mailparse_msg_get_part

A multi-part e-mail message can exists out of different parts.
Like:
Array
(
 [0] => 1
 [1] => 1.1
 [2] => 1.1.1
 [3] => 1.1.2
 [4] => 1.2
)
Each part is a section in the mail message. To loop through every part of the message you need to go like this:
$mime_part = mailparse_msg_get_part($this->message, "1.2"); //1.2 is the binary base64 encoded part of the attachement
 
$body_parts = mailparse_msg_get_part_data($mime_part); 
Body part looks like this:
Array
(
 [headers] => Array
 (
 [content-type] => application/x-zip-compressed; name="3000_000000.txt"
 [content-disposition] => attachment; filename="3000_000000.txt"
 [content-transfer-encoding] => base64
 [x-attachment-id] => b31f1a24358e7e5_0.1
 )
 [starting-pos] => 4513
 [starting-pos-body] => 4736
 [ending-pos] => 4772
 [ending-pos-body] => 4772
 [line-count] => 6
 [body-line-count] => 0
 [charset] => us-ascii
 [transfer-encoding] => base64
 [content-name] => 3000_000000.sbd
 [content-type] => application/x-zip-compressed
 [disposition-filename] => 3000_000000.sbd
 [content-disposition] => attachment
 [content-base] => /
)