134 lines
2.9 KiB
Python
134 lines
2.9 KiB
Python
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"""
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A flexible module for cookie parsing and manipulation.
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We try to be as permissive as possible. Parsing accepts formats from RFC6265 an
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RFC2109. Serialization follows RFC6265 strictly.
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http://tools.ietf.org/html/rfc6265
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http://tools.ietf.org/html/rfc2109
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"""
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import re
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import odict
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def _read_until(s, start, term):
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"""
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Read until one of the characters in term is reached.
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"""
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if start == len(s):
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return "", start+1
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for i in range(start, len(s)):
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if s[i] in term:
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return s[start:i], i
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return s[start:i+1], i+1
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def _read_token(s, start):
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"""
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Read a token - the LHS of a token/value pair in a cookie.
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"""
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return _read_until(s, start, ";=")
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def _read_quoted_string(s, start):
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"""
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start: offset to the first quote of the string to be read
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A sort of loose super-set of the various quoted string specifications.
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RFC6265 disallows backslashes or double quotes within quoted strings.
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Prior RFCs use backslashes to escape. This leaves us free to apply
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backslash escaping by default and be compatible with everything.
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"""
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escaping = False
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ret = []
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# Skip the first quote
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for i in range(start+1, len(s)):
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if escaping:
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ret.append(s[i])
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escaping = False
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elif s[i] == '"':
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break
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elif s[i] == "\\":
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escaping = True
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pass
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else:
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ret.append(s[i])
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return "".join(ret), i+1
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def _read_value(s, start):
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"""
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Reads a value - the RHS of a token/value pair in a cookie.
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"""
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if s[start] == '"':
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return _read_quoted_string(s, start)
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else:
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return _read_until(s, start, ";,")
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def _read_pairs(s):
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"""
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Read pairs of lhs=rhs values.
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"""
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off = 0
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vals = []
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while 1:
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lhs, off = _read_token(s, off)
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rhs = None
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if off < len(s):
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if s[off] == "=":
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rhs, off = _read_value(s, off+1)
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vals.append([lhs.lstrip(), rhs])
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off += 1
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if not off < len(s):
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break
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return vals, off
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ESCAPE = re.compile(r"([\"\\])")
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SPECIAL = re.compile(r"^\w+$")
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def _format_pairs(lst):
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vals = []
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for k, v in lst:
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if v is None:
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vals.append(k)
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else:
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match = SPECIAL.search(v)
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if match:
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v = ESCAPE.sub(r"\1", v)
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vals.append("%s=%s"%(k, v))
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return "; ".join(vals)
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def parse_cookies(s):
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"""
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Parses a Cookie header value.
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Returns an ODict object.
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"""
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pairs, off = _read_pairs(s)
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return odict.ODict(pairs)
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def unparse_cookies(od):
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"""
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Formats a Cookie header value.
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"""
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vals = []
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for i in od.lst:
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vals.append("%s=%s"%(i[0], i[1]))
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return "; ".join(vals)
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def parse_set_cookies(s):
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start = 0
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def unparse_set_cookies(s):
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pass
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