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438 lines
13 KiB
Python
438 lines
13 KiB
Python
import bisect
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import re
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import unicodedata
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from typing import Optional, Union
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from . import idnadata
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from .intranges import intranges_contain
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_virama_combining_class = 9
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_alabel_prefix = b"xn--"
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_unicode_dots_re = re.compile("[\u002e\u3002\uff0e\uff61]")
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class IDNAError(UnicodeError):
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"""Base exception for all IDNA-encoding related problems"""
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pass
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class IDNABidiError(IDNAError):
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"""Exception when bidirectional requirements are not satisfied"""
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pass
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class InvalidCodepoint(IDNAError):
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"""Exception when a disallowed or unallocated codepoint is used"""
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pass
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class InvalidCodepointContext(IDNAError):
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"""Exception when the codepoint is not valid in the context it is used"""
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pass
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def _combining_class(cp: int) -> int:
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v = unicodedata.combining(chr(cp))
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if v == 0:
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if not unicodedata.name(chr(cp)):
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raise ValueError("Unknown character in unicodedata")
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return v
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def _is_script(cp: str, script: str) -> bool:
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return intranges_contain(ord(cp), idnadata.scripts[script])
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def _punycode(s: str) -> bytes:
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return s.encode("punycode")
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def _unot(s: int) -> str:
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return "U+{:04X}".format(s)
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def valid_label_length(label: Union[bytes, str]) -> bool:
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if len(label) > 63:
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return False
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return True
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def valid_string_length(label: Union[bytes, str], trailing_dot: bool) -> bool:
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if len(label) > (254 if trailing_dot else 253):
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return False
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return True
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def check_bidi(label: str, check_ltr: bool = False) -> bool:
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# Bidi rules should only be applied if string contains RTL characters
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bidi_label = False
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for idx, cp in enumerate(label, 1):
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direction = unicodedata.bidirectional(cp)
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if direction == "":
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# String likely comes from a newer version of Unicode
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raise IDNABidiError("Unknown directionality in label {} at position {}".format(repr(label), idx))
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if direction in ["R", "AL", "AN"]:
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bidi_label = True
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if not bidi_label and not check_ltr:
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return True
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# Bidi rule 1
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direction = unicodedata.bidirectional(label[0])
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if direction in ["R", "AL"]:
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rtl = True
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elif direction == "L":
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rtl = False
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else:
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raise IDNABidiError("First codepoint in label {} must be directionality L, R or AL".format(repr(label)))
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valid_ending = False
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number_type: Optional[str] = None
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for idx, cp in enumerate(label, 1):
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direction = unicodedata.bidirectional(cp)
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if rtl:
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# Bidi rule 2
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if direction not in [
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"R",
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"AL",
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"AN",
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"EN",
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"ES",
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"CS",
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"ET",
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"ON",
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"BN",
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"NSM",
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]:
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raise IDNABidiError("Invalid direction for codepoint at position {} in a right-to-left label".format(idx))
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# Bidi rule 3
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if direction in ["R", "AL", "EN", "AN"]:
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valid_ending = True
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elif direction != "NSM":
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valid_ending = False
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# Bidi rule 4
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if direction in ["AN", "EN"]:
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if not number_type:
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number_type = direction
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else:
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if number_type != direction:
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raise IDNABidiError("Can not mix numeral types in a right-to-left label")
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else:
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# Bidi rule 5
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if direction not in ["L", "EN", "ES", "CS", "ET", "ON", "BN", "NSM"]:
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raise IDNABidiError("Invalid direction for codepoint at position {} in a left-to-right label".format(idx))
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# Bidi rule 6
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if direction in ["L", "EN"]:
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valid_ending = True
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elif direction != "NSM":
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valid_ending = False
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if not valid_ending:
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raise IDNABidiError("Label ends with illegal codepoint directionality")
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return True
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def check_initial_combiner(label: str) -> bool:
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if unicodedata.category(label[0])[0] == "M":
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raise IDNAError("Label begins with an illegal combining character")
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return True
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def check_hyphen_ok(label: str) -> bool:
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if label[2:4] == "--":
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raise IDNAError("Label has disallowed hyphens in 3rd and 4th position")
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if label[0] == "-" or label[-1] == "-":
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raise IDNAError("Label must not start or end with a hyphen")
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return True
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def check_nfc(label: str) -> None:
