132 lines
4.8 KiB
Python
132 lines
4.8 KiB
Python
"""
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General functions for HTML manipulation.
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"""
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import re as _re
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from html.entities import html5 as _html5
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__all__ = ['escape', 'unescape']
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def escape(s, quote=True):
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"""
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Replace special characters "&", "<" and ">" to HTML-safe sequences.
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If the optional flag quote is true (the default), the quotation mark
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characters, both double quote (") and single quote (') characters are also
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translated.
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"""
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s = s.replace("&", "&") # Must be done first!
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s = s.replace("<", "<")
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s = s.replace(">", ">")
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if quote:
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s = s.replace('"', """)
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s = s.replace('\'', "'")
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return s
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# see http://www.w3.org/TR/html5/syntax.html#tokenizing-character-references
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_invalid_charrefs = {
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0x00: '\ufffd', # REPLACEMENT CHARACTER
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0x0d: '\r', # CARRIAGE RETURN
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0x80: '\u20ac', # EURO SIGN
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0x81: '\x81', # <control>
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0x82: '\u201a', # SINGLE LOW-9 QUOTATION MARK
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0x83: '\u0192', # LATIN SMALL LETTER F WITH HOOK
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0x84: '\u201e', # DOUBLE LOW-9 QUOTATION MARK
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0x85: '\u2026', # HORIZONTAL ELLIPSIS
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0x86: '\u2020', # DAGGER
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0x87: '\u2021', # DOUBLE DAGGER
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0x88: '\u02c6', # MODIFIER LETTER CIRCUMFLEX ACCENT
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0x89: '\u2030', # PER MILLE SIGN
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0x8a: '\u0160', # LATIN CAPITAL LETTER S WITH CARON
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0x8b: '\u2039', # SINGLE LEFT-POINTING ANGLE QUOTATION MARK
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0x8c: '\u0152', # LATIN CAPITAL LIGATURE OE
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0x8d: '\x8d', # <control>
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0x8e: '\u017d', # LATIN CAPITAL LETTER Z WITH CARON
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0x8f: '\x8f', # <control>
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0x90: '\x90', # <control>
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0x91: '\u2018', # LEFT SINGLE QUOTATION MARK
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0x92: '\u2019', # RIGHT SINGLE QUOTATION MARK
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0x93: '\u201c', # LEFT DOUBLE QUOTATION MARK
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0x94: '\u201d', # RIGHT DOUBLE QUOTATION MARK
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0x95: '\u2022', # BULLET
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0x96: '\u2013', # EN DASH
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0x97: '\u2014', # EM DASH
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0x98: '\u02dc', # SMALL TILDE
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0x99: '\u2122', # TRADE MARK SIGN
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0x9a: '\u0161', # LATIN SMALL LETTER S WITH CARON
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0x9b: '\u203a', # SINGLE RIGHT-POINTING ANGLE QUOTATION MARK
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0x9c: '\u0153', # LATIN SMALL LIGATURE OE
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0x9d: '\x9d', # <control>
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0x9e: '\u017e', # LATIN SMALL LETTER Z WITH CARON
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0x9f: '\u0178', # LATIN CAPITAL LETTER Y WITH DIAERESIS
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}
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_invalid_codepoints = {
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# 0x0001 to 0x0008
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0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8,
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# 0x000E to 0x001F
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0xe, 0xf, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
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0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
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# 0x007F to 0x009F
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0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a,
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0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96,
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0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
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# 0xFDD0 to 0xFDEF
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0xfdd0, 0xfdd1, 0xfdd2, 0xfdd3, 0xfdd4, 0xfdd5, 0xfdd6, 0xfdd7, 0xfdd8,
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0xfdd9, 0xfdda, 0xfddb, 0xfddc, 0xfddd, 0xfdde, 0xfddf, 0xfde0, 0xfde1,
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0xfde2, 0xfde3, 0xfde4, 0xfde5, 0xfde6, 0xfde7, 0xfde8, 0xfde9, 0xfdea,
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0xfdeb, 0xfdec, 0xfded, 0xfdee, 0xfdef,
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# others
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0xb, 0xfffe, 0xffff, 0x1fffe, 0x1ffff, 0x2fffe, 0x2ffff, 0x3fffe, 0x3ffff,
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0x4fffe, 0x4ffff, 0x5fffe, 0x5ffff, 0x6fffe, 0x6ffff, 0x7fffe, 0x7ffff,
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0x8fffe, 0x8ffff, 0x9fffe, 0x9ffff, 0xafffe, 0xaffff, 0xbfffe, 0xbffff,
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0xcfffe, 0xcffff, 0xdfffe, 0xdffff, 0xefffe, 0xeffff, 0xffffe, 0xfffff,
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0x10fffe, 0x10ffff
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}
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def _replace_charref(s):
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s = s.group(1)
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if s[0] == '#':
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# numeric charref
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if s[1] in 'xX':
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num = int(s[2:].rstrip(';'), 16)
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else:
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num = int(s[1:].rstrip(';'))
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if num in _invalid_charrefs:
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return _invalid_charrefs[num]
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if 0xD800 <= num <= 0xDFFF or num > 0x10FFFF:
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return '\uFFFD'
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if num in _invalid_codepoints:
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return ''
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return chr(num)
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else:
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# named charref
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if s in _html5:
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return _html5[s]
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# find the longest matching name (as defined by the standard)
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for x in range(len(s)-1, 1, -1):
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if s[:x] in _html5:
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return _html5[s[:x]] + s[x:]
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else:
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return '&' + s
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_charref = _re.compile(r'&(#[0-9]+;?'
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r'|#[xX][0-9a-fA-F]+;?'
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r'|[^\t\n\f <&#;]{1,32};?)')
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def unescape(s):
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"""
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Convert all named and numeric character references (e.g. >, >,
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&x3e;) in the string s to the corresponding unicode characters.
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This function uses the rules defined by the HTML 5 standard
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for both valid and invalid character references, and the list of
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HTML 5 named character references defined in html.entities.html5.
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"""
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if '&' not in s:
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return s
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return _charref.sub(_replace_charref, s)
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