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Diffstat (limited to 'bs4/dammit.py')
| -rw-r--r-- | bs4/dammit.py | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/bs4/dammit.py b/bs4/dammit.py new file mode 100644 index 0000000..75d445e --- /dev/null +++ b/bs4/dammit.py @@ -0,0 +1,412 @@ +"""Beautiful Soup bonus library: Unicode, Dammit + +This class forces XML data into a standard format (usually to UTF-8 or +Unicode). It is heavily based on code from Mark Pilgrim's Universal +Feed Parser. It does not rewrite the XML or HTML to reflect a new +encoding; that's the tree builder's job. +""" + +import codecs +from htmlentitydefs import codepoint2name +import re +import types + +# Autodetects character encodings. Very useful. +# Download from http://chardet.feedparser.org/ +# or 'apt-get install python-chardet' +# or 'easy_install chardet' +try: + import chardet + #import chardet.constants + #chardet.constants._debug = 1 +except ImportError: + chardet = None + +# Available from http://cjkpython.i18n.org/. +try: + import iconv_codec +except ImportError: + pass + + +class EntitySubstitution(object): + + """Substitute XML or HTML entities for the corresponding characters.""" + + def _populate_class_variables(): + lookup = {} + reverse_lookup = {} + characters = [] + for codepoint, name in codepoint2name.items(): + if codepoint == 34: + # There's no point in turning the quotation mark into + # ", unless it happens within an attribute value, which + # is handled elsewhere. + continue; + character = unichr(codepoint) + characters.append(character) + lookup[character] = name + reverse_lookup[name] = character + re_definition = "[%s]" % "".join(characters) + return lookup, reverse_lookup, re.compile(re_definition) + (CHARACTER_TO_HTML_ENTITY, HTML_ENTITY_TO_CHARACTER, + CHARACTER_TO_HTML_ENTITY_RE) = _populate_class_variables() + + + CHARACTER_TO_XML_ENTITY = { + "'" : "apos", + '"' : "quot", + "&" : "amp", + "<" : "lt", + ">" : "gt", + } + + BARE_AMPERSAND_OR_BRACKET = re.compile("([<>]|" + "&(?!#\d+;|#x[0-9a-fA-F]+;|\w+;)" + ")") + + @classmethod + def _substitute_html_entity(cls, matchobj): + entity = cls.CHARACTER_TO_HTML_ENTITY.get(matchobj.group(0)) + return "&%s;" % entity + + @classmethod + def _substitute_xml_entity(cls, matchobj): + """Used with a regular expression to substitute the + appropriate XML entity for an XML special character.""" + entity = cls.CHARACTER_TO_XML_ENTITY[matchobj.group(0)] + return "&%s;" % entity + + @classmethod + def substitute_xml(cls, value, make_quoted_attribute=False): + """Substitute XML entities for special XML characters. + + :param value: A string to be substituted. The less-than sign will + become <, the greater-than sign will become >, and any + ampersands that are not part of an entity defition will + become &. + + :param make_quoted_attribute: If True, then the string will be + quoted, as befits an attribute value. + + Ordinarily, the string will be quoted using double quotes. + + Bob's Bar -> "Bob's Bar" + + If the string contains double quotes, it will be quoted using + single quotes. + + Welcome to "my bar" -> 'Welcome to "my bar"' + + If the string contains both single and double quotes, the + double quotes will be escaped, and the string will be quoted + using double quotes. + + Welcome to "Bob's Bar" -> "Welcome to "Bob's bar" + """ + if make_quoted_attribute: + quote_with = '"' + if '"' in value: + if "'" in value: + # The string contains both single and double + # quotes. Turn the double quotes into + # entities. We quote