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66a65ba43c
For me as a non native English speaker, the sentence with its embedded clause was very hard to understand. modified: Lib/email/utils.py Automerge-Triggered-By: @csabella
369 lines
13 KiB
Python
369 lines
13 KiB
Python
# Copyright (C) 2001-2010 Python Software Foundation
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# Author: Barry Warsaw
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# Contact: email-sig@python.org
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"""Miscellaneous utilities."""
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__all__ = [
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'collapse_rfc2231_value',
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'decode_params',
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'decode_rfc2231',
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'encode_rfc2231',
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'formataddr',
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'formatdate',
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'format_datetime',
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'getaddresses',
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'make_msgid',
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'mktime_tz',
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'parseaddr',
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'parsedate',
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'parsedate_tz',
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'parsedate_to_datetime',
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'unquote',
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]
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import os
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import re
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import time
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import random
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import socket
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import datetime
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import urllib.parse
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from email._parseaddr import quote
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from email._parseaddr import AddressList as _AddressList
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from email._parseaddr import mktime_tz
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from email._parseaddr import parsedate, parsedate_tz, _parsedate_tz
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# Intrapackage imports
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from email.charset import Charset
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COMMASPACE = ', '
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EMPTYSTRING = ''
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UEMPTYSTRING = ''
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CRLF = '\r\n'
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TICK = "'"
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specialsre = re.compile(r'[][\\()<>@,:;".]')
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escapesre = re.compile(r'[\\"]')
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def _has_surrogates(s):
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"""Return True if s contains surrogate-escaped binary data."""
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# This check is based on the fact that unless there are surrogates, utf8
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# (Python's default encoding) can encode any string. This is the fastest
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# way to check for surrogates, see issue 11454 for timings.
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try:
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s.encode()
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return False
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except UnicodeEncodeError:
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return True
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# How to deal with a string containing bytes before handing it to the
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# application through the 'normal' interface.
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def _sanitize(string):
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# Turn any escaped bytes into unicode 'unknown' char. If the escaped
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# bytes happen to be utf-8 they will instead get decoded, even if they
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# were invalid in the charset the source was supposed to be in. This
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# seems like it is not a bad thing; a defect was still registered.
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original_bytes = string.encode('utf-8', 'surrogateescape')
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return original_bytes.decode('utf-8', 'replace')
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# Helpers
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def formataddr(pair, charset='utf-8'):
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"""The inverse of parseaddr(), this takes a 2-tuple of the form
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(realname, email_address) and returns the string value suitable
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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
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returned unmodified.
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The optional charset is the character set that is used to encode
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realname in case realname is not ASCII safe. Can be an instance of str or
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a Charset-like object which has a header_encode method. Default is
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'utf-8'.
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"""
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name, address = pair
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# The address MUST (per RFC) be ascii, so raise a UnicodeError if it isn't.
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address.encode('ascii')
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if name:
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try:
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name.encode('ascii')
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except UnicodeEncodeError:
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if isinstance(charset, str):
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charset = Charset(charset)
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encoded_name = charset.header_encode(name)
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return "%s <%s>" % (encoded_name, address)
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else:
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quotes = ''
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if specialsre.search(name):
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quotes = '"'
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name = escapesre.sub(r'\\\g<0>', name)
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return '%s%s%s <%s>' % (quotes, name, quotes, address)
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return address
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def getaddresses(fieldvalues):
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"""Return a list of (REALNAME, EMAIL) for each fieldvalue."""
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all = COMMASPACE.join(fieldvalues)
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a = _AddressList(all)
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return a.addresslist
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def _format_timetuple_and_zone(timetuple, zone):
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return '%s, %02d %s %04d %02d:%02d:%02d %s' % (
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['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'][timetuple[6]],
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timetuple[2],
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['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
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'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'][timetuple[1] - 1],
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timetuple[0], timetuple[3], timetuple[4], timetuple[5],
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zone)
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def formatdate(timeval=None, localtime=False, usegmt=False):
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"""Returns a date string as specified by RFC 2822, e.g.:
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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
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gmtime() and localtime(), otherwise the current time is used.
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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
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taking daylight savings time into account.
