264 lines
8.9 KiB
Python
264 lines
8.9 KiB
Python
from __future__ import unicode_literals
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import base64
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import calendar
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import datetime
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import re
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import sys
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try:
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from urllib import parse as urllib_parse
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except ImportError: # Python 2
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import urllib as urllib_parse
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import urlparse
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urllib_parse.urlparse = urlparse.urlparse
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from binascii import Error as BinasciiError
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from email.utils import formatdate
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from django.utils.datastructures import MultiValueDict
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from django.utils.encoding import force_str, force_text
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from django.utils.functional import allow_lazy
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from django.utils import six
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ETAG_MATCH = re.compile(r'(?:W/)?"((?:\\.|[^"])*)"')
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MONTHS = 'jan feb mar apr may jun jul aug sep oct nov dec'.split()
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__D = r'(?P<day>\d{2})'
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__D2 = r'(?P<day>[ \d]\d)'
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__M = r'(?P<mon>\w{3})'
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__Y = r'(?P<year>\d{4})'
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__Y2 = r'(?P<year>\d{2})'
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__T = r'(?P<hour>\d{2}):(?P<min>\d{2}):(?P<sec>\d{2})'
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RFC1123_DATE = re.compile(r'^\w{3}, %s %s %s %s GMT$' % (__D, __M, __Y, __T))
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RFC850_DATE = re.compile(r'^\w{6,9}, %s-%s-%s %s GMT$' % (__D, __M, __Y2, __T))
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ASCTIME_DATE = re.compile(r'^\w{3} %s %s %s %s$' % (__M, __D2, __T, __Y))
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def urlquote(url, safe='/'):
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"""
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A version of Python's urllib.quote() function that can operate on unicode
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strings. The url is first UTF-8 encoded before quoting. The returned string
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can safely be used as part of an argument to a subsequent iri_to_uri() call
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without double-quoting occurring.
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"""
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return force_text(urllib_parse.quote(force_str(url), force_str(safe)))
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urlquote = allow_lazy(urlquote, six.text_type)
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def urlquote_plus(url, safe=''):
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"""
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A version of Python's urllib.quote_plus() function that can operate on
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unicode strings. The url is first UTF-8 encoded before quoting. The
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returned string can safely be used as part of an argument to a subsequent
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iri_to_uri() call without double-quoting occurring.
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"""
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return force_text(urllib_parse.quote_plus(force_str(url), force_str(safe)))
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urlquote_plus = allow_lazy(urlquote_plus, six.text_type)
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def urlunquote(quoted_url):
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"""
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A wrapper for Python's urllib.unquote() function that can operate on
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the result of django.utils.http.urlquote().
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"""
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return force_text(urllib_parse.unquote(force_str(quoted_url)))
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urlunquote = allow_lazy(urlunquote, six.text_type)
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def urlunquote_plus(quoted_url):
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"""
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A wrapper for Python's urllib.unquote_plus() function that can operate on
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the result of django.utils.http.urlquote_plus().
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"""
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return force_text(urllib_parse.unquote_plus(force_str(quoted_url)))
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urlunquote_plus = allow_lazy(urlunquote_plus, six.text_type)
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def urlencode(query, doseq=0):
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"""
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A version of Python's urllib.urlencode() function that can operate on
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unicode strings. The parameters are first cast to UTF-8 encoded strings and
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then encoded as per normal.
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"""
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if isinstance(query, MultiValueDict):
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query = query.lists()
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elif hasattr(query, 'items'):
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query = query.items()
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return urllib_parse.urlencode(
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[(force_str(k),
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[force_str(i) for i in v] if isinstance(v, (list,tuple)) else force_str(v))
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for k, v in query],
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doseq)
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def cookie_date(epoch_seconds=None):
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"""
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Formats the time to ensure compatibility with Netscape's cookie standard.
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Accepts a floating point number expressed in seconds since the epoch, in
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UTC - such as that outputted by time.time(). If set to None, defaults to
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the current time.
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Outputs a string in the format 'Wdy, DD-Mon-YYYY HH:MM:SS GMT'.
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"""
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rfcdate = formatdate(epoch_seconds)
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return '%s-%s-%s GMT' % (rfcdate[:7], rfcdate[8:11], rfcdate[12:25])
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def http_date(epoch_seconds=None):
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"""
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Formats the time to match the RFC1123 date format as specified by HTTP
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RFC2616 section 3.3.1.
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Accepts a floating point number expressed in seconds since the epoch, in
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UTC - such as that outputted by time.time(). If set to None, defaults to
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the current time.
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Outputs a string in the format 'Wdy, DD Mon YYYY HH:MM:SS GMT'.
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"""
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return formatdate(epoch_seconds, usegmt=True)
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def parse_http_date(date):
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"""
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Parses a date format as specified by HTTP RFC2616 section 3.3.1.
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The three formats allowed by the RFC are accepted, even if only the first
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one is still in widespread use.