the double quotes rather than + # the single quotes because the entity name is + # """ whether this is HTML or XML. If we + # quoted the single quotes, we'd have to decide + # between ' and &squot;. + replace_with = """ + value = value.replace('"', replace_with) + else: + # There are double quotes but no single quotes. + # We can use single quotes to quote the attribute. + quote_with = "'" + + # Escape angle brackets, and ampersands that aren't part of + # entities. + value = cls.BARE_AMPERSAND_OR_BRACKET.sub( + cls._substitute_xml_entity, value) + if make_quoted_attribute: + return quote_with + value + quote_with + else: + return value + + @classmethod + def substitute_html(cls, s): + """Replace certain Unicode characters with named HTML entities. + + This differs from data.encode(encoding, 'xmlcharrefreplace') + in that the goal is to make the result more readable (to those + with ASCII displays) rather than to recover from + errors. There's absolutely nothing wrong with a UTF-8 string + containg a LATIN SMALL LETTER E WITH ACUTE, but replacing that + character with "é" will make it more readable to some + people. + """ + return cls.CHARACTER_TO_HTML_ENTITY_RE.sub( + cls._substitute_html_entity, s) + + +class UnicodeDammit: + """A class for detecting the encoding of a *ML document and + converting it to a Unicode string. If the source encoding is + windows-1252, can replace MS smart quotes with their HTML or XML + equivalents.""" + + # This dictionary maps commonly seen values for "charset" in HTML + # meta tags to the corresponding Python codec names. It only covers + # values that aren't in Python's aliases and can't be determined + # by the heuristics in find_codec. + CHARSET_ALIASES = { "macintosh" : "mac-roman", + "x-sjis" : "shift-jis" } + + ENCODINGS_WITH_SMART_QUOTES = [ + "windows-1252", + "iso-8859-1", + "iso-8859-2", + ] + + def __init__(self, markup, override_encodings=[], + smart_quotes_to=None, isHTML=False): + self.declared_html_encoding = None + self.markup, document_encoding, sniffed_encoding = \ + self._detectEncoding(markup, isHTML) + self.smart_quotes_to = smart_quotes_to + self.tried_encodings = [] + if markup == '' or isinstance(markup, unicode): + self.original_encoding = None + self.unicode = unicode(markup) + return + + u = None + for proposed_encoding in ( + override_encodings + [document_encoding, sniffed_encoding]): + if proposed_encoding is not None: + u = self._convert_from(proposed_encoding) + if u: + break + + # If no luck and we have auto-detection library, try that: + if not u and chardet and not isinstance(self.markup, unicode): + u = self._convert_from(chardet.detect(self.markup)['encoding']) + + # As a last resort, try utf-8 and windows-1252: + if not u: + for proposed_encoding in ("utf-8", "windows-1252"): + u = self._convert_from(proposed_encoding) + if u: + break + + self.unicode = u + if not u: self.original_encoding = None + + def _sub_ms_char(self, match): + """Changes a MS smart quote character to an XML or HTML + entity.""" + orig = match.group(1) + sub = self.MS_CHARS.get(orig) + if type(sub) == types.TupleType: + if self.smart_quotes_to == 'xml': + sub = '&#x'.encode() + sub[1].encode() + ';'.encode() + else: + sub = '&'.encode() + sub[0].encode() + ';'.encode() + else: + sub = sub.encode() + return sub + + def _convert_from(self, proposed): + proposed = self.find_codec(proposed) + if not proposed or proposed in self.tried_encodings: + return None + self.tried_encodings.append(proposed) + markup = self.markup + + # Convert smart