r"""

\A( # start of string and capture group

(?:W/)? # optional weak indicator

" # opening quote

[^"]* # any sequence of non-quote characters

" # end quote

)\Z # end of string and capture group

""",

re.X,

"""

A version of Python's urllib.parse.urlencode() function that can operate on

MultiValueDict and non-string values.

"""

if isinstance(query, MultiValueDict):

query = query.lists()

elif hasattr(query, "items"):

query = query.items()

query_params = []

for key, value in query:

if value is None:

raise TypeError(

"Cannot encode None for key '%s' in a query string. Did you "

"mean to pass an empty string or omit the value?" % key

)

elif not doseq or isinstance(value, (str, bytes)):

query_val = value

else:

try:

itr = iter(value)

except TypeError:

query_val = value

else:

# Consume generators and iterators, when doseq=True, to

# work around https://bugs.python.org/issue31706.

query_val = []

for item in itr:

if item is None:

raise TypeError(

"Cannot encode None for key '%s' in a query "

"string. Did you mean to pass an empty string or "

"omit the value?" % key

)

elif not isinstance(item, bytes):

item = str(item)

query_val.append(item)

query_params.append((key, query_val))

"""

Format the time to match the RFC 5322 date format as specified by RFC 9110

Section 5.6.7.

`epoch_seconds` is a floating point number expressed in seconds since the

epoch, in UTC - such as that outputted by time.time(). If set to None, it

defaults to the current time.

Output a string in the format 'Wdy, DD Mon YYYY HH:MM:SS GMT'.

"""

"""

Parse a date format as specified by HTTP RFC 9110 Section 5.6.7.

The three formats allowed by the RFC are accepted, even if only the first

one is still in widespread use.

Return an integer expressed in seconds since the epoch, in UTC.

"""

# email.utils.parsedate() does the job for RFC 1123 dates; unfortunately

# RFC 9110 makes it mandatory to support RFC 850 dates too. So we roll

# our own RFC-compliant parsing.

for regex in RFC1123_DATE, RFC850_DATE, ASCTIME_DATE:

m = regex.match(date)

if m is not None:

break

else:

raise ValueError("%r is not in a valid HTTP date format" % date)

try:

year = int(m["year"])

if year < 100:

current_year = datetime.now(tz=timezone.utc).year

current_century = current_year - (current_year % 100)

if year - (current_year % 100) > 50:

# year that appears to be more than 50 years in the future are

# interpreted as representing the past.

year += current_century - 100

else:

year += current_century

month = MONTHS.index(m["mon"].lower()) + 1

day = int(m["day"])

hour = int(m["hour"])

min = int(m["min"])

sec = int(m["sec"])

result = datetime(year, month, day, hour, min, sec, tzinfo=timezone.utc)

return int(result.timestamp())

except Exception as exc:

"""

Same as parse_http_date, but return None if the input is invalid.

"""

try:

return parse_http_date(date)

except Exception:

"""

Convert a base 36 string to an int. Raise ValueError if the input won't fit

into an int.

"""

# To prevent overconsumption of server resources, reject any

# base36 string that is longer than 13 base36 digits (13 digits

# is sufficient to base36-encode any 64-bit integer)

if len(s) > 13:

raise ValueError("Base36 input too large")

"""Convert an integer to a base36 string."""

char_set = "0123456789abcdefghijklmnopqrstuvwxyz"

if i < 0:

raise ValueError("Negative base36 conversion input.")

if i < 36:

return char_set[i]

b36 = ""

while i != 0:

i, n = divmod(i, 36)

b36 = char_set[n] + b36

"""

Encode a bytestring to a base64 string for use in URLs. Strip any trailing

equal signs.

"""

"""

Decode a base64 encoded string. Add back any trailing equal signs that

might have been stripped.

"""

s = s.encode()

try:

return base64.urlsafe_b64decode(s.ljust(len(s) + len(s) % 4, b"="))

except (LookupError, BinasciiError) as e:

"""

Parse a string of ETags given in an If-None-Match or If-Match header as

defined by RFC 9110. Return a list of quoted ETags, or ['*'] if all ETags

should be matched.

"""

if etag_str.strip() == "*":

return ["*"]

else:

# Parse each ETag individually, and return any that are valid.

etag_matches = (ETAG_MATCH.match(etag.strip()) for etag in etag_str.split(","))

"""

If the provided string is already a quoted ETag, return it. Otherwise, wrap

the string in quotes, making it a strong ETag.

