#!/usr/bin/python
# -*- encoding: utf-8 -*-
#
# Microsoft Internet Explorer 5 can save a web pages as .mht files as an
# multi-part message in MIME format.
#
# This script reverts the process, decoding the attached files and saving
# them into a folder. The HTML content is modified to make all HREF relative
# and everything is placed in the same directory, index.html as root document.
# 
# I assume there is only a single HTML file in the message and I care only about
# images with extensions: jpg jpeg gif png bmp, other attachments are ignored.
#
# Usage:
# mht2html.py file.mht [more_files.mht]

import email
import os
import os.path
import sys

def convert(this):
  """Parses the file and extracts the HTML code and the attached images."""
  fin = open(this)
  msg = email.message_from_file(fin)
  fin.close()
  base = this[:this.rindex('.')]
  if msg.is_multipart():
    parts = msg.get_payload()
    html = parts[0].get_payload(decode = True)
    imgs = parts[1:]
    try:
      os.mkdir(base)
    except OSError, e:
      if e.errno != 17: # Exit if error unless file already exists, which is OK
        print "ERROR: Cannot create %s: %s" % (base, e)
        sys.exit(1)
    # Save the images, taking their filenames from their Content-Location header
    for img in [p for p in parts[1:] if p.get_content_maintype() == 'image']:
      location = [t[1] for t in img._headers if t[0] == 'Content-Location'][0]
      filename = os.path.basename(location)
      fd = open(os.path.join(base, filename), 'wb')
      fd.write(img.get_payload(decode = True))
      fd.close()
      # In the HTML content, replace the images location (full URL) for their file name
      html = html.replace(location, filename)
    # Save the HTML content into index.html
    fd = open(os.path.join(base, 'index.html'), 'w')
    fd.write(html)
    fd.close()
  else:
    fout = open(base + '.txt', 'w')
    msg.get_payload(fout, decode = True)
    fout.close()
  
if __name__ == '__main__':
  if len(sys.argv) == 0:
    print "Usage: %s file.mht [more_files.mht]" % sys.argv[0]
  for each in sys.argv[1:]:
    convert(each)