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imapsync/W/tools/fixup_email.py
Nick Bebout 137242e609 1.727
2016-09-19 10:17:24 -05:00

108 lines
4.1 KiB
Python
Executable File

#!/usr/bin/python
NUKE_HDRS = [
# (hdr, max_lines, max_items, max_bytes). (-1 => unlimited).
("References", 485, 485, 40000),
]
MAX_LINE_LENGTH = 996
NUKE_8BIT = True
FORCE_REWRITE = False
import sys
from email.parser import Parser
from email.generator import Generator
from email import utils
from cStringIO import StringIO
# NB: utils._qencode() replaces ALL ' ' with '=20', as required by QP
# header strings. We only need to encode trailing whitespace in message
# body. quopri.encodestring (used by utils._qencode()) does this already.
from quopri import encodestring as qp_encode
fp = open(sys.argv[1], "rb") if len(sys.argv) > 1 else sys.stdin
msg_text_crnl = fp.read(); fp.close()
msg_text_nl = msg_text_crnl.replace("\r\n", "\n")
# We want to preserve CRLF and any leading "From" from source message
CRLF = "\r\n" if (len(msg_text_nl) < len(msg_text_crnl)) else "\n"
UNIXFROM = msg_text_nl.startswith("From ")
def rewrite(part):
need_rewrite = False
for hdr in part.values():
if max([len(i) for i in hdr.split('\n')]) > MAX_LINE_LENGTH:
need_rewrite = True # Force MIME rewrite if we have long headers
sys.stderr.write("FIXUP NEXT: Rewrite forced by long header line\n")
for hdr, max_lines, max_items, max_bytes in NUKE_HDRS:
(hdr, val) = (hdr.lower(), msg.get(hdr))
if (val and ((max_lines >= 0 and len(val.split('\n')) > max_lines) or
(max_items >= 0 and len(val.split()) > max_items) or
(max_bytes >= 0 and len(val) > max_bytes))):
del msg[hdr]
sys.stderr.write("FIXUP NEXT: Removed long header line: "+hdr+"\n")
need_rewrite = True
if part.is_multipart():
for subpart in part.get_payload():
if rewrite(subpart):
need_rewrite = True
return need_rewrite
payload = part.get_payload()
max_line_length = max([ len(i) for i in payload.split('\n') ])
cte = part.get('content-transfer-encoding', '').lower().strip()
if cte in ['8bit', '7bit', 'binary', '']:
# Encode unencoded forms which contain 8bit characters or long lines
update_cte = part.replace_header if (cte != '') else part.add_header
nonascii_count = [(ord(c) >= 128) for c in payload].count(True)
if ((NUKE_8BIT and nonascii_count > 0) or
max_line_length > MAX_LINE_LENGTH):
if nonascii_count < 100:
part.set_payload(qp_encode(payload))
update_cte('Content-Transfer-Encoding', "quoted-printable")
else:
part.set_payload(utils._bencode(payload))
update_cte('Content-Transfer-Encoding', "base64")
need_rewrite = True
elif cte in ['quoted-printable', 'base64']:
# Recode quoted-printable or base64 with long lines
if max_line_length > MAX_LINE_LENGTH:
if cte == 'quoted-printable':
raw=utils._qdecode(payload)
part.set_payload(qp_encode(raw))
need_rewrite = True
elif cte == 'base64':
try:
raw=utils._bdecode(payload)
part.set_payload(utils._bencode(raw))
need_rewrite = True
except binascii.Error:
pass
newcte = part.get('content-transfer-encoding', '').lower().strip()
if (newcte != cte):
part.add_header('X-Mime-Autoconverted',
"from " + (cte or "none") + " to " + newcte)
sys.stderr.write("FIXUP NEXT: Attachment converted " +
"from " + (cte or "none") + " to " + newcte + "\n")
return need_rewrite
msg=Parser().parsestr(msg_text_nl)
if not rewrite(msg) and not FORCE_REWRITE:
sys.stdout.write(msg_text_crnl)
sys.exit(0)
buffer = StringIO()
gen=Generator(buffer, mangle_from_=False, maxheaderlen=MAX_LINE_LENGTH)
gen.flatten(msg, unixfrom=UNIXFROM)
buffer.seek(0)
for line in buffer.readlines():
sys.stdout.write(line.rstrip('\n')); sys.stdout.write(CRLF)
buffer.close()
sys.exit(0)