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if unicodedata.normalize("NFC", label) != label:
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raise IDNAError("Label must be in Normalization Form C")
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def valid_contextj(label: str, pos: int) -> bool:
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cp_value = ord(label[pos])
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if cp_value == 0x200C:
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if pos > 0:
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if _combining_class(ord(label[pos - 1])) == _virama_combining_class:
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return True
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ok = False
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for i in range(pos - 1, -1, -1):
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joining_type = idnadata.joining_types.get(ord(label[i]))
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if joining_type == ord("T"):
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continue
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elif joining_type in [ord("L"), ord("D")]:
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ok = True
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break
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else:
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break
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if not ok:
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return False
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ok = False
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for i in range(pos + 1, len(label)):
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joining_type = idnadata.joining_types.get(ord(label[i]))
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if joining_type == ord("T"):
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continue
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elif joining_type in [ord("R"), ord("D")]:
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ok = True
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break
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else:
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break
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return ok
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if cp_value == 0x200D:
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if pos > 0:
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if _combining_class(ord(label[pos - 1])) == _virama_combining_class:
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return True
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return False
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else:
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return False
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def valid_contexto(label: str, pos: int, exception: bool = False) -> bool:
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cp_value = ord(label[pos])
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if cp_value == 0x00B7:
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if 0 < pos < len(label) - 1:
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if ord(label[pos - 1]) == 0x006C and ord(label[pos + 1]) == 0x006C:
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return True
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return False
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elif cp_value == 0x0375:
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if pos < len(label) - 1 and len(label) > 1:
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return _is_script(label[pos + 1], "Greek")
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return False
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elif cp_value == 0x05F3 or cp_value == 0x05F4:
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if pos > 0:
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return _is_script(label[pos - 1], "Hebrew")
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return False
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elif cp_value == 0x30FB:
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for cp in label:
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if cp == "\u30fb":
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continue
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if _is_script(cp, "Hiragana") or _is_script(cp, "Katakana") or _is_script(cp, "Han"):
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return True
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return False
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elif 0x660 <= cp_value <= 0x669:
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for cp in label:
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if 0x6F0 <= ord(cp) <= 0x06F9:
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return False
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return True
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elif 0x6F0 <= cp_value <= 0x6F9:
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for cp in label:
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if 0x660 <= ord(cp) <= 0x0669:
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return False
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return True
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return False
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def check_label(label: Union[str, bytes, bytearray]) -> None:
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if isinstance(label, (bytes, bytearray)):
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label = label.decode("utf-8")
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if len(label) == 0:
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raise IDNAError("Empty Label")
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check_nfc(label)
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check_hyphen_ok(label)
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check_initial_combiner(label)
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for pos, cp in enumerate(label):
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cp_value = ord(cp)
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if intranges_contain(cp_value, idnadata.codepoint_classes["PVALID"]):
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continue
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elif intranges_contain(cp_value, idnadata.codepoint_classes["CONTEXTJ"]):
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try:
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if not valid_contextj(label, pos):
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raise InvalidCodepointContext(
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"Joiner {} not allowed at position {} in {}".format(_unot(cp_value), pos + 1, repr(label))
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)
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except ValueError:
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raise IDNAError(
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"Unknown codepoint adjacent to joiner {} at position {} in {}".format(
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_unot(cp_value), pos + 1, repr(label)
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)
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)
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elif intranges_contain(cp_value, idnadata.codepoint_classes["CONTEXTO"]):
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if not valid_contexto(label, pos):
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raise InvalidCodepointContext(
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"Codepoint {} not allowed at position {} in {}".format(_unot(cp_value), pos + 1, repr(label))
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)
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else:
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raise InvalidCodepoint(
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"Codepoint {} at position {} of {} not allowed".format(_unot(cp_value), pos + 1, repr(label))
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)
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check_bidi(label)
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def alabel(label: str) -> bytes:
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try:
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label_bytes = label.encode("ascii")
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ulabel(label_bytes)
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if not valid_label_length(label_bytes):
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raise IDNAError("Label too long")
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return label_bytes
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except UnicodeEncodeError:
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pass
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check_label(label)
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label_bytes = _alabel_prefix + _punycode(label)
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if not valid_label_length(label_bytes):
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raise IDNAError("Label too long")
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return label_bytes
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def ulabel(label: Union[str, bytes, bytearray]) -> str:
