cpython/Lib/email/utils.py

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# Copyright (C) 2001-2006 Python Software Foundation
# Author: Barry Warsaw
# Contact: email-sig@python.org
"""Miscellaneous utilities."""
__all__ = [
'collapse_rfc2231_value',
'decode_params',
'decode_rfc2231',
'encode_rfc2231',
'formataddr',
'formatdate',
'getaddresses',
'make_msgid',
'parseaddr',
'parsedate',
'parsedate_tz',
'unquote',
]
import os
import re
import time
import base64
import random
import socket
import urllib
import warnings
from cStringIO import StringIO
from email._parseaddr import quote
from email._parseaddr import AddressList as _AddressList
from email._parseaddr import mktime_tz
# We need wormarounds for bugs in these methods in older Pythons (see below)
from email._parseaddr import parsedate as _parsedate
from email._parseaddr import parsedate_tz as _parsedate_tz
from quopri import decodestring as _qdecode
# Intrapackage imports
from email.encoders import _bencode, _qencode
COMMASPACE = ', '
EMPTYSTRING = ''
UEMPTYSTRING = u''
CRLF = '\r\n'
TICK = "'"
specialsre = re.compile(r'[][\\()<>@,:;".]')
escapesre = re.compile(r'[][\\()"]')
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# Helpers
def _identity(s):
return s
def _bdecode(s):
# We can't quite use base64.encodestring() since it tacks on a "courtesy
# newline". Blech!
if not s:
return s
value = base64.decodestring(s)
if not s.endswith('\n') and value.endswith('\n'):
return value[:-1]
return value
def fix_eols(s):
"""Replace all line-ending characters with \r\n."""
# Fix newlines with no preceding carriage return
s = re.sub(r'(?<!\r)\n', CRLF, s)
# Fix carriage returns with no following newline
s = re.sub(r'\r(?!\n)', CRLF, s)
return s
def formataddr(pair):
"""The inverse of parseaddr(), this takes a 2-tuple of the form
(realname, email_address) and returns the string value suitable
for an RFC 2822 From, To or Cc header.
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If the first element of pair is false, then the second element is
returned unmodified.
"""
name, address = pair
if name:
quotes = ''
if specialsre.search(name):
quotes = '"'
name = escapesre.sub(r'\\\g<0>', name)
return '%s%s%s <%s>' % (quotes, name, quotes, address)
return address
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def getaddresses(fieldvalues):
"""Return a list of (REALNAME, EMAIL) for each fieldvalue."""
all = COMMASPACE.join(fieldvalues)
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a = _AddressList(all)
return a.addresslist
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ecre = re.compile(r'''
=\? # literal =?
(?P<charset>[^?]*?) # non-greedy up to the next ? is the charset
\? # literal ?
(?P<encoding>[qb]) # either a "q" or a "b", case insensitive
\? # literal ?
(?P<atom>.*?) # non-greedy up to the next ?= is the atom
\?= # literal ?=
''', re.VERBOSE | re.IGNORECASE)
def formatdate(timeval=None, localtime=False, usegmt=False):
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"""Returns a date string as specified by RFC 2822, e.g.:
Fri, 09 Nov 2001 01:08:47 -0000
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Optional timeval if given is a floating point time value as accepted by
gmtime() and localtime(), otherwise the current time is used.
Optional localtime is a flag that when True, interprets timeval, and
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returns a date relative to the local timezone instead of UTC, properly
taking daylight savings time into account.
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Optional argument usegmt means that the timezone is written out as
an ascii string, not numeric one (so "GMT" instead of "+0000"). This
is needed for HTTP, and is only used when localtime==False.
"""
# Note: we cannot use strftime() because that honors the locale and RFC
# 2822 requires that day and month names be the English abbreviations.
if timeval is None:
timeval = time.time()
if localtime:
now = time.localtime(timeval)
# Calculate timezone offset, based on whether the local zone has
# daylight savings time, and whether DST is in effect.
if time.daylight and now[-1]:
offset = time.altzone
else:
offset = time.timezone
hours, minutes = divmod(abs(offset), 3600)
# Remember offset is in seconds west of UTC, but the timezone is in
# minutes east of UTC, so the signs differ.
if offset > 0:
sign = '-'
else:
sign = '+'
zone = '%s%02d%02d' % (sign, hours, minutes // 60)
else:
now = time.gmtime(timeval)
# Timezone offset is always -0000
if usegmt:
zone = 'GMT'
else:
zone = '-0000'
return '%s, %02d %s %04d %02d:%02d:%02d %s' % (
['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'][now[6]],
now[2],
['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'][now[1] - 1],
now[0], now[3], now[4], now[5],
zone)
def make_msgid(idstring=None):
"""Returns a string suitable for RFC 2822 compliant Message-ID, e.g:
<20020201195627.33539.96671@nightshade.la.mastaler.com>
Optional idstring if given is a string used to strengthen the
uniqueness of the message id.