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Optional argument usegmt means that the timezone is written out as
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an ascii string, not numeric one (so "GMT" instead of "+0000"). This
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is needed for HTTP, and is only used when localtime==False.
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"""
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# Note: we cannot use strftime() because that honors the locale and RFC
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# 2822 requires that day and month names be the English abbreviations.
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if timeval is None:
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timeval = time.time()
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if localtime or usegmt:
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dt = datetime.datetime.fromtimestamp(timeval, datetime.timezone.utc)
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else:
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dt = datetime.datetime.utcfromtimestamp(timeval)
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if localtime:
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dt = dt.astimezone()
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usegmt = False
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return format_datetime(dt, usegmt)
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def format_datetime(dt, usegmt=False):
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"""Turn a datetime into a date string as specified in RFC 2822.
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If usegmt is True, dt must be an aware datetime with an offset of zero. In
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this case 'GMT' will be rendered instead of the normal +0000 required by
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RFC2822. This is to support HTTP headers involving date stamps.
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"""
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now = dt.timetuple()
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if usegmt:
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if dt.tzinfo is None or dt.tzinfo != datetime.timezone.utc:
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raise ValueError("usegmt option requires a UTC datetime")
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zone = 'GMT'
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elif dt.tzinfo is None:
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zone = '-0000'
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else:
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zone = dt.strftime("%z")
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return _format_timetuple_and_zone(now, zone)
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def make_msgid(idstring=None, domain=None):
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"""Returns a string suitable for RFC 2822 compliant Message-ID, e.g:
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<142480216486.20800.16526388040877946887@nightshade.la.mastaler.com>
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Optional idstring if given is a string used to strengthen the
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uniqueness of the message id. Optional domain if given provides the
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portion of the message id after the '@'. It defaults to the locally
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defined hostname.
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"""
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timeval = int(time.time()*100)
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pid = os.getpid()
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randint = random.getrandbits(64)
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if idstring is None:
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idstring = ''
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else:
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idstring = '.' + idstring
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if domain is None:
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domain = socket.getfqdn()
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msgid = '<%d.%d.%d%s@%s>' % (timeval, pid, randint, idstring, domain)
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return msgid
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def parsedate_to_datetime(data):
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*dtuple, tz = _parsedate_tz(data)
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if tz is None:
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return datetime.datetime(*dtuple[:6])
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return datetime.datetime(*dtuple[:6],
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tzinfo=datetime.timezone(datetime.timedelta(seconds=tz)))
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def parseaddr(addr):
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"""
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Parse addr into its constituent realname and email address parts.
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Return a tuple of realname and email address, unless the parse fails, in
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which case return a 2-tuple of ('', '').
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"""
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addrs = _AddressList(addr).addresslist
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if not addrs:
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return '', ''
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return addrs[0]
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# rfc822.unquote() doesn't properly de-backslash-ify in Python pre-2.3.
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def unquote(str):
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"""Remove quotes from a string."""
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if len(str) > 1:
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if str.startswith('"') and str.endswith('"'):
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return str[1:-1].replace('\\\\', '\\').replace('\\"', '"')
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if str.startswith('<') and str.endswith('>'):
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return str[1:-1]
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return str
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# RFC2231-related functions - parameter encoding and decoding
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def decode_rfc2231(s):
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"""Decode string according to RFC 2231"""
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parts = s.split(TICK, 2)
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if len(parts) <= 2:
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return None, None, s
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return parts
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def encode_rfc2231(s, charset=None, language=None):
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"""Encode string according to RFC 2231.
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If neither charset nor language is given, then s is returned as-is. If
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charset is given but not language, the string is encoded using the empty
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string for language.
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"""
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s = urllib.parse.quote(s, safe='', encoding=charset or 'ascii')
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if charset is None and language is None:
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return s
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if language is None:
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language = ''
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return "%s'%s'%s" % (charset, language, s)
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rfc2231_continuation = re.compile(r'^(?P<name>\w+)\*((?P<num>[0-9]+)\*?)?$',
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re.ASCII)
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def decode_params(params):
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"""Decode parameters list according to RFC 2231.
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params is a sequence of 2-tuples containing (param name, string value).
