# -*- coding: utf-8 -*- """ werkzeug.http ~~~~~~~~~~~~~ Werkzeug comes with a bunch of utilities that help Werkzeug to deal with HTTP data. Most of the classes and functions provided by this module are used by the wrappers, but they are useful on their own, too, especially if the response and request objects are not used. This covers some of the more HTTP centric features of WSGI, some other utilities such as cookie handling are documented in the `werkzeug.utils` module. :copyright: 2007 Pallets :license: BSD-3-Clause """ import base64 import re import warnings from datetime import datetime from datetime import timedelta from hashlib import md5 from time import gmtime from time import time from ._compat import integer_types from ._compat import iteritems from ._compat import PY2 from ._compat import string_types from ._compat import text_type from ._compat import to_bytes from ._compat import to_unicode from ._compat import try_coerce_native from ._internal import _cookie_parse_impl from ._internal import _cookie_quote from ._internal import _make_cookie_domain try: from email.utils import parsedate_tz except ImportError: from email.Utils import parsedate_tz try: from urllib.request import parse_http_list as _parse_list_header from urllib.parse import unquote_to_bytes as _unquote except ImportError: from urllib2 import parse_http_list as _parse_list_header from urllib2 import unquote as _unquote _cookie_charset = "latin1" _basic_auth_charset = "utf-8" # for explanation of "media-range", etc. see Sections 5.3.{1,2} of RFC 7231 _accept_re = re.compile( r""" ( # media-range capturing-parenthesis [^\s;,]+ # type/subtype (?:[ \t]*;[ \t]* # ";" (?: # parameter non-capturing-parenthesis [^\s;,q][^\s;,]* # token that doesn't start with "q" | # or q[^\s;,=][^\s;,]* # token that is more than just "q" ) )* # zero or more parameters ) # end of media-range (?:[ \t]*;[ \t]*q= # weight is a "q" parameter (\d*(?:\.\d+)?) # qvalue capturing-parentheses [^,]* # "extension" accept params: who cares? )? # accept params are optional """, re.VERBOSE, ) _token_chars = frozenset( "!#$%&'*+-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ^_`abcdefghijklmnopqrstuvwxyz|~" ) _etag_re = re.compile(r'([Ww]/)?(?:"(.*?)"|(.*?))(?:\s*,\s*|$)') _unsafe_header_chars = set('()<>@,;:"/[]?={} \t') _option_header_piece_re = re.compile( r""" ;\s*,?\s* # newlines were replaced with commas (?P<key> "[^"\\]*(?:\\.[^"\\]*)*" # quoted string | [^\s;,=*]+ # token ) (?:\*(?P<count>\d+))? # *1, optional continuation index \s* (?: # optionally followed by =value (?: # equals sign, possibly with encoding \*\s*=\s* # * indicates extended notation (?: # optional encoding (?P<encoding>[^\s]+?) '(?P<language>[^\s]*?)' )? | =\s* # basic notation ) (?P<value> "[^"\\]*(?:\\.[^"\\]*)*" # quoted string | [^;,]+ # token )? )? \s* """, flags=re.VERBOSE, ) _option_header_start_mime_type = re.compile(r",\s*([^;,\s]+)([;,]\s*.+)?") _entity_headers = frozenset( [ "allow", "content-encoding", "content-language", "content-length", "content-location", "content-md5", "content-range", "content-type", "expires", "last-modified", ] ) _hop_by_hop_headers = frozenset( [ "connection", "keep-alive", "proxy-authenticate", "proxy-authorization", "te", "trailer", "transfer-encoding", "upgrade", ] ) HTTP_STATUS_CODES = { 100: "Continue", 101: "Switching Protocols", 102: "Processing", 200: "OK", 201: "Created", 202: "Accepted", 203: "Non Authoritative Information", 204: "No Content", 205: "Reset Content", 206: "Partial Content", 207: "Multi Status", 226: "IM Used", # see RFC 3229 300: "Multiple Choices", 301: "Moved Permanently", 302: "Found", 303: "See Other", 304: "Not Modified", 305: "Use Proxy", 307: "Temporary Redirect", 308: "Permanent Redirect", 400: "Bad Request", 401: "Unauthorized", 402: "Payment Required", # unused 403: "Forbidden", 404: "Not Found", 405: "Method Not Allowed", 406: "Not Acceptable", 407: "Proxy Authentication Required", 408: "Request Timeout", 409: "Conflict", 410: "Gone", 411: "Length Required", 412: "Precondition Failed", 413: "Request Entity Too Large", 414: "Request URI Too Long", 415: "Unsupported Media Type", 416: "Requested Range Not Satisfiable", 417: "Expectation Failed", 418: "I'm a teapot", # see RFC 2324 421: "Misdirected Request", # see RFC 7540 422: "Unprocessable Entity", 423: "Locked", 424: "Failed Dependency", 426: "Upgrade Required", 428: "Precondition Required", # see RFC 6585 429: "Too Many Requests", 431: "Request Header Fields Too Large", 449: "Retry With", # proprietary MS extension 451: "Unavailable For Legal Reasons", 500: "Internal Server Error", 501: "Not Implemented", 502: "Bad Gateway", 503: "Service Unavailable", 504: "Gateway Timeout", 505: "HTTP Version Not Supported", 507: "Insufficient Storage", 510: "Not Extended", } def wsgi_to_bytes(data): """coerce wsgi unicode represented bytes to real ones""" if isinstance(data, bytes): return data return data.encode("latin1") # XXX: utf8 fallback? def bytes_to_wsgi(data): assert isinstance(data, bytes), "data must be bytes" if isinstance(data, str): return data else: return data.decode("latin1") def quote_header_value(value, extra_chars="", allow_token=True): """Quote a header value if necessary. .. versionadded:: 0.5 :param value: the value to quote. :param extra_chars: a list of extra characters to skip quoting. :param allow_token: if this is enabled token values are returned unchanged. """ if isinstance(value, bytes): value = bytes_to_wsgi(value) value = str(value) if allow_token: token_chars = _token_chars | set(extra_chars) if set(value).issubset(token_chars): return value return '"%s"' % value.replace("\\", "\\\\").replace('"', '\\"') def unquote_header_value(value, is_filename=False): r"""Unquotes a header value. (Reversal of :func:`quote_header_value`). This does not use the real unquoting but what browsers are actually using for quoting. .. versionadded:: 0.5 :param value: the header value to unquote. """ if value and value[0] == value[-1] == '"': # this is not the real unquoting, but fixing this so that the # RFC is met will result in bugs with internet explorer and # probably some other browsers as well. IE for example is # uploading files with "C:\foo\bar.txt" as filename value = value[1:-1] # if this is a filename and the starting characters look like # a UNC path, then just return the value without quotes. Using the # replace sequence below on a UNC path has the effect of turning # the leading double slash into a single slash and then # _fix_ie_filename() doesn't work correctly. See #458. if not is_filename or value[:2] != "\\\\": return value.replace("\\\\", "\\").replace('\\"', '"') return value def dump_options_header(header, options): """The reverse function to :func:`parse_options_header`. :param header: the header to dump :param options: a dict of options to append. """ segments = [] if header is not None: segments.append(header) for key, value in iteritems(options): if value is None: segments.append(key) else: segments.append("%s=%s" % (key, quote_header_value(value))) return "; ".join(segments) def dump_header(iterable, allow_token=True): """Dump an HTTP header again. This is the reversal of :func:`parse_list_header`, :func:`parse_set_header` and :func:`parse_dict_header`. This also quotes strings that include an equals sign unless you pass it as dict of key, value pairs. >>> dump_header({'foo': 'bar baz'}) 'foo="bar baz"' >>> dump_header(('foo', 'bar baz')) 'foo, "bar baz"' :param iterable: the iterable or dict of values to quote. :param allow_token: if set to `False` tokens as values are disallowed. See :func:`quote_header_value` for more details. """ if isinstance(iterable, dict): items = [] for key, value in iteritems(iterable): if value is None: items.append(key) else: items.append( "%s=%s" % (key, quote_header_value(value, allow_token=allow_token)) ) else: items = [quote_header_value(x, allow_token=allow_token) for x in iterable] return ", ".join(items) def parse_list_header(value): """Parse lists as described by RFC 2068 Section 2. In particular, parse comma-separated lists where the elements of the list may include quoted-strings. A quoted-string could contain a comma. A non-quoted string could have quotes in the middle. Quotes are removed automatically after parsing. It basically works like :func:`parse_set_header` just that items may appear multiple times and case sensitivity is preserved. The return value is a standard :class:`list`: >>> parse_list_header('token, "quoted value"') ['token', 'quoted value'] To create a header from the :class:`list` again, use the :func:`dump_header` function. :param value: a string with a list header. :return: :class:`list` """ result = [] for item in _parse_list_header(value): if item[:1] == item[-1:] == '"': item = unquote_header_value(item[1:-1]) result.append(item) return result def parse_dict_header(value, cls=dict): """Parse lists of key, value pairs as described by RFC 2068 Section 2 and convert them into a python dict (or any other mapping object created from the type with a dict like interface provided by the `cls` argument): >>> d = parse_dict_header('foo="is a fish", bar="as well"') >>> type(d) is dict True >>> sorted(d.items()) [('bar', 'as well'), ('foo', 'is a fish')] If there is no value for a key it will be `None`: >>> parse_dict_header('key_without_value') {'key_without_value': None} To create a header from the :class:`dict` again, use the :func:`dump_header` function. .. versionchanged:: 0.9 Added support for `cls` argument. :param value: a string with a dict header. :param cls: callable to use for storage of parsed results. :return: an instance of `cls` """ result = cls() if not isinstance(value, text_type): # XXX: validate value = bytes_to_wsgi(value) for item in _parse_list_header(value): if "=" not in item: result[item] = None continue name, value = item.split("=", 1) if value[:1] == value[-1:] == '"': value = unquote_header_value(value[1:-1]) result[name] = value return result def parse_options_header(value, multiple=False): """Parse a ``Content-Type`` like header into a tuple with the content type and the options: >>> parse_options_header('text/html; charset=utf8') ('text/html', {'charset': 'utf8'}) This should not be used to parse ``Cache-Control`` like headers that use a slightly different format. For these headers use the :func:`parse_dict_header` function. .. versionchanged:: 0.15 :rfc:`2231` parameter continuations are handled. .. versionadded:: 0.5 :param value: the header to parse. :param multiple: Whether try to parse and return multiple MIME types :return: (mimetype, options) or (mimetype, options, mimetype, options, …) if multiple=True """ if not value: return "", {} result = [] value = "," + value.replace("\n", ",") while value: match = _option_header_start_mime_type.match(value) if not match: break result.append(match.group(1)) # mimetype options = {} # Parse options rest = match.group(2) continued_encoding = None while rest: optmatch = _option_header_piece_re.match(rest) if not optmatch: break option, count, encoding, language, option_value = optmatch.groups() # Continuations don't have to supply the encoding after the # first line. If we're in a continuation, track the current # encoding to use for subsequent lines. Reset it when the # continuation ends. if not count: continued_encoding = None else: if not encoding: encoding = continued_encoding continued_encoding = encoding option = unquote_header_value(option) if option_value is not None: option_value = unquote_header_value(option_value, option == "filename") if encoding is not None: option_value = _unquote(option_value).decode(encoding) if count: # Continuations append to the existing value. For # simplicity, this ignores the possibility of # out-of-order indices, which shouldn't happen anyway. options[option] = options.get(option, "") + option_value else: options[option] = option_value rest = rest[optmatch.end() :] result.append(options) if multiple is False: return tuple(result) value = rest return tuple(result) if result else ("", {}) def parse_accept_header(value, cls=None): """Parses an HTTP Accept-* header. This does not implement a complete valid algorithm but one that supports at least value and quality extraction. Returns a new :class:`Accept` object (basically a list of ``(value, quality)`` tuples sorted by the quality with some additional accessor methods). The second parameter can be a subclass of :class:`Accept` that is created with the parsed values and returned. :param value: the accept header string to be parsed. :param cls: the wrapper class for the return value (can be :class:`Accept` or a subclass thereof) :return: an instance of `cls`. """ if cls is None: cls = Accept if not value: return cls(None) result = [] for match in _accept_re.finditer(value): quality = match.group(2) if not quality: quality = 1 else: quality = max(min(float(quality), 