NAME

       Mail::SpamAssassin::Message - decode, render, and hold an RFC-2822 message

DESCRIPTION

       This module encapsulates an email message and allows access to the various MIME message parts and message
       metadata.

       The message structure, after initiating a parse() cycle, looks like this:

         Message object, also top-level node in Message::Node tree
            |
            +---> Message::Node for other parts in MIME structure
            |       |---> [ more Message::Node parts ... ]
            |       [ others ... ]
            |
            +---> Message::Metadata object to hold metadata

PUBLIC METHODS

       new()
           Creates a Mail::SpamAssassin::Message object.  Takes a hash reference as a parameter.  The used hash
           key/value pairs are as follows:

           "message" is either undef (which will use STDIN), a scalar - a string containing an entire message, a
           reference to such string, an array reference of the message with one line per array element, or
           either a file glob or an IO::File object which holds the entire contents of the message.

           Note: The message is expected to generally be in RFC 2822 format, optionally including an mbox
           message separator line (the "From " line) as the first line.

           "parse_now" specifies whether or not to create the MIME tree at object-creation time or later as
           necessary.

           The parse_now option, by default, is set to false (0).  This allows SpamAssassin to not have to
           generate the tree of Mail::SpamAssassin::Message::Node objects and their related data if the tree is
           not going to be used.  This is handy, for instance, when running "spamassassin -d", which only needs
           the pristine header and body which is always handled when the object is created.

           "subparse" specifies how many MIME recursion levels should be parsed.  Defaults to 20.

       find_parts()
           Used to search the tree for specific MIME parts.  See Mail::SpamAssassin::Message::Node for more
           details.

       get_pristine_header()
           Returns pristine headers of the message.  If no specific header name is given as a parameter (case-
           insensitive), then all headers will be returned as a scalar, including the blank line at the end of
           the headers.

           If called in an array context, an array will be returned with each specific header in a different
           element.  In a scalar context, the last specific header is returned.

           ie: If 'Subject' is specified as the header, and there are 2 Subject headers in a message, the
           last/bottom one in the message is returned in scalar context or both are returned in array context.

           Btw, returning the last header field (not the first) happens to be consistent with DKIM signatures,
           which search for and cover multiple header fields bottom-up according to the 'h' tag. Let's keep it
           this way.

           Note: the returned header will include the ending newline and any embedded whitespace folding.

       get_mbox_separator()
           Returns the mbox separator found in the message, or undef if there wasn't one.

       get_body()
           Returns an array of the pristine message body, one line per array element.

       get_pristine()
           Returns a scalar of the entire pristine message.

       get_pristine_body()
           Returns a scalar of the pristine message body.

       get_pristine_body_digest()
           Returns SHA1 hex digest of the pristine message body.  CRLF line endings are normalized to LF before
           hashing.

       get_msgid()
           Returns Message-ID header for the message, with <> and surrounding whitespace removed. Returns undef,
           if nothing found between <>.

       generate_msgid()
           Generate a calculated "Message-ID" in sha1hex@sa_generated format, using To, Date headers and
           pristine body as source for hashing.

       extract_message_metadata($permsgstatus)
       $str = get_metadata($hdr)
       put_metadata($hdr, $text)
       delete_metadata($hdr)
       $str = get_all_metadata()
       finish_metadata()
           Destroys the metadata for this message.  Once a message has been scanned fully, the metadata is no
           longer required.   Destroying this will free up some memory.

       finish()
           Clean up an object so that it can be destroyed.

       receive_date()
           Return a time_t value with the received date of the current message, or current time if received time
           couldn't be determined.

PARSING METHODS, NON-PUBLIC

       These methods take a RFC2822-esque formatted message and create a tree with all of the MIME body parts
       included.  Those parts will be decoded as necessary, and text/html parts will be rendered into a standard
       text format, suitable for use in SpamAssassin.

       parse_body()
           parse_body() passes the body part that was passed in onto the correct part parser, either
           _parse_multipart() for multipart/* parts, or _parse_normal() for everything else.  Multipart sections
           become the root of sub-trees, while everything else becomes a leaf in the tree.

           For multipart messages, the first call to parse_body() doesn't create a new sub-tree and just uses
           the parent node to contain children.  All other calls to parse_body() will cause a new sub-tree root
           to be created and children will exist underneath that root.  (this is just so the tree doesn't have a
           root node which points at the actual root node ...)

       _parse_multipart()
           Generate a root node, and for each child part call parse_body() to generate the tree.

       _parse_normal()
           Generate a leaf node and add it to the parent.