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Returns an integer expressed in seconds since the epoch, in UTC.
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"""
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# emails.Util.parsedate does the job for RFC1123 dates; unfortunately
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# RFC2616 makes it mandatory to support RFC850 dates too. So we roll
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# our own RFC-compliant parsing.
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for regex in RFC1123_DATE, RFC850_DATE, ASCTIME_DATE:
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m = regex.match(date)
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if m is not None:
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break
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else:
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raise ValueError("%r is not in a valid HTTP date format" % date)
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try:
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year = int(m.group('year'))
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if year < 100:
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if year < 70:
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year += 2000
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else:
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year += 1900
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month = MONTHS.index(m.group('mon').lower()) + 1
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day = int(m.group('day'))
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hour = int(m.group('hour'))
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min = int(m.group('min'))
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sec = int(m.group('sec'))
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result = datetime.datetime(year, month, day, hour, min, sec)
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return calendar.timegm(result.utctimetuple())
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except Exception:
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six.reraise(ValueError, ValueError("%r is not a valid date" % date), sys.exc_info()[2])
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def parse_http_date_safe(date):
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"""
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Same as parse_http_date, but returns None if the input is invalid.
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"""
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try:
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return parse_http_date(date)
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except Exception:
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pass
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# Base 36 functions: useful for generating compact URLs
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def base36_to_int(s):
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"""
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Converts a base 36 string to an ``int``. Raises ``ValueError` if the
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input won't fit into an int.
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"""
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# To prevent overconsumption of server resources, reject any
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# base36 string that is long than 13 base36 digits (13 digits
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# is sufficient to base36-encode any 64-bit integer)
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if len(s) > 13:
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raise ValueError("Base36 input too large")
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value = int(s, 36)
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# ... then do a final check that the value will fit into an int to avoid
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# returning a long (#15067). The long type was removed in Python 3.
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if not six.PY3 and value > sys.maxint:
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raise ValueError("Base36 input too large")
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return value
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def int_to_base36(i):
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"""
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Converts an integer to a base36 string
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"""
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digits = "0123456789abcdefghijklmnopqrstuvwxyz"
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factor = 0
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if i < 0:
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raise ValueError("Negative base36 conversion input.")
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if not six.PY3:
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if not isinstance(i, six.integer_types):
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raise TypeError("Non-integer base36 conversion input.")
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if i > sys.maxint:
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raise ValueError("Base36 conversion input too large.")
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# Find starting factor
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while True:
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factor += 1
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if i < 36 ** factor:
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factor -= 1
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break
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base36 = []
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# Construct base36 representation
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while factor >= 0:
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j = 36 ** factor
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base36.append(digits[i // j])
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i = i % j
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factor -= 1
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return ''.join(base36)
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def urlsafe_base64_encode(s):
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"""
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Encodes a bytestring in base64 for use in URLs, stripping any trailing
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equal signs.
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"""
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return base64.urlsafe_b64encode(s).rstrip(b'\n=')
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def urlsafe_base64_decode(s):
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"""
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Decodes a base64 encoded string, adding back any trailing equal signs that
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might have been stripped.
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"""
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s = s.encode('utf-8') # base64encode should only return ASCII.
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try:
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return base64.urlsafe_b64decode(s.ljust(len(s) + len(s) % 4, b'='))
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except (LookupError, BinasciiError) as e:
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raise ValueError(e)
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def parse_etags(etag_str):
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"""
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Parses a string with one or several etags passed in If-None-Match and
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If-Match headers by the rules in RFC 2616. Returns a list of etags
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without surrounding double quotes (") and unescaped from \<CHAR>.
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"""
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etags = ETAG_MATCH.findall(etag_str)
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if not etags:
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# etag_str has wrong format, treat it as an opaque string then
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return [etag_str]
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etags = [e.encode('ascii').decode('unicode_escape') for e in etags]
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return etags
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def quote_etag(etag):
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"""
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Wraps a string in double quotes escaping contents as necessary.
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"""
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return '"%s"' % etag.replace('\\', '\\\\').replace('"', '\\"')
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def same_origin(url1, url2):
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"""
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Checks if two URLs are 'same-origin'
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"""
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p1, p2 = urllib_parse.urlparse(url1), urllib_parse.urlparse(url2)
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try:
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return (p1.scheme, p1.hostname, p1.port) == (p2.scheme, p2.hostname, p2.port)
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except ValueError:
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return False
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def is_safe_url(url, host=None):
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"""
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Return ``True`` if the url is a safe redirection (i.e. it doesn't point to
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a different host and uses a safe scheme).
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Always returns ``False`` on an empty url.
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"""
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if not url:
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return False
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url_info = urllib_parse.urlparse(url)
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return (not url_info.netloc or url_info.netloc == host) and \
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(not url_info.scheme or url_info.scheme in ['http', 'https'])
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