1), 0) result.append((match.group(1), quality)) return cls(result) def parse_cache_control_header(value, on_update=None, cls=None): """Parse a cache control header. The RFC differs between response and request cache control, this method does not. It's your responsibility to not use the wrong control statements. .. versionadded:: 0.5 The `cls` was added. If not specified an immutable :class:`~werkzeug.datastructures.RequestCacheControl` is returned. :param value: a cache control header to be parsed. :param on_update: an optional callable that is called every time a value on the :class:`~werkzeug.datastructures.CacheControl` object is changed. :param cls: the class for the returned object. By default :class:`~werkzeug.datastructures.RequestCacheControl` is used. :return: a `cls` object. """ if cls is None: cls = RequestCacheControl if not value: return cls(None, on_update) return cls(parse_dict_header(value), on_update) def parse_set_header(value, on_update=None): """Parse a set-like header and return a :class:`~werkzeug.datastructures.HeaderSet` object: >>> hs = parse_set_header('token, "quoted value"') The return value is an object that treats the items case-insensitively and keeps the order of the items: >>> 'TOKEN' in hs True >>> hs.index('quoted value') 1 >>> hs HeaderSet(['token', 'quoted value']) To create a header from the :class:`HeaderSet` again, use the :func:`dump_header` function. :param value: a set header to be parsed. :param on_update: an optional callable that is called every time a value on the :class:`~werkzeug.datastructures.HeaderSet` object is changed. :return: a :class:`~werkzeug.datastructures.HeaderSet` """ if not value: return HeaderSet(None, on_update) return HeaderSet(parse_list_header(value), on_update) def parse_authorization_header(value): """Parse an HTTP basic/digest authorization header transmitted by the web browser. The return value is either `None` if the header was invalid or not given, otherwise an :class:`~werkzeug.datastructures.Authorization` object. :param value: the authorization header to parse. :return: a :class:`~werkzeug.datastructures.Authorization` object or `None`. """ if not value: return value = wsgi_to_bytes(value) try: auth_type, auth_info = value.split(None, 1) auth_type = auth_type.lower() except ValueError: return if auth_type == b"basic": try: username, password = base64.b64decode(auth_info).split(b":", 1) except Exception: return return Authorization( "basic", { "username": to_unicode(username, _basic_auth_charset), "password": to_unicode(password, _basic_auth_charset), }, ) elif auth_type == b"digest": auth_map = parse_dict_header(auth_info) for key in "username", "realm", "nonce", "uri", "response": if key not in auth_map: return if "qop" in auth_map: if not auth_map.get("nc") or not auth_map.get("cnonce"): return return Authorization("digest", auth_map) def parse_www_authenticate_header(value, on_update=None): """Parse an HTTP WWW-Authenticate header into a :class:`~werkzeug.datastructures.WWWAuthenticate` object. :param value: a WWW-Authenticate header to parse. :param on_update: an optional callable that is called every time a value on the :class:`~werkzeug.datastructures.WWWAuthenticate` object is changed. :return: a :class:`~werkzeug.datastructures.WWWAuthenticate` object. """ if not value: return WWWAuthenticate(on_update=on_update) try: auth_type, auth_info = value.split(None, 1) auth_type = auth_type.lower() except (ValueError, AttributeError): return WWWAuthenticate(value.strip().lower(), on_update=on_update) return WWWAuthenticate(auth_type, parse_dict_header(auth_info), on_update) def parse_if_range_header(value): """Parses an if-range header which can be an etag or a date. Returns a :class:`~werkzeug.datastructures.IfRange` object. .. versionadded:: 0.7 """ if not value: return IfRange() date = parse_date(value) if date is not None: return IfRange(date=date) # drop weakness information return IfRange(unquote_etag(value)[0]) def parse_range_header(value, make_inclusive=True): """Parses a range header into a :class:`~werkzeug.datastructures.Range` object. If the header is missing or malformed `None` is returned. `ranges` is a list of ``(start, stop)`` tuples where the ranges are non-inclusive. .. versionadded:: 0.7 """ if not value or "=" not in