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Editing: Cookie.py
#### # Copyright 2000 by Timothy O'Malley <timo@alum.mit.edu> # # All Rights Reserved # # Permission to use, copy, modify, and distribute this software # and its documentation for any purpose and without fee is hereby # granted, provided that the above copyright notice appear in all # copies and that both that copyright notice and this permission # notice appear in supporting documentation, and that the name of # Timothy O'Malley not be used in advertising or publicity # pertaining to distribution of the software without specific, written # prior permission. # # Timothy O'Malley DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS # SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY # AND FITNESS, IN NO EVENT SHALL Timothy O'Malley BE LIABLE FOR # ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, # WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS # ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR # PERFORMANCE OF THIS SOFTWARE. # #### # # Id: Cookie.py,v 2.29 2000/08/23 05:28:49 timo Exp # by Timothy O'Malley <timo@alum.mit.edu> # # Cookie.py is a Python module for the handling of HTTP # cookies as a Python dictionary. See RFC 2109 for more # information on cookies. # # The original idea to treat Cookies as a dictionary came from # Dave Mitchell (davem@magnet.com) in 1995, when he released the # first version of nscookie.py. # #### r""" Here's a sample session to show how to use this module. At the moment, this is the only documentation. The Basics ---------- Importing is easy.. >>> import Cookie Most of the time you start by creating a cookie. Cookies come in three flavors, each with slightly different encoding semantics, but more on that later. >>> C = Cookie.SimpleCookie() >>> C = Cookie.SerialCookie() >>> C = Cookie.SmartCookie() [Note: Long-time users of Cookie.py will remember using Cookie.Cookie() to create a Cookie object. Although deprecated, it is still supported by the code. See the Backward Compatibility notes for more information.] Once you've created your Cookie, you can add values just as if it were a dictionary. >>> C = Cookie.SmartCookie() >>> C["fig"] = "newton" >>> C["sugar"] = "wafer" >>> C.output() 'Set-Cookie: fig=newton\r\nSet-Cookie: sugar=wafer' Notice that the printable representation of a Cookie is the appropriate format for a Set-Cookie: header. This is the default behavior. You can change the header and printed attributes by using the .output() function >>> C = Cookie.SmartCookie() >>> C["rocky"] = "road" >>> C["rocky"]["path"] = "/cookie" >>> print C.output(header="Cookie:") Cookie: rocky=road; Path=/cookie >>> print C.output(attrs=[], header="Cookie:") Cookie: rocky=road The load() method of a Cookie extracts cookies from a string. In a CGI script, you would use this method to extract the cookies from the HTTP_COOKIE environment variable. >>> C = Cookie.SmartCookie() >>> C.load("chips=ahoy; vienna=finger") >>> C.output() 'Set-Cookie: chips=ahoy\r\nSet-Cookie: vienna=finger' The load() method is darn-tootin smart about identifying cookies within a string. Escaped quotation marks, nested semicolons, and other such trickeries do not confuse it. >>> C = Cookie.SmartCookie() >>> C.load('keebler="E=everybody; L=\\"Loves\\"; fudge=\\012;";') >>> print C Set-Cookie: keebler="E=everybody; L=\"Loves\"; fudge=\012;" Each element of the Cookie also supports all of the RFC 2109 Cookie attributes. Here's an example which sets the Path attribute. >>> C = Cookie.SmartCookie() >>> C["oreo"] = "doublestuff" >>> C["oreo"]["path"] = "/" >>> print C Set-Cookie: oreo=doublestuff; Path=/ Each dictionary element has a 'value' attribute, which gives you back the value associated with the