"""

if ETAG_MATCH.match(etag_str):

return etag_str

else:

"""

Return ``True`` if the host is either an exact match or a match

to the wildcard pattern.

Any pattern beginning with a period matches a domain and all of its

subdomains. (e.g. ``.example.com`` matches ``example.com`` and

``foo.example.com``). Anything else is an exact string match.

"""

if not pattern:

return False

pattern = pattern.lower()

return (

pattern[0] == "."

and (host.endswith(pattern) or host == pattern[1:])

or pattern == host

"""

Return ``True`` if the url uses an allowed host and a safe scheme.

Always return ``False`` on an empty url.

If ``require_https`` is ``True``, only 'https' will be considered a valid

scheme, as opposed to 'http' and 'https' with the default, ``False``.

Note: "True" doesn't entail that a URL is "safe". It may still be e.g.

quoted incorrectly. Ensure to also use django.utils.encoding.iri_to_uri()

on the path component of untrusted URLs.

"""

if url is not None:

url = url.strip()

if not url:

return False

if allowed_hosts is None:

allowed_hosts = set()

elif isinstance(allowed_hosts, str):

allowed_hosts = {allowed_hosts}

# Chrome treats \ completely as / in paths but it could be part of some

# basic auth credentials so we need to check both URLs.

return _url_has_allowed_host_and_scheme(

url, allowed_hosts, require_https=require_https

) and _url_has_allowed_host_and_scheme(

url.replace("\\", "/"), allowed_hosts, require_https=require_https

# Chrome considers any URL with more than two slashes to be absolute, but

# urlsplit is not so flexible. Treat any url with three slashes as unsafe.

if url.startswith("///"):

return False

try:

url_info = urlsplit(url)

except ValueError: # e.g. invalid IPv6 addresses

return False

# Forbid URLs like http:///example.com - with a scheme, but without a hostname.

# In that URL, example.com is not the hostname but, a path component. However,

# Chrome will still consider example.com to be the hostname, so we must not

# allow this syntax.

if not url_info.netloc and url_info.scheme:

return False

# Forbid URLs that start with control characters. Some browsers (like

# Chrome) ignore quite a few control characters at the start of a

# URL and might consider the URL as scheme relative.

if unicodedata.category(url[0])[0] == "C":

return False

scheme = url_info.scheme

# Consider URLs without a scheme (e.g. //example.com/p) to be http.

if not url_info.scheme and url_info.netloc:

scheme = "http"

valid_schemes = ["https"] if require_https else ["http", "https"]

return (not url_info.netloc or url_info.netloc in allowed_hosts) and (

not scheme or scheme in valid_schemes

"""

If redirecting to an absolute path (two leading slashes), a slash must be

escaped to prevent browsers from handling the path as schemaless and

redirecting to another host.

"""

if url.startswith("//"):

url = "/%2F{}".format(url.removeprefix("//"))

while s[:1] == ";":

s = s[1:]

end = s.find(";")

while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2:

end = s.find(";", end + 1)

if end < 0:

end = len(s)

f = s[:end]

yield f.strip()

"""

Parse a Content-type like header.

Return the main content-type and a dictionary of options.

"""

parts = _parseparam(";" + line)

key = parts.__next__().lower()

pdict = {}

for p in parts:

i = p.find("=")

if i >= 0:

has_encoding = False

name = p[:i].strip().lower()

if name.endswith("*"):

# Lang/encoding embedded in the value (like "filename*=UTF-8''file.ext")

# https://tools.ietf.org/html/rfc2231#section-4

name = name[:-1]

if p.count("'") == 2:

has_encoding = True

value = p[i + 1 :].strip()

if len(value) >= 2 and value[0] == value[-1] == '"':

value = value[1:-1]

value = value.replace("\\\\", "\\").replace('\\"', '"')

if has_encoding:

encoding, lang, value = value.split("'")

value = unquote(value, encoding=encoding)

pdict[name] = value

"""

Construct a Content-Disposition HTTP header value from the given filename

as specified by RFC 6266.

"""

if filename:

disposition = "attachment" if as_attachment else "inline"

try:

filename.encode("ascii")

file_expr = 'filename="{}"'.format(

filename.replace("\\", "\\\\").replace('"', r"\"")

)

except UnicodeEncodeError:

file_expr = "filename*=utf-8''{}".format(quote(filename))

return f"{disposition}; {file_expr}"

elif as_attachment:

return "attachment"

else: