Mail::Message Module: Header Manipulations

dup_header() method duplicates only header part of a chain and left the body part as it is. The new chain has different head (header object) but others begining from the second part is same as the original chain.

              |<--------------- mail body ------------->
header0 ----> part1 -> part2 -> ...
               A
               |
dup_header0 ---

whole_message_header() returns the header object of the chain. The return value is a Mail::Message object not string.

header_data_type() returns the type of the whole message as string. It tells whether this message is text or multipart.