key. >>> C = Cookie.SmartCookie() >>> C["twix"] = "none for you" >>> C["twix"].value 'none for you' A Bit More Advanced ------------------- As mentioned before, there are three different flavors of Cookie objects, each with different encoding/decoding semantics. This section briefly discusses the differences. SimpleCookie The SimpleCookie expects that all values should be standard strings. Just to be sure, SimpleCookie invokes the str() builtin to convert the value to a string, when the values are set dictionary-style. >>> C = Cookie.SimpleCookie() >>> C["number"] = 7 >>> C["string"] = "seven" >>> C["number"].value '7' >>> C["string"].value 'seven' >>> C.output() 'Set-Cookie: number=7\r\nSet-Cookie: string=seven' SerialCookie The SerialCookie expects that all values should be serialized using cPickle (or pickle, if cPickle isn't available). As a result of serializing, SerialCookie can save almost any Python object to a value, and recover the exact same object when the cookie has been returned. (SerialCookie can yield some strange-looking cookie values, however.) >>> C = Cookie.SerialCookie() >>> C["number"] = 7 >>> C["string"] = "seven" >>> C["number"].value 7 >>> C["string"].value 'seven' >>> C.output() 'Set-Cookie: number="I7\\012."\r\nSet-Cookie: string="S\'seven\'\\012p1\\012."' Be warned, however, if SerialCookie cannot de-serialize a value (because it isn't a valid pickle'd object), IT WILL RAISE AN EXCEPTION. SmartCookie The SmartCookie combines aspects of each of the other two flavors. When setting a value in a dictionary-fashion, the SmartCookie will serialize (ala cPickle) the value *if and only if* it isn't a Python string. String objects are *not* serialized. Similarly, when the load() method parses out values, it attempts to de-serialize the value. If it fails, then it fallsback to treating the value as a string. >>> C = Cookie.SmartCookie() >>> C["number"] = 7 >>> C["string"] = "seven" >>> C["number"].value 7 >>> C["string"].value 'seven' >>> C.output() 'Set-Cookie: number="I7\\012."\r\nSet-Cookie: string=seven' Backwards Compatibility ----------------------- In order to keep compatibility with earlier versions of Cookie.py, it is still possible to use Cookie.Cookie() to create a Cookie. In fact, this simply returns a SmartCookie. >>> C = Cookie.Cookie() >>> print C.__class__.__name__ SmartCookie Finis. """ #" # ^ # |----helps out font-lock # # Import our required modules # import string try: from cPickle import dumps, loads except ImportError: from pickle import dumps, loads import re, warnings __all__ = ["CookieError","BaseCookie","SimpleCookie","SerialCookie", "SmartCookie","Cookie"] _nulljoin = ''.join _semispacejoin = '; '.join _spacejoin = ' '.join # # Define an exception visible to External modules # class CookieError(Exception): pass # These quoting routines conform to the RFC2109 specification, which in # turn references the character definitions from RFC2068. They provide # a two-way quoting algorithm. Any non-text character is translated # into a 4 character sequence: a forward-slash followed by the # three-digit octal equivalent of the character. Any '\' or '"' is # quoted with a preceding '\' slash. # # These are taken from RFC2068 and RFC2109. # _LegalChars is the list of chars which don't require "'s # _Translator hash-table for fast quoting # _LegalChars = string.ascii_letters + string.digits + "!#$%&'*+-.