Module to convert a mail message to or from quoted-printable. The

message may consist of several MIME parts in which case each part is
converted independent of the others.  Only converts when necessary.

Lib/mimify.py

+#!/usr/local/bin/python
+
+'''Mimification and unmimification of mail messages.
+
+decode quoted-printable parts of a mail message or encode using
+quoted-printable.
+
+Usage:
+	mimify(input, output)
+	unmimify(input, output)
+to encode and decode respectively.  Input and output may be the name
+of a file or an open file object.  Only a readline() method is used
+on the input file, only a write() method is used on the output file.
+When using file names, the input and output file names may be the
+same.
+
+Interactive usage:
+	mimify.py -e [infile [outfile]]
+	mimify.py -d [infile [outfile]]
+to encode and decode respectively.  Infile defaults to standard
+input and outfile to standard output.
+'''
+
+# Configure
+MAXLEN = 200	# if lines longer than this, encode as quoted-printable
+CHARSET = 'ISO-8859-1'	# default charset for non-US-ASCII mail
+QUOTE = '> '		# string replies are quoted with
+# End configure
+
+import regex, regsub, string
+
+qp = regex.compile('^content-transfer-encoding:[\000-\377]*quoted-printable',
+		   regex.casefold)
+mp = regex.compile('^content-type:[\000-\377]*multipart/[\000-\377]*boundary="?\\([^;"\n]*\\)',
+		   regex.casefold)
+chrset = regex.compile('^\\(content-type:.*charset="\\)\\(us-ascii\\|iso-8859-[0-9]+\\)\\("[\000-\377]*\\)',
+		       regex.casefold)
+he = regex.compile('^-*$')
+mime_code = regex.compile('=\\([0-9a-f][0-9a-f]\\)', regex.casefold)
+mime_head = regex.compile('=\\?iso-8859-1\\?q\\?\\([^?]+\\)\\?=',
+			  regex.casefold)
+repl = regex.compile('^subject:[ \t]+re: ', regex.casefold)
+
+class File:
+	'''A simple fake file object that knows about limited
+	   read-ahead and boundaries.
+	   The only supported method is readline().'''
+
+	def __init__(self, file, boundary):
+		self.file = file
+		self.boundary = boundary
+		self.peek = None
+
+	def readline(self):
+		if self.peek is not None:
+			return ''
+		line = self.file.readline()
+		if not line:
+			return line
+		if self.boundary:
+			if line == self.boundary + '\n':
+				self.peek = line
+				return ''
+			if line == self.boundary + '--\n':
+				self.peek = line
+				return ''
+		return line
+
+class HeaderFile:
+	def __init__(self, file):
+		self.file = file
+		self.peek = None
+
+	def readline(self):
+		if self.peek is not None:
+			line = self.peek
+			self.peek = None
+		else:
+			line = self.file.readline()
+		if not line:
+			return line
+		if he.match(line) >= 0:
+			return line
+		while 1:
+			self.peek = self.file.readline()
+			if len(self.peek) == 0 or \
+			   (self.peek[0] != ' ' and self.peek[0] != '\t'):
+				return line
+			line = line + self.peek
+			self.peek = None
+
+def mime_decode(line):
+	'''Decode a single line of quoted-printable text to 8bit.'''
+	newline = ''
+	while 1:
+		i = mime_code.search(line)
+		if i < 0:
+			break
+		newline = newline + line[:i] + \
+			  chr(string.atoi(mime_code.group(1), 16))
+		line = line[i+3:]
+	return newline + line
+
+def mime_decode_header(line):
+	'''Decode a header line to 8bit.'''
+	newline = ''
+	while 1:
+		i = mime_head.search(line)
+		if i < 0:
+			break
+		match = mime_head.group(0, 1)
+		newline = newline + line[:i] + mime_decode(match[1])
+		line = line[i + len(match[0]):]
+	return newline + line
+
+def unmimify_part(ifile, ofile):
+	'''Convert a quoted-printable part of a MIME mail message to 8bit.'''
