

What is the simplest way to accomplish this?

Simplest in terms of:

Size (code golf)
Ease of implementation (ideally all in one file, needs few to no external resources)
Not obfuscated for the sake of obfuscation (tradeoffs for size are fine)
Self contained example (if called without a form post, it displays the form)

This is nearly the reverse of: How to get email and their attachments from PHP. It almost could have been answered in Compiling email with multiple attachments in PHP, but it doesn't actually show code.

Solution

Just for fun I thought I'd knock it up. It ended up being trickier than I thought because I went in not fully understanding how the boundary part works, eventually I worked out that the starting and ending '--' were significant and off it went.

<?php
    if(isset($_POST['submit']))
    {
        //The form has been submitted, prep a nice thank you message
        $output = '<h1>Thanks for your file and message!</h1>';
        //Set the form flag to no display (cheap way!)
        $flags = 'style="display:none;"';

        //Deal with the email
        $to = 'me@example.com';
        $subject = 'a file for you';

        $message = strip_tags($_POST['message']);
        $attachment = chunk_split(base64_encode(file_get_contents($_FILES['file']['tmp_name'])));
        $filename = $_FILES['file']['name'];

        $boundary =md5(date('r', time())); 

        $headers = "From: webmaster@example.com\r\nReply-To: webmaster@example.com";
        $headers .= "\r\nMIME-Version: 1.0\r\nContent-Type: multipart/mixed; boundary=\"_1_$boundary\"";

        $message="This is a multi-part message in MIME format.

--_1_$boundary
Content-Type: multipart/alternative; boundary=\"_2_$boundary\"

--_2_$boundary
Content-Type: text/plain; charset=\"iso-8859-1\"
Content-Transfer-Encoding: 7bit

$message

--_2_$boundary--
--_1_$boundary
Content-Type: application/octet-stream; name=\"$filename\" 
Content-Transfer-Encoding: base64 
Content-Disposition: attachment 

$attachment
--_1_$boundary--";

        mail($to, $subject, $message, $headers);
    }
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>MailFile</title>
</head>

<body>

<?php echo $output; ?>

<form enctype="multipart/form-data" action="<?php echo $_SERVER['PHP_SELF'];?>" method="post" <?php echo $flags;?>>
<p><label for="message">Message</label> <textarea name="message" id="message" cols="20" rows="8"></textarea></p>
<p><label for="file">File</label> <input type="file" name="file" id="file"></p>
<p><input type="submit" name="submit" id="submit" value="send"></p>
</form>
</body>
</html>

Very barebones really, and obviously the using inline CSS to hide the form is a bit cheap and you'd almost certainly want a bit more feedback to the user! Also, I'd probably spend a bit more time working out what the actual Content-Type for the file is, rather than cheating and using application/octet-stream but that part is quite as interesting.