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# Copyright (C) 2014 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# GNU Mailman. If not, see <http://www.gnu.org/licenses/>.
"""Subject header prefix munging."""
from __future__ import absolute_import, print_function, unicode_literals
__metaclass__ = type
__all__ = [
'SubjectPrefix',
]
import re
from email.header import Header, make_header, decode_header
from mailman.core.i18n import _
from mailman.interfaces.handler import IHandler
from zope.interface import implementer
RE_PATTERN = '((RE|AW|SV|VS)(\[\d+\])?:\s*)+'
ASCII_CHARSETS = (None, 'ascii', 'us-ascii')
EMPTYSTRING = ''
def ascii_header(mlist, msgdata, subject, prefix, prefix_pattern, ws):
if mlist.preferred_language.charset not in ASCII_CHARSETS:
return None
for chunk, charset in decode_header(subject.encode()):
if charset not in ASCII_CHARSETS:
return None
subject_text = EMPTYSTRING.join(str(subject).splitlines())
rematch = re.match(RE_PATTERN, subject_text, re.I)
if rematch:
subject_text = subject_text[rematch.end():]
recolon = 'Re: '
else:
recolon = ''
# At this point, the subject may become null if someone posted mail
# with "Subject: [subject prefix]".
if subject_text.strip() == '':
with _.using(mlist.preferred_language.code):
subject_text = _('(no subject)')
else:
subject_text = re.sub(prefix_pattern, '', subject_text)
msgdata['stripped_subject'] = subject_text
lines = subject_text.splitlines()
first_line = [lines[0]]
if recolon:
first_line.insert(0, recolon)
if prefix:
first_line.insert(0, prefix)
subject_text = EMPTYSTRING.join(first_line)
return Header(subject_text, continuation_ws=ws)
def all_same_charset(mlist, msgdata, subject, prefix, prefix_pattern, ws):
list_charset = mlist.preferred_language.charset
chunks = []
for chunk, charset in decode_header(subject.encode()):
if charset is None:
charset = 'us-ascii'
chunks.append(chunk.decode(charset))
if charset != list_charset:
return None
subject_text = EMPTYSTRING.join(chunks)
rematch = re.match(RE_PATTERN, subject_text, re.I)
if rematch:
subject_text = subject_text[rematch.end():]
recolon = 'Re: '
else:
recolon = ''
# At this point, the subject may become null if someone posted mail
# with "Subject: [subject prefix]".
if subject_text.strip() == '':
with _.push(mlist.preferred_language.code):
subject_text = _('(no subject)')
else:
subject_text = re.sub(prefix_pattern, '', subject_text)
msgdata['stripped_subject'] = subject_text
lines = subject_text.splitlines()
first_line = [lines[0]]
if recolon:
first_line.insert(0, recolon)
if prefix:
first_line.insert(0, prefix)
subject_text = EMPTYSTRING.join(first_line)
return Header(subject_text, charset=list_charset, continuation_ws=ws)
def mixed_charsets(mlist, msgdata, subject, prefix, prefix_pattern, ws):
list_charset = mlist.preferred_language.charset
chunks = decode_header(subject.encode())
if len(chunks) == 0:
with _.push(mlist.preferred_language.code):
subject_text = _('(no subject)')
chunks = [(prefix, list_charset),
(subject_text, list_charset),
]
return make_header(chunks, continuation_ws=ws)
# Only search the first chunk for Re and existing prefix.
chunk_text, chunk_charset = chunks[0]
if chunk_charset is None:
chunk_charset = 'us-ascii'
first_text = chunk_text.decode(chunk_charset)
first_text = re.sub(prefix_pattern, '', first_text).lstrip()
rematch = re.match(RE_PATTERN, first_text, re.I)
if rematch:
first_text = 'Re: ' + first_text[rematch.end():]
chunks[0] = (first_text, chunk_charset)
# The subject text stripped of the prefix, for use in the NNTP gateway.
msgdata['stripped_subject'] = str(make_header(chunks, continuation_ws=ws))
chunks.insert(0, (prefix, list_charset))
return make_header(chunks, continuation_ws=ws)
@implementer(IHandler)
class SubjectPrefix:
"""Add a list-specific prefix to the Subject header value."""
name = 'subject-prefix'
description = _('Add a list-specific prefix to the Subject header value.')
def process(self, mlist, msg, msgdata):
"""See `IHandler`."""
if msgdata.get('isdigest') or msgdata.get('_fasttrack'):
return
prefix = mlist.subject_prefix
if not prefix.strip():
return
subject = msg.get('subject', '')
# Turn the value into a Header instance and try to figure out what
# continuation whitespace is being used.
# Save the original Subject.
msgdata['original_subject'] = subject
if isinstance(subject, Header):
subject_text = str(subject)
else:
subject = make_header(decode_header(subject))
subject_text = str(subject)
lines = subject_text.splitlines()
ws = '\t'
if len(lines) > 1 and lines[1] and lines[1][0] in ' \t':
ws = lines[1][0]
# If the subject_prefix contains '%d', it is replaced with the mailing
# list's sequence number. The sequential number format allows '%d' or
# '%05d' like pattern.
prefix_pattern = re.escape(prefix)
# Unescape '%'.
prefix_pattern = '%'.join(prefix_pattern.split(r'\%'))
p = re.compile('%\d*d')
if p.search(prefix, 1):
# The prefix has number, so we should search prefix w/number in
# subject. Also, force new style.
prefix_pattern = p.sub(r'\s*\d+\s*', prefix_pattern)
# Substitute %d in prefix with post_id
try:
prefix = prefix % mlist.post_id
except TypeError:
pass
for handler in (ascii_header,
all_same_charset,
mixed_charsets,
):
new_subject = handler(
mlist, msgdata, subject, prefix, prefix_pattern, ws)
if new_subject is not None:
del msg['subject']
msg['Subject'] = new_subject
return
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