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