+	multipart = None
+	quoted_printable = 0
+	is_repl = 0
+	if ifile.boundary and ifile.boundary[:2] == QUOTE:
+		prefix = QUOTE
+	else:
+		prefix = ''
+
+	# read header
+	hfile = HeaderFile(ifile)
+	while 1:
+		line = hfile.readline()
+		if not line:
+			return
+		if prefix and line[:len(prefix)] == prefix:
+			line = line[len(prefix):]
+			pref = prefix
+		else:
+			pref = ''
+		line = mime_decode_header(line)
+		if qp.match(line) >= 0:
+			quoted_printable = 1
+			continue	# skip this header
+		ofile.write(pref + line)
+		if not prefix and repl.match(line) >= 0:
+			# we're dealing with a reply message
+			is_repl = 1
+		if mp.match(line) >= 0:
+			multipart = '--' + mp.group(1)
+		if he.match(line) >= 0:
+			break
+	if is_repl and (quoted_printable or multipart):
+		is_repl = 0
+
+	# read body
+	while 1:
+		line = ifile.readline()
+		if not line:
+			return
+		line = regsub.gsub(mime_head, '\\1', line)
+		if prefix and line[:len(prefix)] == prefix:
+			line = line[len(prefix):]
+			pref = prefix
+		else:
+			pref = ''
+##		if is_repl and len(line) >= 4 and line[:4] == QUOTE+'--' and line[-3:] != '--\n':
+##			multipart = line[:-1]
+		while multipart:
+			if line == multipart + '--\n':
+				ofile.write(pref + line)
+				multipart = None
+				line = None
+				break
+			if line == multipart + '\n':
+				ofile.write(pref + line)
+				nifile = File(ifile, multipart)
+				unmimify_part(nifile, ofile)
+				line = nifile.peek
+				continue
+			# not a boundary between parts
+			break
+		if line and quoted_printable:
+			while line[-2:] == '=\n':
+				line = line[:-2]
+				newline = ifile.readline()
+				if newline[:len(QUOTE)] == QUOTE:
+					newline = newline[len(QUOTE):]
+				line = line + newline
+			line = mime_decode(line)
+		if line:
+			ofile.write(pref + line)
+
+def unmimify(infile, outfile):
+	'''Convert quoted-printable parts of a MIME mail message to 8bit.'''
+	if type(infile) == type(''):
+		ifile = open(infile)
+		if type(outfile) == type('') and infile == outfile:
+			import os
+			d, f = os.path.split(infile)
+			os.rename(infile, os.path.join(d, ',' + f))
+	else:
+		ifile = infile
+	if type(outfile) == type(''):
+		ofile = open(outfile, 'w')
+	else:
+		ofile = outfile
+	nifile = File(ifile, None)
+	unmimify_part(nifile, ofile)
+	ofile.flush()
+
+mime_char = regex.compile('[=\240-\377]') # quote these chars in body
+mime_header_char = regex.compile('[=?\240-\377]') # quote these in header
+
+def mime_encode(line, header):
+	'''Code a single line as quoted-printable.
+	   If header is set, quote some extra characters.'''
+	if header:
+		reg = mime_header_char
+	else:
+		reg = mime_char
+	newline = ''
+	if len(line) >= 5 and line[:5] == 'From ':
+		# quote 'From ' at the start of a line for stupid mailers
+		newline = string.upper('=%02x' % ord('F'))
+		line = line[1:]
+	while 1:
+		i = reg.search(line)
+		if i < 0:
+			break
+		newline = newline + line[:i] + \
+			  string.upper('=%02x' % ord(line[i]))
+		line = line[i+1:]
+	line = newline + line
+
+	newline = ''
+	while len(line) >= 75:
+		i = 73
+		while line[i] == '=' or line[i-1] == '=':
+			i = i - 1
+		i = i + 1
+		newline = newline + line[:i] + '=\n'
+		line = line[i:]
+	return newline + line
+
+mime_header = regex.compile('\\([ \t(]\\)\\([-a-zA-Z0-9_+]*[\240-\377][-a-zA-Z0-9_+\240-\377]*\\)\\([ \t)]\\|$\\)')
+
+def mime_encode_header(line):
+	'''Code a single header line as quoted-printable.'''
+	newline = ''
+	while 1:
+		i = mime_header.search(line)
+		if i < 0:
+			break
+		newline = newline + line[:i] + mime_header.group(1) + \
+			  '=?' + CHARSET + '?Q?' + \
+			  mime_encode(mime_header.group(2), 1) + \
+			  '?=' + mime_header.group(3)
+		line = line[i+len(mime_header.group(0)):]
+	return newline + line
+
+mv = regex.compile('^mime-version:', regex.casefold)
+cte = regex.compile('^content-transfer-encoding:', regex.casefold)
+iso_char = regex.compile('[\240-\377]')
+
+def mimify_part(ifile, ofile, is_mime):
+	'''Convert an 8bit part of a MIME mail message to quoted-printable.'''
