403 lines
14 KiB
Python
403 lines
14 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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import unicodedata
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import warnings
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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.core.exceptions import TooManyFieldsSent
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from django.utils import six
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from django.utils.datastructures import MultiValueDict
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from django.utils.deprecation import RemovedInDjango21Warning
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from django.utils.encoding import force_bytes, force_str, force_text
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from django.utils.functional import keep_lazy_text
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from django.utils.six.moves.urllib.parse import (
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quote, quote_plus, unquote, unquote_plus, urlencode as original_urlencode,
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urlparse,
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)
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# based on RFC 7232, Appendix C
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ETAG_MATCH = re.compile(r'''
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\A( # start of string and capture group
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(?:W/)? # optional weak indicator
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" # opening quote
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[^"]* # any sequence of non-quote characters
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" # end quote
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)\Z # end of string and capture group
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''', re.X)
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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$' % (__M, __D2, __T, __Y))
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RFC3986_GENDELIMS = str(":/?#[]@")
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RFC3986_SUBDELIMS = str("!$&'()*+,;=")
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FIELDS_MATCH = re.compile('[&;]')
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@keep_lazy_text
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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(quote(force_str(url), force_str(safe)))
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@keep_lazy_text
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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(quote_plus(force_str(url), force_str(safe)))
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@keep_lazy_text
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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(unquote(force_str(quoted_url)))
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@keep_lazy_text
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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(unquote_plus(force_str(quoted_url)))
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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 original_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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RFC7231 section 7.1.1.1.
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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 RFC7231 section 7.1.1.1.
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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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# RFC7231 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 six.PY2 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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char_set = '0123456789abcdefghijklmnopqrstuvwxyz'
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if i < 0:
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raise ValueError("Negative base36 conversion input.")
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if six.PY2:
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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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if i < 36:
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return char_set[i]
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b36 = ''
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while i != 0:
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i, n = divmod(i, 36)
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b36 = char_set[n] + b36
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return b36
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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 = force_bytes(s)
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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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Parse a string of ETags given in an If-None-Match or If-Match header as
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defined by RFC 7232. Return a list of quoted ETags, or ['*'] if all ETags
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should be matched.
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"""
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if etag_str.strip() == '*':
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return ['*']
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else:
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# Parse each ETag individually, and return any that are valid.
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etag_matches = (ETAG_MATCH.match(etag.strip()) for etag in etag_str.split(','))
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return [match.group(1) for match in etag_matches if match]
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def quote_etag(etag_str):
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"""
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If the provided string is already a quoted ETag, return it. Otherwise, wrap
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the string in quotes, making it a strong ETag.
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"""
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if ETAG_MATCH.match(etag_str):
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return etag_str
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else:
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return '"%s"' % etag_str
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def is_same_domain(host, pattern):
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"""
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Return ``True`` if the host is either an exact match or a match
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to the wildcard pattern.
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Any pattern beginning with a period matches a domain and all of its
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subdomains. (e.g. ``.example.com`` matches ``example.com`` and
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``foo.example.com``). Anything else is an exact string match.
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"""
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if not pattern:
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return False
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pattern = pattern.lower()
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return (
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pattern[0] == '.' and (host.endswith(pattern) or host == pattern[1:]) or
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pattern == host
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)
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def is_safe_url(url, host=None, allowed_hosts=None, require_https=False):
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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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If ``require_https`` is ``True``, only 'https' will be considered a valid
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scheme, as opposed to 'http' and 'https' with the default, ``False``.
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"""
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if url is not None:
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url = url.strip()
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if not url:
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return False
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if six.PY2:
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try:
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url = force_text(url)
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except UnicodeDecodeError:
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return False
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if allowed_hosts is None:
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allowed_hosts = set()
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if host:
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warnings.warn(
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"The host argument is deprecated, use allowed_hosts instead.",
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RemovedInDjango21Warning,
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stacklevel=2,
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)
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# Avoid mutating the passed in allowed_hosts.
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allowed_hosts = allowed_hosts | {host}
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# Chrome treats \ completely as / in paths but it could be part of some
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# basic auth credentials so we need to check both URLs.
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return (_is_safe_url(url, allowed_hosts, require_https=require_https) and
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_is_safe_url(url.replace('\\', '/'), allowed_hosts, require_https=require_https))
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def _is_safe_url(url, allowed_hosts, require_https=False):
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# Chrome considers any URL with more than two slashes to be absolute, but
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# urlparse is not so flexible. Treat any url with three slashes as unsafe.
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if url.startswith('///'):
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return False
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url_info = urlparse(url)
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# Forbid URLs like http:///example.com - with a scheme, but without a hostname.
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# In that URL, example.com is not the hostname but, a path component. However,
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# Chrome will still consider example.com to be the hostname, so we must not
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# allow this syntax.
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if not url_info.netloc and url_info.scheme:
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return False
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# Forbid URLs that start with control characters. Some browsers (like
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# Chrome) ignore quite a few control characters at the start of a
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# URL and might consider the URL as scheme relative.
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if unicodedata.category(url[0])[0] == 'C':
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return False
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scheme = url_info.scheme
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# Consider URLs without a scheme (e.g. //example.com/p) to be http.
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if not url_info.scheme and url_info.netloc:
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scheme = 'http'
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valid_schemes = ['https'] if require_https else ['http', 'https']
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return ((not url_info.netloc or url_info.netloc in allowed_hosts) and
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(not scheme or scheme in valid_schemes))
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def limited_parse_qsl(qs, keep_blank_values=False, encoding='utf-8',
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errors='replace', fields_limit=None):
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"""
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Return a list of key/value tuples parsed from query string.
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Copied from urlparse with an additional "fields_limit" argument.
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Copyright (C) 2013 Python Software Foundation (see LICENSE.python).
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Arguments:
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qs: percent-encoded query string to be parsed
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keep_blank_values: flag indicating whether blank values in
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percent-encoded queries should be treated as blank strings. A
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true value indicates that blanks should be retained as blank
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strings. The default false value indicates that blank values
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are to be ignored and treated as if they were not included.
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encoding and errors: specify how to decode percent-encoded sequences
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into Unicode characters, as accepted by the bytes.decode() method.
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fields_limit: maximum number of fields parsed or an exception
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is raised. None means no limit and is the default.
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"""
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if fields_limit:
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pairs = FIELDS_MATCH.split(qs, fields_limit)
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if len(pairs) > fields_limit:
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raise TooManyFieldsSent(
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'The number of GET/POST parameters exceeded '
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'settings.DATA_UPLOAD_MAX_NUMBER_FIELDS.'
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)
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else:
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pairs = FIELDS_MATCH.split(qs)
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r = []
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for name_value in pairs:
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if not name_value:
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continue
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nv = name_value.split(str('='), 1)
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if len(nv) != 2:
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# Handle case of a control-name with no equal sign
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if keep_blank_values:
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nv.append('')
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else:
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continue
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if len(nv[1]) or keep_blank_values:
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if six.PY3:
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name = nv[0].replace('+', ' ')
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name = unquote(name, encoding=encoding, errors=errors)
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value = nv[1].replace('+', ' ')
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value = unquote(value, encoding=encoding, errors=errors)
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else:
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name = unquote(nv[0].replace(b'+', b' '))
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value = unquote(nv[1].replace(b'+', b' '))
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r.append((name, value))
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return r
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