value: return None ranges = [] last_end = 0 units, rng = value.split("=", 1) units = units.strip().lower() for item in rng.split(","): item = item.strip() if "-" not in item: return None if item.startswith("-"): if last_end < 0: return None try: begin = int(item) except ValueError: return None end = None last_end = -1 elif "-" in item: begin, end = item.split("-", 1) begin = begin.strip() end = end.strip() if not begin.isdigit(): return None begin = int(begin) if begin < last_end or last_end < 0: return None if end: if not end.isdigit(): return None end = int(end) + 1 if begin >= end: return None else: end = None last_end = end ranges.append((begin, end)) return Range(units, ranges) def parse_content_range_header(value, on_update=None): """Parses a range header into a :class:`~werkzeug.datastructures.ContentRange` object or `None` if parsing is not possible. .. versionadded:: 0.7 :param value: a content range header to be parsed. :param on_update: an optional callable that is called every time a value on the :class:`~werkzeug.datastructures.ContentRange` object is changed. """ if value is None: return None try: units, rangedef = (value or "").strip().split(None, 1) except ValueError: return None if "/" not in rangedef: return None rng, length = rangedef.split("/", 1) if length == "*": length = None elif length.isdigit(): length = int(length) else: return None if rng == "*": return ContentRange(units, None, None, length, on_update=on_update) elif "-" not in rng: return None start, stop = rng.split("-", 1) try: start = int(start) stop = int(stop) + 1 except ValueError: return None if is_byte_range_valid(start, stop, length): return ContentRange(units, start, stop, length, on_update=on_update) def quote_etag(etag, weak=False): """Quote an etag. :param etag: the etag to quote. :param weak: set to `True` to tag it "weak". """ if '"' in etag: raise ValueError("invalid etag") etag = '"%s"' % etag if weak: etag = "W/" + etag return etag def unquote_etag(etag): """Unquote a single etag: >>> unquote_etag('W/"bar"') ('bar', True) >>> unquote_etag('"bar"') ('bar', False) :param etag: the etag identifier to unquote. :return: a ``(etag, weak)`` tuple. """ if not etag: return None, None etag = etag.strip() weak = False if etag.startswith(("W/", "w/")): weak = True etag = etag[2:] if etag[:1] == etag[-1:] == '"': etag = etag[1:-1] return etag, weak def parse_etags(value): """Parse an etag header. :param value: the tag header to parse :return: an :class:`~werkzeug.datastructures.ETags` object. """ if not value: return ETags() strong = [] weak = [] end = len(value) pos = 0 while pos < end: match = _etag_re.match(value, pos) if match is None: break is_weak, quoted, raw = match.groups() if raw == "*": return ETags(star_tag=True) elif quoted: raw = quoted if is_weak: weak.append(raw) else: strong.append(raw) pos = match.end() return ETags(strong, weak) def generate_etag(data): """Generate an etag for some data.""" return md5(data).hexdigest() def parse_date(value): """Parse one of the following date formats into a datetime object: .. sourcecode:: text Sun, 06 Nov 1994 08:49:37 GMT ; RFC 822, updated by RFC 1123 Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036 Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format If parsing fails the return value is `None`. :param value: a string with a supported date format. :return: a :class:`datetime.datetime` object. """ if value: t = parsedate_tz(value.strip()) if t is not None: try: year = t[0] # unfortunately that function does not tell us if two digit # years were part of the string, or if they were prefixed # with two zeroes. So what we do is to assume that 69-99 # refer to 1900, and everything below to 2000 if year >= 0 and year <= 68: year += 2000 elif year >= 69 and year <= 99: year += 1900 return datetime(*((year,) + t[1:7])) - timedelta(seconds=t[-1] or 0) except (ValueError, OverflowError): return None def _dump_date(d, delim): """Used for `http_date` and `cookie_date`.""" if d is None: d = gmtime() elif isinstance(d, datetime): d = d.utctimetuple() elif isinstance(d, (integer_types, float)): d = gmtime(d) return "%s, %02d%s%s%s%s %02d:%02d:%02d GMT" % ( ("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun")[d.tm_wday], d.tm_mday, delim, ( "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", )[d.tm_mon - 1], delim, str(d.tm_year), d.tm_hour, d.tm_min, d.tm_sec, ) def cookie_date(expires=None): """Formats the time to ensure compatibility with Netscape's cookie standard. Accepts a floating point number expressed in seconds since the epoch in, a datetime object or a timetuple. All times in UTC. The :func:`parse_date` function can be used to parse such a date. Outputs a string in the format ``Wdy, DD-Mon-YYYY HH:MM:SS GMT``. :param expires: If provided that date is used, otherwise the current. """ return _dump_date(expires, "-") def http_date(timestamp=None): """Formats the time to match the RFC1123 date format. Accepts a floating point number expressed in seconds since the epoch in, a datetime object or a timetuple. All times in UTC. The :func:`parse_date` function can be used to parse such a date. Outputs a string in the format ``Wdy, DD Mon YYYY HH:MM:SS GMT``. :param timestamp: If provided that date is used, otherwise the current. """ return _dump_date(timestamp, " ") def parse_age(value=None): """Parses a base-10 integer count of seconds into a timedelta. If parsing fails, the return value is `None`. :param value: a string consisting of an integer represented in base-10 :return: a :class:`datetime.timedelta` object or `None`. """ if not value: return None try: seconds = int(value) except ValueError: return None if seconds < 0: return None try: return timedelta(seconds=seconds) except OverflowError: return None def dump_age(age=None): """Formats the duration as a base-10 integer. :param age: should be an integer number of seconds, a :class:`datetime.timedelta` object, or, if the age is unknown, `None` (default). """ if age is None: return if isinstance(age, timedelta): # do the equivalent of Python 2.7's timedelta.total_seconds(), # but disregarding fractional seconds age = age.seconds + (age.days * 24 * 3600) age = int(age) if age < 0: raise ValueError("age cannot be negative") return str(age) def is_resource_modified( environ, etag=None, data=None, last_modified=None, ignore_if_range=True ): """Convenience method for conditional requests. :param environ: the WSGI environment of the request to be checked. :param etag: the etag for the response for comparison. :param data: or alternatively the data of the response to automatically generate an etag using :func:`generate_etag`. :param last_modified: an optional date of the last modification. :param ignore_if_range: If `False`, `If-Range` header will be taken into account. :return: `True` if the resource was modified, otherwise `False`. """ if etag is None and data is not None: etag = generate_etag(data) elif data is not None: raise TypeError("both data and etag given") if environ["REQUEST_METHOD"] not in ("GET", "HEAD"): return False unmodified = False if isinstance(last_modified, string_types): last_modified = parse_date(last_modified) # ensure that microsecond is zero because the HTTP spec does not transmit # that either and we might have some false positives. See issue #39 if last_modified is not None: last_modified = last_modified.replace(microsecond=0) if_range = None if not ignore_if_range and "HTTP_RANGE" in environ: # https://tools.ietf.org/html/rfc7233#section-3.2 # A server MUST ignore an If-Range header field received in a request # that does not contain a Range header field. if_range = parse_if_range_header(environ.get("HTTP_IF_RANGE")) if if_range is not None and if_range.date is not None: modified_since = if_range.date else: modified_since = parse_date(environ.get("HTTP_IF_MODIFIED_SINCE")) if modified_since and last_modified and last_modified <= modified_since: unmodified = True if etag: etag, _ = unquote_etag(etag) if if_range is not None and if_range.etag is not None: unmodified = parse_etags(if_range.etag).contains(etag) else: if_none_match = parse_etags(environ.get("HTTP_IF_NONE_MATCH")) if if_none_match: # https://tools.ietf.org/html/rfc7232#section-3.2 # "A recipient MUST use the weak comparison function when comparing # entity-tags for If-None-Match" unmodified = if_none_match.contains_weak(etag) # https://tools.ietf.org/html/rfc7232#section-3.1 # "Origin server MUST use the strong comparison function when # comparing entity-tags for If-Match" if_match = parse_etags(environ.get("HTTP_IF_MATCH")) if if_match: unmodified = not if_match.is_strong(etag) return not unmodified def remove_entity_headers(headers, allowed=("expires", "content-location")): """Remove all entity headers from a list or :class:`Headers` object. This operation works in-place. `Expires` and `Content-Location` headers are by default not removed. The reason for this is :rfc:`2616` section 10.3.5 which specifies some entity headers that should be sent. .. versionchanged:: 0.5 added `allowed` parameter. :param headers: a list or :class:`Headers` object. :param allowed: a list of headers that should still be allowed even though they are entity headers. """ allowed = set(x.lower() for x in allowed) headers[:] = [ (key, value) for key, value in headers if not is_entity_header(key) or key.lower() in allowed ] def remove_hop_by_hop_headers(headers): """Remove all HTTP/1.1 "Hop-by-Hop" headers from a list or :class:`Headers` object. This operation works in-place. .. versionadded:: 0.5 :param headers: a list or :class:`Headers` object. """ headers[:] = [ (key, value) for key, value in headers if not is_hop_by_hop_header(key) ] def is_entity_header(header): """Check if a header is an entity header. .. versionadded:: 0.5 :param header: the header to test. :return: `True` if it's an entity header, `False` otherwise. """ return header.lower() in _entity_headers def is_hop_by_hop_header(header): """Check if a header is an HTTP/1.1 "Hop-by-Hop" header. .. versionadded:: 0.5 :param header: the header to test. :return: `True` if it's an HTTP/1.1 "Hop-by-Hop" header, `False` otherwise. """ return header.lower() in _hop_by_hop_headers def parse_cookie(header, charset="utf-8", errors="replace", cls=None): """Parse a cookie. Either from a string or WSGI environ. Per default encoding errors are ignored. If you want a different behavior you can set `errors` to ``'replace'`` or ``'strict'``. In strict mode a :exc:`HTTPUnicodeError` is raised. .. versionchanged:: 0.5 This function now returns a :class:`TypeConversionDict` instead of a regular dict. The `cls` parameter was added. :param header: the header to be used to parse the cookie. Alternatively this can be a WSGI environment. :param charset: the charset for the cookie values. :param errors: the error behavior for the charset decoding. :param cls: an optional dict class to use. If this is not specified or `None` the default :class:`TypeConversionDict` is used. """ if isinstance(header, dict): header = header.get("HTTP_COOKIE", "") elif header is None: header = "" # If the value is an unicode string it's mangled through latin1. This # is done because on PEP 3333 on Python 3 all headers are assumed latin1 # which however is incorrect for cookies, which are sent in page encoding. # As a result we if isinstance(header, text_type): header = header.encode("latin1", "replace") if cls is None: cls = TypeConversionDict def _parse_pairs(): for key, val in _cookie_parse_impl(header): key = to_unicode(key, charset, errors, allow_none_charset=True) if not key: continue val = to_unicode(val, charset, errors, allow_none_charset=True) yield try_coerce_native(key), val return cls(_parse_pairs()) def dump_cookie( key, value="", max_age=None, expires=None, path="/", domain=None, secure=False, httponly=False, charset="utf-8", sync_expires=True, max_size=4093, samesite=None, ): """Creates a new Set-Cookie header without the ``Set-Cookie`` prefix The parameters are the same as in the cookie Morsel object in the Python standard library but it accepts unicode data, too. On Python 3 the return value of this function will be a unicode string, on Python 2 it will be a native string. In both cases the return value is usually restricted to ascii as the vast majority of values are properly escaped, but that is no guarantee. If a unicode string is returned it's tunneled through latin1 as required by PEP 3333. The return value is not ASCII safe if the key contains unicode characters. This is technically against the specification but happens in the wild. It's strongly recommended to not use non-ASCII values for the keys. :param max_age: should be a number of seconds, or `None` (default) if the cookie should last only as long as the client's browser session. Additionally `timedelta` objects are accepted, too. :param expires: should be a `datetime` object or unix