"""
timeval = time.time()
utcdate = time.strftime('%Y%m%d%H%M%S', time.gmtime(timeval))
pid = os.getpid()
randint = random.randrange(100000)
if idstring is None:
idstring = ''
else:
idstring = '.' + idstring
idhost = socket.getfqdn()
msgid = '<%s.%s.%s%s@%s>' % (utcdate, pid, randint, idstring, idhost)
return msgid
# These functions are in the standalone mimelib version only because they've
# subsequently been fixed in the latest Python versions. We use this to worm
# around broken older Pythons.
def parsedate(data):
if not data:
return None
return _parsedate(data)
def parsedate_tz(data):
if not data:
return None
return _parsedate_tz(data)
def parseaddr(addr):
addrs = _AddressList(addr).addresslist
if not addrs:
return '', ''
return addrs[0]
# rfc822.unquote() doesn't properly de-backslash-ify in Python pre-2.3.
def unquote(str):
"""Remove quotes from a string."""
if len(str) > 1:
if str.startswith('"') and str.endswith('"'):
return str[1:-1].replace('\\\\', '\\').replace('\\"', '"')
if str.startswith('<') and str.endswith('>'):
return str[1:-1]
return str
# RFC2231-related functions - parameter encoding and decoding
def decode_rfc2231(s):
"""Decode string according to RFC 2231"""
parts = s.split(TICK, 2)
if len(parts) <= 2:
return None, None, s
if len(parts) > 3:
charset, language = parts[:2]
s = TICK.join(parts[2:])
return charset, language, s
return parts
def encode_rfc2231(s, charset=None, language=None):
"""Encode string according to RFC 2231.
If neither charset nor language is given, then s is returned as-is. If
charset is given but not language, the string is encoded using the empty
string for language.
"""
import urllib
s = urllib.quote(s, safe='')
if charset is None and language is None:
return s
if language is None:
language = ''
return "%s'%s'%s" % (charset, language, s)
rfc2231_continuation = re.compile(r'^(?P<name>\w+)\*((?P<num>[0-9]+)\*?)?$')
def decode_params(params):
"""Decode parameters list according to RFC 2231.
params is a sequence of 2-tuples containing (param name, string value).
"""
# Copy params so we don't mess with the original
params = params[:]
new_params = []
# Map parameter's name to a list of continuations. The values are a
# 3-tuple of the continuation number, the string value, and a flag
# specifying whether a particular segment is %-encoded.
rfc2231_params = {}
name, value = params.pop(0)
new_params.append((name, value))
while params:
name, value = params.pop(0)
if name.endswith('*'):
encoded = True
else:
encoded = False
value = unquote(value)
mo = rfc2231_continuation.match(name)
if mo:
name, num = mo.group('name', 'num')
if num is not None:
num = int(num)
rfc2231_params.setdefault(name, []).append((num, value, encoded))
else:
new_params.append((name, '"%s"' % quote(value)))
if rfc2231_params:
for name, continuations in rfc2231_params.items():
value = []
extended = False
# Sort by number
continuations.sort()
# And now append all values in numerical order, converting
# %-encodings for the encoded segments. If any of the
# continuation names ends in a *, then the entire string, after
# decoding segments and concatenating, must have the charset and
# language specifiers at the beginning of the string.
for num, s, encoded in continuations:
if encoded:
s = urllib.unquote(s)
extended = True
value.append(s)
value = quote(EMPTYSTRING.join(value))
if extended:
charset, language, value = decode_rfc2231(value)
new_params.append((name, (charset, language, '"%s"' % value)))
else:
new_params.append((name, '"%s"' % value))
return new_params
def collapse_rfc2231_value(value, errors='replace',
fallback_charset='us-ascii'):
if isinstance(value, tuple):
rawval = unquote(value[2])
charset = value[0] or 'us-ascii'
try:
return unicode(rawval, charset, errors)
except LookupError:
# XXX charset is unknown to Python.
return unicode(rawval, fallback_charset, errors)
else:
return unquote(value)