^_`|~" _Translator = { '\000' : '\\000', '\001' : '\\001', '\002' : '\\002', '\003' : '\\003', '\004' : '\\004', '\005' : '\\005', '\006' : '\\006', '\007' : '\\007', '\010' : '\\010', '\011' : '\\011', '\012' : '\\012', '\013' : '\\013', '\014' : '\\014', '\015' : '\\015', '\016' : '\\016', '\017' : '\\017', '\020' : '\\020', '\021' : '\\021', '\022' : '\\022', '\023' : '\\023', '\024' : '\\024', '\025' : '\\025', '\026' : '\\026', '\027' : '\\027', '\030' : '\\030', '\031' : '\\031', '\032' : '\\032', '\033' : '\\033', '\034' : '\\034', '\035' : '\\035', '\036' : '\\036', '\037' : '\\037', # Because of the way browsers really handle cookies (as opposed # to what the RFC says) we also encode , and ; ',' : '\\054', ';' : '\\073', '"' : '\\"', '\\' : '\\\\', '\177' : '\\177', '\200' : '\\200', '\201' : '\\201', '\202' : '\\202', '\203' : '\\203', '\204' : '\\204', '\205' : '\\205', '\206' : '\\206', '\207' : '\\207', '\210' : '\\210', '\211' : '\\211', '\212' : '\\212', '\213' : '\\213', '\214' : '\\214', '\215' : '\\215', '\216' : '\\216', '\217' : '\\217', '\220' : '\\220', '\221' : '\\221', '\222' : '\\222', '\223' : '\\223', '\224' : '\\224', '\225' : '\\225', '\226' : '\\226', '\227' : '\\227', '\230' : '\\230', '\231' : '\\231', '\232' : '\\232', '\233' : '\\233', '\234' : '\\234', '\235' : '\\235', '\236' : '\\236', '\237' : '\\237', '\240' : '\\240', '\241' : '\\241', '\242' : '\\242', '\243' : '\\243', '\244' : '\\244', '\245' : '\\245', '\246' : '\\246', '\247' : '\\247', '\250' : '\\250', '\251' : '\\251', '\252' : '\\252', '\253' : '\\253', '\254' : '\\254', '\255' : '\\255', '\256' : '\\256', '\257' : '\\257', '\260' : '\\260', '\261' : '\\261', '\262' : '\\262', '\263' : '\\263', '\264' : '\\264', '\265' : '\\265', '\266' : '\\266', '\267' : '\\267', '\270' : '\\270', '\271' : '\\271', '\272' : '\\272', '\273' : '\\273', '\274' : '\\274', '\275' : '\\275', '\276' : '\\276', '\277' : '\\277', '\300' : '\\300', '\301' : '\\301', '\302' : '\\302', '\303' : '\\303', '\304' : '\\304', '\305' : '\\305', '\306' : '\\306', '\307' : '\\307', '\310' : '\\310', '\311' : '\\311', '\312' : '\\312', '\313' : '\\313', '\314' : '\\314', '\315' : '\\315', '\316' : '\\316', '\317' : '\\317', '\320' : '\\320', '\321' : '\\321', '\322' : '\\322', '\323' : '\\323', '\324' : '\\324', '\325' : '\\325', '\326' : '\\326', '\327' : '\\327', '\330' : '\\330', '\331' : '\\331', '\332' : '\\332', '\333' : '\\333', '\334' : '\\334', '\335' : '\\335', '\336' : '\\336', '\337' : '\\337', '\340' : '\\340', '\341' : '\\341', '\342' : '\\342', '\343' : '\\343', '\344' : '\\344', '\345' : '\\345', '\346' : '\\346', '\347' : '\\347', '\350' : '\\350', '\351' : '\\351', '\352' : '\\352', '\353' : '\\353', '\354' : '\\354', '\355' : '\\355', '\356' : '\\356', '\357' : '\\357', '\360' : '\\360', '\361' : '\\361', '\362' : '\\362', '\363' : '\\363', '\364' : '\\364', '\365' : '\\365', '\366' : '\\366', '\367' : '\\367', '\370' : '\\370', '\371' : '\\371', '\372' : '\\372', '\373' : '\\373', '\374' : '\\374', '\375' : '\\375', '\376' : '\\376', '\377' : '\\377' } _idmap = ''.join(chr(x) for x in xrange(256)) def _quote(str, LegalChars=_LegalChars, idmap=_idmap, translate=string.translate): # # If the string does not need to be double-quoted, # then just return the string. Otherwise, surround # the string in doublequotes and precede quote (with a \) # special characters. # if "" == translate(str, idmap, LegalChars): return str else: return '"' + _nulljoin( map(_Translator.get, str, str) ) + '"' # end _quote _OctalPatt = re.compile(r"\\[0-3][0-7][0-7]") _QuotePatt = re.compile(r"[\\].") def _unquote(str): # If there aren't any doublequotes, # then there can't be any special characters. See RFC 2109. if len(str) < 2: return str if str[0] != '"' or str[-1] != '"': return str # We have to assume that we must decode this string. # Down to work. # Remove the "s str = str[1:-1] # Check for special sequences. Examples: # \012 --> \n # \" --> " # i = 0 n = len(str) res = [] while 0 <= i < n: Omatch = _OctalPatt.search(str, i) Qmatch = _QuotePatt.search(str, i) if not Omatch and not Qmatch: # Neither matched res.append(str[i:]) break # else: j = k = -1 if Omatch: j = Omatch.start(0) if Qmatch: k = Qmatch.start(0) if Qmatch and ( not Omatch or k < j ): # QuotePatt matched res.append(str[i:k]) res.append(str[k+1]) i = k+2 else: # OctalPatt matched res.append(str[i:j]) res.append( chr( int(str[j+1:j+4], 8) ) ) i = j+4 return _nulljoin(res) # end _unquote # The _getdate() routine is used to set the expiration time in # the cookie's HTTP header. By default, _getdate() returns the # current time in the appropriate "expires" format for a # Set-Cookie header. The one optional argument is an offset from # now, in seconds. For example, an offset of -3600 means "one hour ago". # The offset may be a floating point number. # _weekdayname = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'] _monthname = [None, 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'] def _getdate(future=0, weekdayname=_weekdayname, monthname=_monthname): from time import gmtime, time now = time() year, month, day, hh, mm, ss, wd, y, z = gmtime(now + future) return "%s, %02d %3s %4d %02d:%02d:%02d GMT" % \ (weekdayname[wd], day, monthname[month], year, hh, mm, ss) # # A class to hold ONE key,value pair. # In a cookie, each such pair may have several attributes. # so this class is used to keep the attributes associated # with the appropriate key,value pair. # This class also includes a coded_value attribute, which # is used to hold the network representation of the # value. This is most useful when Python objects are # pickled for network transit. # class Morsel(dict): # RFC 2109 lists these attributes as reserved: # path comment domain # max-age secure version # # For historical reasons, these attributes are also reserved: # expires # # This is an extension from Microsoft: # httponly # # This dictionary provides a mapping from the lowercase # variant on the left to the appropriate traditional # formatting on the right. _reserved = { "expires" : "expires", "path" : "Path", "comment" : "Comment", "domain" : "Domain", "max-age" : "Max-Age", "secure" : "secure", "httponly" : "httponly", "version" : "Version", } _flags = {'secure', 'httponly'} def __init__(self): # Set defaults self.key = self.value = self.coded_value = None # Set default attributes for K in self._reserved: dict.__setitem__(self, K, "") # end __init__ def __setitem__(self, K, V): K = K.lower() if not K in self._reserved: raise CookieError("Invalid Attribute %s" % K) dict.__setitem__(self, K, V) # end __setitem__ def isReservedKey(self, K): return K.lower() in self._reserved # end isReservedKey def set(self, key, val, coded_val, LegalChars=_LegalChars, idmap=_idmap, translate=string.translate): # First we verify that the key isn't a reserved word # Second we make sure it only contains legal characters if key.lower() in self._reserved: raise CookieError("Attempt to set a reserved key: %s" % key) if "" != translate(key, idmap, LegalChars): raise CookieError("Illegal key value: %s" % key) # It's a good key, so save it. self.key = key self.value = val self.coded_value = coded_val # end set def output(self, attrs=None, header = "Set-Cookie:"): return "%s %s" % ( header, self.OutputString(attrs) ) __str__ = output def __repr__(self): return '<%s: %s=%s>' % (self.__class__.__name__, self.key, repr(self.value) ) def js_output(self, attrs=None): # Print javascript return """ <script type="text/javascript"> <!