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if not isinstance(label, (bytes, bytearray)):
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try:
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label_bytes = label.encode("ascii")
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except UnicodeEncodeError:
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check_label(label)
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return label
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else:
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label_bytes = label
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label_bytes = label_bytes.lower()
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if label_bytes.startswith(_alabel_prefix):
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label_bytes = label_bytes[len(_alabel_prefix) :]
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if not label_bytes:
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raise IDNAError("Malformed A-label, no Punycode eligible content found")
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if label_bytes.decode("ascii")[-1] == "-":
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raise IDNAError("A-label must not end with a hyphen")
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else:
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check_label(label_bytes)
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return label_bytes.decode("ascii")
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try:
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label = label_bytes.decode("punycode")
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except UnicodeError:
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raise IDNAError("Invalid A-label")
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check_label(label)
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return label
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def uts46_remap(domain: str, std3_rules: bool = True, transitional: bool = False) -> str:
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"""Re-map the characters in the string according to UTS46 processing."""
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from .uts46data import uts46data
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output = ""
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for pos, char in enumerate(domain):
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code_point = ord(char)
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try:
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uts46row = uts46data[code_point if code_point < 256 else bisect.bisect_left(uts46data, (code_point, "Z")) - 1]
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status = uts46row[1]
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replacement: Optional[str] = None
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if len(uts46row) == 3:
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replacement = uts46row[2]
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if (
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status == "V"
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or (status == "D" and not transitional)
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or (status == "3" and not std3_rules and replacement is None)
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):
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output += char
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elif replacement is not None and (
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status == "M" or (status == "3" and not std3_rules) or (status == "D" and transitional)
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):
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output += replacement
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elif status != "I":
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raise IndexError()
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except IndexError:
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raise InvalidCodepoint(
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"Codepoint {} not allowed at position {} in {}".format(_unot(code_point), pos + 1, repr(domain))
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)
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return unicodedata.normalize("NFC", output)
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def encode(
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s: Union[str, bytes, bytearray],
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strict: bool = False,
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uts46: bool = False,
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std3_rules: bool = False,
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transitional: bool = False,
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) -> bytes:
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if not isinstance(s, str):
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try:
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s = str(s, "ascii")
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except UnicodeDecodeError:
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raise IDNAError("should pass a unicode string to the function rather than a byte string.")
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if uts46:
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s = uts46_remap(s, std3_rules, transitional)
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trailing_dot = False
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result = []
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if strict:
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labels = s.split(".")
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else:
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labels = _unicode_dots_re.split(s)
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if not labels or labels == [""]:
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raise IDNAError("Empty domain")
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if labels[-1] == "":
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del labels[-1]
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trailing_dot = True
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for label in labels:
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s = alabel(label)
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if s:
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result.append(s)
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else:
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raise IDNAError("Empty label")
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if trailing_dot:
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result.append(b"")
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s = b".".join(result)
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if not valid_string_length(s, trailing_dot):
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raise IDNAError("Domain too long")
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return s
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def decode(
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s: Union[str, bytes, bytearray],
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strict: bool = False,
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uts46: bool = False,
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std3_rules: bool = False,
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) -> str:
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try:
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if not isinstance(s, str):
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s = str(s, "ascii")
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except UnicodeDecodeError:
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raise IDNAError("Invalid ASCII in A-label")
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if uts46:
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s = uts46_remap(s, std3_rules, False)
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trailing_dot = False
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result = []
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if not strict:
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labels = _unicode_dots_re.split(s)
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else:
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labels = s.split(".")
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if not labels or labels == [""]:
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raise IDNAError("Empty domain")
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if not labels[-1]:
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del labels[-1]
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trailing_dot = True
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for label in labels:
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s = ulabel(label)
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if s:
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result.append(s)
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else:
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raise IDNAError("Empty label")
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if trailing_dot:
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result.append("")
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return ".".join(result)
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