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"""
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new_params = [params[0]]
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# Map parameter's name to a list of continuations. The values are a
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# 3-tuple of the continuation number, the string value, and a flag
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# specifying whether a particular segment is %-encoded.
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rfc2231_params = {}
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for name, value in params[1:]:
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encoded = name.endswith('*')
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value = unquote(value)
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mo = rfc2231_continuation.match(name)
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if mo:
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name, num = mo.group('name', 'num')
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if num is not None:
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num = int(num)
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rfc2231_params.setdefault(name, []).append((num, value, encoded))
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else:
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new_params.append((name, '"%s"' % quote(value)))
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if rfc2231_params:
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for name, continuations in rfc2231_params.items():
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value = []
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extended = False
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# Sort by number
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continuations.sort()
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# And now append all values in numerical order, converting
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# %-encodings for the encoded segments. If any of the
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# continuation names ends in a *, then the entire string, after
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# decoding segments and concatenating, must have the charset and
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# language specifiers at the beginning of the string.
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for num, s, encoded in continuations:
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if encoded:
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# Decode as "latin-1", so the characters in s directly
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# represent the percent-encoded octet values.
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# collapse_rfc2231_value treats this as an octet sequence.
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s = urllib.parse.unquote(s, encoding="latin-1")
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extended = True
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value.append(s)
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value = quote(EMPTYSTRING.join(value))
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if extended:
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charset, language, value = decode_rfc2231(value)
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new_params.append((name, (charset, language, '"%s"' % value)))
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else:
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new_params.append((name, '"%s"' % value))
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return new_params
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def collapse_rfc2231_value(value, errors='replace',
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fallback_charset='us-ascii'):
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if not isinstance(value, tuple) or len(value) != 3:
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return unquote(value)
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# While value comes to us as a unicode string, we need it to be a bytes
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# object. We do not want bytes() normal utf-8 decoder, we want a straight
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# interpretation of the string as character bytes.
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charset, language, text = value
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if charset is None:
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# Issue 17369: if charset/lang is None, decode_rfc2231 couldn't parse
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# the value, so use the fallback_charset.
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charset = fallback_charset
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rawbytes = bytes(text, 'raw-unicode-escape')
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try:
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return str(rawbytes, charset, errors)
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except LookupError:
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# charset is not a known codec.
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return unquote(text)
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#
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# datetime doesn't provide a localtime function yet, so provide one. Code
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# adapted from the patch in issue 9527. This may not be perfect, but it is
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# better than not having it.
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#
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def localtime(dt=None, isdst=-1):
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"""Return local time as an aware datetime object.
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If called without arguments, return current time. Otherwise *dt*
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argument should be a datetime instance, and it is converted to the
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local time zone according to the system time zone database. If *dt* is
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naive (that is, dt.tzinfo is None), it is assumed to be in local time.
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In this case, a positive or zero value for *isdst* causes localtime to
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presume initially that summer time (for example, Daylight Saving Time)
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is or is not (respectively) in effect for the specified time. A
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negative value for *isdst* causes the localtime() function to attempt
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to divine whether summer time is in effect for the specified time.
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"""
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if dt is None:
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return datetime.datetime.now(datetime.timezone.utc).astimezone()
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if dt.tzinfo is not None:
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return dt.astimezone()
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# We have a naive datetime. Convert to a (localtime) timetuple and pass to
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# system mktime together with the isdst hint. System mktime will return
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# seconds since epoch.
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tm = dt.timetuple()[:-1] + (isdst,)
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seconds = time.mktime(tm)
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localtm = time.localtime(seconds)
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try:
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delta = datetime.timedelta(seconds=localtm.tm_gmtoff)
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tz = datetime.timezone(delta, localtm.tm_zone)
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except AttributeError:
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# Compute UTC offset and compare with the value implied by tm_isdst.
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# If the values match, use the zone name implied by tm_isdst.
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delta = dt - datetime.datetime(*time.gmtime(seconds)[:6])
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dst = time.daylight and localtm.tm_isdst > 0
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gmtoff = -(time.altzone if dst else time.timezone)
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if delta == datetime.timedelta(seconds=gmtoff):
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tz = datetime.timezone(delta, time.tzname[dst])
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else:
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tz = datetime.timezone(delta)
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return dt.replace(tzinfo=tz)
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