#!/usr/bin/env python
'''mailextract - Extract MIME encoded attached files from mail message

SYNOPSIS
    mailextract [-u] source [dest]

DESCRIPTION
    Reads mail message from source and extracts and decodes MIME attachments.

    If source is - then the mail message is read from stdin.  If dest is not
    specified then the extracted files are written to stdout.

    dest can specify either a destination directory for extracted files or a
    single file name for extracted files. If dest is a directory then the
    extracted files will will be written to dest using the file names specified
    in the mail message. If dest is a file name then extracted files will be
    concatenated to the dest file. If the MIME attachment has no name, the -u
    option is specified, and dest is a directory name then the saved file names
    will be part_N where N is the MIME part number 1,2,..

OPTIONS
    --help
        Print this documentation.

    -u
        Include unamed MIME parts. By default only parts with a (file) name are
        extracted.

AUTHOR
    Written by Stuart Rackham, <srackham@methods.co.nz>

COPYING
    Copyright (C) 2000 Stuart Rackham. Free use of this software is granted
    under the terms of the GNU General Public License (GPL).
'''

import sys, os, string, mimetools, multifile

'''Version History:
1.0     20 July 2000    Initial release.
1.0.1   22 July 2000    Added --help option.
'''
VERSION = "1.0.1"

error = "mailextract.error"

def mailextract(src, dstfile, dstdir=None, namedonly=1):
    '''Read mail message from src multifile object and write attached files
    to dstfile file object or dstdir directory.'''
    headers = mimetools.Message(src, src.seekable)
    if headers.getmaintype() != "multipart":
        raise error, "message is not multipart MIME"
    boundary = headers.getparam("boundary")
    if not boundary:
        raise error, "message boundary not specified"
    partno = 0
    src.push(boundary)
    src.read()          # Read to first boundary.
    while not src.last:
        src.next()
        headers = mimetools.Message(src, src.seekable)
        partno = partno + 1
        name = headers.getparam("name")
        if namedonly and not name:
            src.read()  # Read to next boundary.
            continue
        encoding = headers.getencoding()
        if not encoding:
            raise error, "unknown message encoding"
        if dstdir:
            if not name: name = "part_%d" % (partno,)
            dstfile = open(os.path.join(dstdir,name), "wb+")
        else:
            name = os.path.basename(dstfile.name)
        sys.stderr.write("saving part %d (%s encoding) to %s\n"
            % (partno, encoding, name))
        if encoding == "7bit":
            mimetools.copyliteral(src, dstfile)
        else:
            mimetools.decode(src, dstfile, encoding)
        if dstdir:
            dstfile.close()

def usage():
    cmd = os.path.basename(sys.argv[0])
    sys.stderr.write("Usage: %s [-u] [--help] source [dest]\n" % cmd)

def main():
    # Process command line options.
    import getopt
    opts,args = getopt.getopt(sys.argv[1:],"u",["help"])
    namedonly = 1
    for o,v in opts:
        if o == '--help':
            print __doc__
            sys.exit(0)
        if o == '-u':
            namedonly = 0
    if not 1 <= len(args) <= 2:
        usage()
        sys.exit(1)
    if args[0] == '-':
        source = sys.stdin
    else:
        source = open(args[0],"rb")
    if len(args) > 1 and args[1] != '-':
        dest = args[1]
    else:
        dest = None
    mf = multifile.MultiFile(source, 0)
    if not dest:
        mailextract(mf, sys.stdout, namedonly=namedonly)
    else:
        if os.path.isdir(dest):
            mailextract(mf, None, dest, namedonly=namedonly)
        else:
            dstdir,dstfile = os.path.split(dest)
            if dstdir and not os.path.isdir(dstdir):
                raise error,"path %s not found" % dstdir
            f = open(dest, "wb+")
            mailextract(mf, f, namedonly=namedonly)
            f.close()
    source.close()

if __name__ == "__main__":
    try:
        main()
    except (KeyboardInterrupt, SystemExit):
        pass
    except:
        sys.stderr.write("%s: %s\n" %
            (os.path.basename(sys.argv[0]), sys.exc_info()[1]))