396 lines
12 KiB
Python
396 lines
12 KiB
Python
from . import idnadata
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import bisect
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import unicodedata
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import re
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from typing import Union, Optional
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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 = None # type: Optional[str]
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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 not direction in ['R', 'AL', 'AN', 'EN', 'ES', 'CS', 'ET', 'ON', 'BN', 'NSM']:
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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 not direction 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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if not valid_contextj(label, pos):
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raise InvalidCodepointContext('Joiner {} not allowed at position {} in {}'.format(
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_unot(cp_value), pos+1, repr(label)))
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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('Codepoint {} not allowed at position {} in {}'.format(_unot(cp_value), pos+1, repr(label)))
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else:
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raise InvalidCodepoint('Codepoint {} at position {} of {} not allowed'.format(_unot(cp_value), pos+1, repr(label)))
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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
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bisect.bisect_left(uts46data, (code_point, 'Z')) - 1]
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status = uts46row[1]
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replacement = None # type: Optional[str]
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if len(uts46row) == 3:
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replacement = uts46row[2]
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if (status == 'V' or
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(status == 'D' and not transitional) or
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(status == '3' and not std3_rules and replacement is None)):
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output += char
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elif replacement is not None and (status == 'M' or
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(status == '3' and not std3_rules) or
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(status == 'D' and transitional)):
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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(
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_unot(code_point), pos + 1, repr(domain)))
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return unicodedata.normalize('NFC', output)
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def encode(s: Union[str, bytes, bytearray], strict: bool = False, uts46: bool = False, std3_rules: bool = False, transitional: bool = False) -> 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(s: Union[str, bytes, bytearray], strict: bool = False, uts46: bool = False, std3_rules: bool = False) -> 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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