-- begin hiding document.cookie = \"%s\"; // end hiding --> </script> """ % ( self.OutputString(attrs).replace('"',r'\"'), ) # end js_output() def OutputString(self, attrs=None): # Build up our result # result = [] RA = result.append # First, the key=value pair RA("%s=%s" % (self.key, self.coded_value)) # Now add any defined attributes if attrs is None: attrs = self._reserved items = self.items() items.sort() for K,V in items: if V == "": continue if K not in attrs: continue if K == "expires" and type(V) == type(1): RA("%s=%s" % (self._reserved[K], _getdate(V))) elif K == "max-age" and type(V) == type(1): RA("%s=%d" % (self._reserved[K], V)) elif K == "secure": RA(str(self._reserved[K])) elif K == "httponly": RA(str(self._reserved[K])) else: RA("%s=%s" % (self._reserved[K], V)) # Return the result return _semispacejoin(result) # end OutputString # end Morsel class # # Pattern for finding cookie # # This used to be strict parsing based on the RFC2109 and RFC2068 # specifications. I have since discovered that MSIE 3.0x doesn't # follow the character rules outlined in those specs. As a # result, the parsing rules here are less strict. # _LegalKeyChars = r"\w\d!#%&'~_`><@,:/\$\*\+\-\.\^\|\)\(\?\}\{\=" _LegalValueChars = _LegalKeyChars + r"\[\]" _CookiePattern = re.compile( r"(?x)" # This is a Verbose pattern r"\s*" # Optional whitespace at start of cookie r"(?P<key>" # Start of group 'key' "["+ _LegalKeyChars +"]+?" # Any word of at least one letter, nongreedy r")" # End of group 'key' r"(" # Optional group: there may not be a value. r"\s*=\s*" # Equal Sign r"(?P<val>" # Start of group 'val' r'"(?:[^\\"]|\\.)*"' # Any doublequoted string r"|" # or r"\w{3},\s[\s\w\d-]{9,11}\s[\d:]{8}\sGMT" # Special case for "expires" attr r"|" # or "["+ _LegalValueChars +"]*" # Any word or empty string r")" # End of group 'val' r")?" # End of optional value group r"\s*" # Any number of spaces. r"(\s+|;|$)" # Ending either at space, semicolon, or EOS. ) # At long last, here is the cookie class. # Using this class is almost just like using a dictionary. # See this module's docstring for example usage. # class BaseCookie(dict): # A container class for a set of Morsels # def value_decode(self, val): """real_value, coded_value = value_decode(STRING) Called prior to setting a cookie's value from the network representation. The VALUE is the value read from HTTP header. Override this function to modify the behavior of cookies. """ return val, val # end value_encode def value_encode(self, val): """real_value, coded_value = value_encode(VALUE) Called prior to setting a cookie's value from the dictionary representation. The VALUE is the value being assigned. Override this function to modify the behavior of cookies. """ strval = str(val) return strval, strval # end value_encode def __init__(self, input=None): if input: self.load(input) # end __init__ def __set(self, key, real_value, coded_value): """Private method for setting a cookie's value""" M = self.get(key, Morsel()) M.set(key, real_value, coded_value) dict.__setitem__(self, key, M) # end __set def __setitem__(self, key, value): """Dictionary style assignment.""" if isinstance(value, Morsel): # allow assignment of constructed Morsels (e.g. for pickling) dict.__setitem__(self, key, value) else: rval, cval = self.value_encode(value) self.__set(key, rval, cval) # end __setitem__ def output(self, attrs=None, header="Set-Cookie:", sep="\015\012"): """Return a string suitable for HTTP.""" result = [] items = self.items() items.sort() for K,V in items: result.append( V.output(attrs, header) ) return sep.join(result) # end output __str__ = output def __repr__(self): L = [] items = self.items() items.sort() for K,V in items: L.append( '%s=%s' % (K,repr(V.value) ) ) return '<%s: %s>' % (self.__class__.__name__, _spacejoin(L)) def js_output(self, attrs=None): """Return a string suitable for JavaScript.""" result = [] items = self.items() items.sort() for K,V in items: result.append( V.js_output(attrs) ) return _nulljoin(result) # end js_output def load(self, rawdata): """Load cookies from a string (presumably HTTP_COOKIE) or from a dictionary. Loading cookies from a dictionary 'd' is equivalent to calling: map(Cookie.