"""
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)
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