69 lines
1.9 KiB
Python
69 lines
1.9 KiB
Python
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# -*- test-case-name: twisted.web.test.test_abnf -*-
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# Copyright (c) Twisted Matrix Laboratories.
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# See LICENSE for details.
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"""
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Tools for pedantically processing the HTTP protocol.
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"""
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def _istoken(b: bytes) -> bool:
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"""
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Is the string a token per RFC 9110 section 5.6.2?
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"""
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for c in b:
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if c not in (
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b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" # ALPHA
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b"0123456789" # DIGIT
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b"!#$%&'*+-.^_`|~"
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):
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return False
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return b != b""
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def _decint(data: bytes) -> int:
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"""
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Parse a decimal integer of the form C{1*DIGIT}, i.e. consisting only of
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decimal digits. The integer may be embedded in whitespace (space and
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horizontal tab). This differs from the built-in L{int()} function by
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disallowing a leading C{+} character and various forms of whitespace
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(note that we sanitize linear whitespace in header values in
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L{twisted.web.http_headers.Headers}).
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@param data: Value to parse.
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@returns: A non-negative integer.
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@raises ValueError: When I{value} contains non-decimal characters.
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"""
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data = data.strip(b" \t")
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if not data.isdigit():
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raise ValueError(f"Value contains non-decimal digits: {data!r}")
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return int(data)
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def _ishexdigits(b: bytes) -> bool:
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"""
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Is the string case-insensitively hexidecimal?
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It must be composed of one or more characters in the ranges a-f, A-F
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and 0-9.
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"""
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for c in b:
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if c not in b"0123456789abcdefABCDEF":
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return False
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return b != b""
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def _hexint(b: bytes) -> int:
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"""
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Decode a hexadecimal integer.
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Unlike L{int(b, 16)}, this raises L{ValueError} when the integer has
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a prefix like C{b'0x'}, C{b'+'}, or C{b'-'}, which is desirable when
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parsing network protocols.
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"""
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if not _ishexdigits(b):
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raise ValueError(b)
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return int(b, 16)
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