__setitem__, d.keys(), d.values()) """ if type(rawdata) == type(""): self.__ParseString(rawdata) else: # self.update() wouldn't call our custom __setitem__ for k, v in rawdata.items(): self[k] = v return # end load() def __ParseString(self, str, patt=_CookiePattern): i = 0 # Our starting point n = len(str) # Length of string M = None # current morsel while 0 <= i < n: # Start looking for a cookie match = patt.match(str, i) if not match: break # No more cookies K,V = match.group("key"), match.group("val") i = match.end(0) # Parse the key, value in case it's metainfo if K[0] == "$": # We ignore attributes which pertain to the cookie # mechanism as a whole. See RFC 2109. # (Does anyone care?) if M: M[ K[1:] ] = V elif K.lower() in Morsel._reserved: if M: if V is None: if K.lower() in Morsel._flags: M[K] = True else: M[K] = _unquote(V) elif V is not None: rval, cval = self.value_decode(V) self.__set(K, rval, cval) M = self[K] # end __ParseString # end BaseCookie class class SimpleCookie(BaseCookie): """SimpleCookie SimpleCookie supports strings as cookie values. When setting the value using the dictionary assignment notation, SimpleCookie calls the builtin str() to convert the value to a string. Values received from HTTP are kept as strings. """ def value_decode(self, val): return _unquote( val ), val def value_encode(self, val): strval = str(val) return strval, _quote( strval ) # end SimpleCookie class SerialCookie(BaseCookie): """SerialCookie SerialCookie supports arbitrary objects as cookie values. All values are serialized (using cPickle) before being sent to the client. All incoming values are assumed to be valid Pickle representations. IF AN INCOMING VALUE IS NOT IN A VALID PICKLE FORMAT, THEN AN EXCEPTION WILL BE RAISED. Note: Large cookie values add overhead because they must be retransmitted on every HTTP transaction. Note: HTTP has a 2k limit on the size of a cookie. This class does not check for this limit, so be careful!!! """ def __init__(self, input=None): warnings.warn("SerialCookie class is insecure; do not use it", DeprecationWarning) BaseCookie.__init__(self, input) # end __init__ def value_decode(self, val): # This could raise an exception! return loads( _unquote(val) ), val def value_encode(self, val): return val, _quote( dumps(val) ) # end SerialCookie class SmartCookie(BaseCookie): """SmartCookie SmartCookie supports arbitrary objects as cookie values. If the object is a string, then it is quoted. If the object is not a string, however, then SmartCookie will use cPickle to serialize the object into a string representation. Note: Large cookie values add overhead because they must be retransmitted on every HTTP transaction. Note: HTTP has a 2k limit on the size of a cookie. This class does not check for this limit, so be careful!!! """ def __init__(self, input=None): warnings.warn("Cookie/SmartCookie class is insecure; do not use it", DeprecationWarning) BaseCookie.__init__(self, input) # end __init__ def value_decode(self, val): strval = _unquote(val) try: return loads(strval), val except: return strval, val def value_encode(self, val): if type(val) == type(""): return val, _quote(val) else: return val, _quote( dumps(val) ) # end SmartCookie ########################################################### # Backwards Compatibility: Don't break any existing code! # We provide Cookie() as an alias for SmartCookie() Cookie = SmartCookie # ########################################################### def _test(): import doctest, Cookie return doctest.testmod(Cookie) if __name__ == "__main__": _test() #Local Variables: #tab-width: 4 #end:
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