RAHHH

backend/lib/python3.12/site-packages/twisted/web/_abnf.py

@@ -0,0 +1,68 @@
+# -*- test-case-name: twisted.web.test.test_abnf -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Tools for pedantically processing the HTTP protocol.
+"""
+
+
+def _istoken(b: bytes) -> bool:
+    """
+    Is the string a token per RFC 9110 section 5.6.2?
+    """
+    for c in b:
+        if c not in (
+            b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"  # ALPHA
+            b"0123456789"  # DIGIT
+            b"!#$%&'*+-.^_`|~"
+        ):
+            return False
+    return b != b""
+
+
+def _decint(data: bytes) -> int:
+    """
+    Parse a decimal integer of the form C{1*DIGIT}, i.e. consisting only of
+    decimal digits. The integer may be embedded in whitespace (space and
+    horizontal tab). This differs from the built-in L{int()} function by
+    disallowing a leading C{+} character and various forms of whitespace
+    (note that we sanitize linear whitespace in header values in
+    L{twisted.web.http_headers.Headers}).
+
+    @param data: Value to parse.
+
+    @returns: A non-negative integer.
+
+    @raises ValueError: When I{value} contains non-decimal characters.
+    """
+    data = data.strip(b" \t")
+    if not data.isdigit():
+        raise ValueError(f"Value contains non-decimal digits: {data!r}")
+    return int(data)
+
+
+def _ishexdigits(b: bytes) -> bool:
+    """
+    Is the string case-insensitively hexidecimal?
+
+    It must be composed of one or more characters in the ranges a-f, A-F
+    and 0-9.
+    """
+    for c in b:
+        if c not in b"0123456789abcdefABCDEF":
+            return False
+    return b != b""
+
+
+def _hexint(b: bytes) -> int:
+    """
+    Decode a hexadecimal integer.
+
+    Unlike L{int(b, 16)}, this raises L{ValueError} when the integer has
+    a prefix like C{b'0x'}, C{b'+'}, or C{b'-'}, which is desirable when
+    parsing network protocols.
+    """
+    if not _ishexdigits(b):
+        raise ValueError(b)
+    return int(b, 16)