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# encoding=utf-8
# Copyright (C) 2011-2012 Patrick Totzke <patricktotzke@gmail.com>
# Copyright © 2017 Dylan Baker <dylan@pnwbakers.com>
# This file is released under the GNU GPL, version 3 or a later revision.
# For further details see the COPYING file
import os
import email
import email.charset as charset
import email.policy
import email.utils
import tempfile
import logging
import mailcap
from .. import helper
from ..settings.const import settings
from ..helper import string_sanitize
from ..helper import parse_mailcap_nametemplate
from ..helper import split_commandstring
charset.add_charset('utf-8', charset.QP, charset.QP, 'utf-8')
def render_part(part, field_key='copiousoutput'):
"""
renders a non-multipart email part into displayable plaintext by piping its
payload through an external script. The handler itself is determined by
the mailcap entry for this part's ctype.
"""
ctype = part.get_content_type()
raw_payload = remove_cte(part)
rendered_payload = None
# get mime handler
_, entry = settings.mailcap_find_match(ctype, key=field_key)
if entry is not None:
tempfile_name = None
stdin = None
handler_raw_commandstring = entry['view']
# in case the mailcap defined command contains no '%s',
# we pipe the files content to the handling command via stdin
if '%s' in handler_raw_commandstring:
# open tempfile, respect mailcaps nametemplate
nametemplate = entry.get('nametemplate', '%s')
prefix, suffix = parse_mailcap_nametemplate(nametemplate)
with tempfile.NamedTemporaryFile(
delete=False, prefix=prefix, suffix=suffix) \
as tmpfile:
tmpfile.write(raw_payload)
tempfile_name = tmpfile.name
else:
stdin = raw_payload
# read parameter, create handler command
parms = tuple('='.join(p) for p in part.get_params())
# create and call external command
cmd = mailcap.subst(entry['view'], ctype,
filename=tempfile_name, plist=parms)
logging.debug('command: %s', cmd)
logging.debug('parms: %s', str(parms))
cmdlist = split_commandstring(cmd)
# call handler
stdout, _, _ = helper.call_cmd(cmdlist, stdin=stdin)
if stdout:
rendered_payload = stdout
# remove tempfile
if tempfile_name:
os.unlink(tempfile_name)
return rendered_payload
def remove_cte(part, as_string=False):
"""Interpret MIME-part according to it's Content-Transfer-Encodings.
This returns the payload of `part` as string or bytestring for display, or
to be passed to an external program. In the raw file the payload may be
encoded, e.g. in base64, quoted-printable, 7bit, or 8bit. This method will
look for one of the above Content-Transfer-Encoding header and interpret
the payload accordingly.
Incorrect header values (common in spam messages) will be interpreted as
lenient as possible and will result in INFO-level debug messages.
..Note:: All this may be depricated in favour of
`email.contentmanager.raw_data_manager` (v3.6+)
:param email.message.EmailMessage part: The part to decode
:param bool as_string: If true return a str, otherwise return bytes
:returns: The mail with any Content-Transfer-Encoding removed
:rtype: Union[str, bytes]
"""
payload = part.get_payload(decode = True)
if as_string:
enc = part.get_content_charset('ascii')
if enc.startswith('windows-'):
enc = enc.replace('windows-', 'cp', 1)
try:
payload = payload.decode(enc, errors = 'backslashreplace')
except LookupError:
# enc is unknown;
# fall back to guessing the correct encoding using libmagic
payload = helper.try_decode(payload)
except UnicodeDecodeError as emsg:
# the mail contains chars that are not enc-encoded.
# libmagic works better than just ignoring those
logging.debug('Decoding failure: {}'.format(emsg))
payload = helper.try_decode(payload)
return payload
MISSING_HTML_MSG = ("This message contains a text/html part that was not "
"rendered due to a missing mailcap entry. "
"Please refer to item 5 in our FAQ: "
"http://alot.rtfd.io/en/latest/faq.html")
def extract_body(mail):
"""Returns a string view of a Message.
This consults :ref:`prefer_plaintext <prefer-plaintext>`
to determine if a "text/plain" alternative is preferred over a "text/html"
part.
:param mail: the mail to use
:type mail: :class:`email.message.EmailMessage`
:returns: The combined text of any parts to be used
:rtype: str
"""
if settings.get('prefer_plaintext'):
preferencelist = ('plain', 'html')
else:
preferencelist = ('html', 'plain')
body_part = mail.get_body(preferencelist)
if body_part is None: # if no part matching preferredlist was found
return ""
displaystring = ""
if body_part.get_content_type() == 'text/plain':
displaystring = string_sanitize(remove_cte(body_part, as_string=True))
else:
rendered_payload = render_part(body_part)
if rendered_payload: # handler had output
displaystring = string_sanitize(rendered_payload)
else:
if body_part.get_content_type() == 'text/html':
displaystring = MISSING_HTML_MSG
return displaystring
def formataddr(pair):
""" this is the inverse of email.utils.parseaddr:
other than email.utils.formataddr, this
- *will not* re-encode unicode strings, and
- *will* re-introduce quotes around real names containing commas
"""
name, address = pair
if not name:
return address
elif ',' in name:
name = "\"" + name + "\""
return "{0} <{1}>".format(name, address)
def is_subdir_of(subpath, superpath):
# make both absolute
superpath = os.path.realpath(superpath)
subpath = os.path.realpath(subpath)
# return true, if the common prefix of both is equal to directory
# e.g. /a/b/c/d.rst and directory is /a/b, the common prefix is /a/b
return os.path.commonprefix([subpath, superpath]) == superpath
def clear_my_address(my_account, value):
"""return recipient header without the addresses in my_account
:param my_account: my account
:type my_account: :class:`Account`
:param value: a list of recipient or sender strings (with or without
real names as taken from email headers)
:type value: list(str)
:returns: a new, potentially shortend list
:rtype: list(str)
"""
new_value = []
for name, address in email.utils.getaddresses(value):
if not my_account.matches_address(address):
new_value.append(formataddr((name, address)))
return new_value
def ensure_unique_address(recipients):
"""
clean up a list of name,address pairs so that
no address appears multiple times.
"""
res = dict()
for name, address in email.utils.getaddresses(recipients):
res[address] = name
logging.debug(res)
urecipients = [formataddr((n, a)) for a, n in res.items()]
return sorted(urecipients)
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