timestamp. :param path: limits the cookie to a given path, per default it will span the whole domain. :param domain: Use this if you want to set a cross-domain cookie. For example, ``domain=".example.com"`` will set a cookie that is readable by the domain ``www.example.com``, ``foo.example.com`` etc. Otherwise, a cookie will only be readable by the domain that set it. :param secure: The cookie will only be available via HTTPS :param httponly: disallow JavaScript to access the cookie. This is an extension to the cookie standard and probably not supported by all browsers. :param charset: the encoding for unicode values. :param sync_expires: automatically set expires if max_age is defined but expires not. :param max_size: Warn if the final header value exceeds this size. The default, 4093, should be safely `supported by most browsers <cookie_>`_. Set to 0 to disable this check. :param samesite: Limits the scope of the cookie such that it will only be attached to requests if those requests are "same-site". .. _`cookie`: http://browsercookielimits.squawky.net/ """ key = to_bytes(key, charset) value = to_bytes(value, charset) if path is not None: from .urls import iri_to_uri path = iri_to_uri(path, charset) domain = _make_cookie_domain(domain) if isinstance(max_age, timedelta): max_age = (max_age.days * 60 * 60 * 24) + max_age.seconds if expires is not None: if not isinstance(expires, string_types): expires = cookie_date(expires) elif max_age is not None and sync_expires: expires = to_bytes(cookie_date(time() + max_age)) samesite = samesite.title() if samesite else None if samesite not in ("Strict", "Lax", None): raise ValueError("invalid SameSite value; must be 'Strict', 'Lax' or None") buf = [key + b"=" + _cookie_quote(value)] # XXX: In theory all of these parameters that are not marked with `None` # should be quoted. Because stdlib did not quote it before I did not # want to introduce quoting there now. for k, v, q in ( (b"Domain", domain, True), (b"Expires", expires, False), (b"Max-Age", max_age, False), (b"Secure", secure, None), (b"HttpOnly", httponly, None), (b"Path", path, False), (b"SameSite", samesite, False), ): if q is None: if v: buf.append(k) continue if v is None: continue tmp = bytearray(k) if not isinstance(v, (bytes, bytearray)): v = to_bytes(text_type(v), charset) if q: v = _cookie_quote(v) tmp += b"=" + v buf.append(bytes(tmp)) # The return value will be an incorrectly encoded latin1 header on # Python 3 for consistency with the headers object and a bytestring # on Python 2 because that's how the API makes more sense. rv = b"; ".join(buf) if not PY2: rv = rv.decode("latin1") # Warn if the final value of the cookie is less than the limit. If the # cookie is too large, then it may be silently ignored, which can be quite # hard to debug. cookie_size = len(rv) if max_size and cookie_size > max_size: value_size = len(value) warnings.warn( 'The "{key}" cookie is too large: the value was {value_size} bytes' " but the header required {extra_size} extra bytes. The final size" " was {cookie_size} bytes but the limit is {max_size} bytes." " Browsers may silently ignore cookies larger than this.".format( key=key, value_size=value_size, extra_size=cookie_size - value_size, cookie_size=cookie_size, max_size=max_size, ), stacklevel=2, ) return rv def is_byte_range_valid(start, stop, length): """Checks if a given byte content range is valid for the given length. .. versionadded:: 0.7 """ if (start is None) != (stop is None): return False elif start is None: return length is None or length >= 0 elif length is None: return 0 <= start < stop elif start >= stop: return False return 0 <= start < length # circular dependencies from .datastructures import Accept from .datastructures import Authorization from .datastructures import ContentRange from .datastructures import ETags from .datastructures import HeaderSet from .datastructures import IfRange from .datastructures import Range from .datastructures import RequestCacheControl from .datastructures import TypeConversionDict from .datastructures import WWWAuthenticate from werkzeug import _DeprecatedImportModule _DeprecatedImportModule( __name__, {".datastructures": ["CharsetAccept", "Headers", "LanguageAccept", "MIMEAccept"]}, "Werkzeug 1.0", ) del _DeprecatedImportModule