+	has_cte = is_qp = 0
+	multipart = None
+	must_quote_body = must_quote_header = has_iso_chars = 0
+
+	header = []
+	header_end = ''
+	message = []
+	message_end = ''
+	# read header
+	hfile = HeaderFile(ifile)
+	while 1:
+		line = hfile.readline()
+		if not line:
+			break
+		if not must_quote_header and iso_char.search(line) >= 0:
+			must_quote_header = 1
+		if mv.match(line) >= 0:
+			is_mime = 1
+		if cte.match(line) >= 0:
+			has_cte = 1
+			if qp.match(line) >= 0:
+				is_qp = 1
+		if mp.match(line) >= 0:
+			multipart = '--' + mp.group(1)
+		if he.match(line) >= 0:
+			header_end = line
+			break
+		header.append(line)
+
+	# read body
+	while 1:
+		line = ifile.readline()
+		if not line:
+			break
+		if multipart:
+			if line == multipart + '--\n':
+				message_end = line
+				break
+			if line == multipart + '\n':
+				message_end = line
+				break
+		if is_qp:
+			while line[-2:] == '=\n':
+				line = line[:-2]
+				newline = ifile.readline()
+				if newline[:len(QUOTE)] == QUOTE:
+					newline = newline[len(QUOTE):]
+				line = line + newline
+			line = mime_decode(line)
+		message.append(line)
+		if not has_iso_chars:
+			if iso_char.search(line) >= 0:
+				has_iso_chars = must_quote_body = 1
+		if not must_quote_body:
+			if len(line) > MAXLEN:
+				must_quote_body = 1
+
+	# convert and output header and body
+	for line in header:
+		if must_quote_header:
+			line = mime_encode_header(line)
+		if chrset.match(line) >= 0:
+			if has_iso_chars:
+				# change us-ascii into iso-8859-1
+				if string.lower(chrset.group(2)) == 'us-ascii':
+					line = chrset.group(1) + \
+					       CHARSET + chrset.group(3)
+			else:
+				# change iso-8859-* into us-ascii
+				line = chrset.group(1) + 'us-ascii' + chrset.group(3)
+		if has_cte and cte.match(line) >= 0:
+			line = 'Content-Transfer-Encoding: '
+			if must_quote_body:
+				line = line + 'quoted-printable\n'
+			else:
+				line = line + '7bit\n'
+		ofile.write(line)
+	if (must_quote_header or must_quote_body) and not is_mime:
+		ofile.write('Mime-Version: 1.0\n')
+		ofile.write('Content-Type: text/plain; ')
+		if has_iso_chars:
+			ofile.write('charset="%s"\n' % CHARSET)
+		else:
+			ofile.write('charset="us-ascii"\n')
+	if must_quote_body and not has_cte:
+		ofile.write('Content-Transfer-Encoding: quoted-printable\n')
+	ofile.write(header_end)
+
+	for line in message:
+		if must_quote_body:
+			line = mime_encode(line, 0)
+		ofile.write(line)
+	ofile.write(message_end)
+
+	line = message_end
+	while multipart:
+		if line == multipart + '--\n':
+			return
+		if line == multipart + '\n':
+			nifile = File(ifile, multipart)
+			mimify_part(nifile, ofile, 1)
+			line = nifile.peek
+			ofile.write(line)
+			continue
+
+def mimify(infile, outfile):
+	'''Convert 8bit parts of a MIME mail message to quoted-printable.'''
+	if type(infile) == type(''):
+		ifile = open(infile)
+		if type(outfile) == type('') and infile == outfile:
+			import os
+			d, f = os.path.split(infile)
+			os.rename(infile, os.path.join(d, ',' + f))
+	else:
+		ifile = infile
+	if type(outfile) == type(''):
+		ofile = open(outfile, 'w')
+	else:
+		ofile = outfile
+	nifile = File(ifile, None)
+	mimify_part(nifile, ofile, 0)
+	ofile.flush()
+
+import sys
+if __name__ == '__main__' or (len(sys.argv) > 0 and sys.argv[0] == 'mimify'):
+	import getopt
+	usage = 'Usage: mimify [-l len] -[ed] [infile [outfile]]'
+
+	opts, args = getopt.getopt(sys.argv[1:], 'l:ed')
+	if len(args) not in (0, 1, 2):
+		print usage
+		sys.exit(1)
+	if (('-e', '') in opts) == (('-d', '') in opts):
+		print usage
+		sys.exit(1)
+	for o, a in opts:
+		if o == '-e':
+			encode = mimify
+		elif o == '-d':
+			encode = unmimify
+		elif o == '-l':
+			try:
+				MAXLEN = string.atoi(a)
+			except:
+				print usage
+				sys.exit(1)
+	if len(args) == 0:
+		encode(sys.stdin, sys.stdout)
+	elif len(args) == 1:
+		encode(args[0], sys.stdout)
+	else:
+		encode(args[0], args[1])