quotes to HTML if coming from an encoding + # that might have them. + if (self.smart_quotes_to is not None + and proposed.lower() in self.ENCODINGS_WITH_SMART_QUOTES): + smart_quotes_re = "([\x80-\x9f])" + smart_quotes_compiled = re.compile(smart_quotes_re) + markup = smart_quotes_compiled.sub(self._sub_ms_char, markup) + + try: + # print "Trying to convert document to %s" % proposed + u = self._to_unicode(markup, proposed) + self.markup = u + self.original_encoding = proposed + except Exception, e: + # print "That didn't work!" + # print e + return None + #print "Correct encoding: %s" % proposed + return self.markup + + def _to_unicode(self, data, encoding): + '''Given a string and its encoding, decodes the string into Unicode. + %encoding is a string recognized by encodings.aliases''' + + # strip Byte Order Mark (if present) + if (len(data) >= 4) and (data[:2] == '\xfe\xff') \ + and (data[2:4] != '\x00\x00'): + encoding = 'utf-16be' + data = data[2:] + elif (len(data) >= 4) and (data[:2] == '\xff\xfe') \ + and (data[2:4] != '\x00\x00'): + encoding = 'utf-16le' + data = data[2:] + elif data[:3] == '\xef\xbb\xbf': + encoding = 'utf-8' + data = data[3:] + elif data[:4] == '\x00\x00\xfe\xff': + encoding = 'utf-32be' + data = data[4:] + elif data[:4] == '\xff\xfe\x00\x00': + encoding = 'utf-32le' + data = data[4:] + newdata = unicode(data, encoding) + return newdata + + def _detectEncoding(self, xml_data, isHTML=False): + """Given a document, tries to detect its XML encoding.""" + xml_encoding = sniffed_xml_encoding = None + try: + if xml_data[:4] == '\x4c\x6f\xa7\x94': + # EBCDIC + xml_data = self._ebcdic_to_ascii(xml_data) + elif xml_data[:4] == '\x00\x3c\x00\x3f': + # UTF-16BE + sniffed_xml_encoding = 'utf-16be' + xml_data = unicode(xml_data, 'utf-16be').encode('utf-8') + elif (len(xml_data) >= 4) and (xml_data[:2] == '\xfe\xff') \ + and (xml_data[2:4] != '\x00\x00'): + # UTF-16BE with BOM + sniffed_xml_encoding = 'utf-16be' + xml_data = unicode(xml_data[2:], 'utf-16be').encode('utf-8') + elif xml_data[:4] == '\x3c\x00\x3f\x00': + # UTF-16LE + sniffed_xml_encoding = 'utf-16le' + xml_data = unicode(xml_data, 'utf-16le').encode('utf-8') + elif (len(xml_data) >= 4) and (xml_data[:2] == '\xff\xfe') and \ + (xml_data[2:4] != '\x00\x00'): + # UTF-16LE with BOM + sniffed_xml_encoding = 'utf-16le' + xml_data = unicode(xml_data[2:], 'utf-16le').encode('utf-8') + elif xml_data[:4] == '\x00\x00\x00\x3c': + # UTF-32BE + sniffed_xml_encoding = 'utf-32be' + xml_data = unicode(xml_data, 'utf-32be').encode('utf-8') + elif xml_data[:4] == '\x3c\x00\x00\x00': + # UTF-32LE + sniffed_xml_encoding = 'utf-32le' + xml_data = unicode(xml_data, 'utf-32le').encode('utf-8') + elif xml_data[:4] == '\x00\x00\xfe\xff': + # UTF-32BE with BOM + sniffed_xml_encoding = 'utf-32be' + xml_data = unicode(xml_data[4:], 'utf-32be').encode('utf-8') + elif xml_data[:4] == '\xff\xfe\x00\x00': + # UTF-32LE with BOM + sniffed_xml_encoding = 'utf-32le' + xml_data = unicode(xml_data[4:], 'utf-32le').encode('utf-8') + elif xml_data[:3] == '\xef\xbb\xbf': + # UTF-8 with BOM + sniffed_xml_encoding = 'utf-8' + xml_data = unicode(xml_data[3:], 'utf-8').encode('utf-8') + else: + sniffed_xml_encoding = 'ascii' + pass + except: + xml_encoding_match = None + xml_encoding_re = '^<\?.*encoding=[\'"](.*?)[\'"].*\?>'.encode() + xml_encoding_match = re.compile(xml_encoding_re).match(xml_data) + if not xml_encoding_match and isHTML: + meta_re = '<\s*meta[^>]+charset=([^>]*?)[;\'">]'.encode() + regexp = re.compile(meta_re, re.I) + xml_encoding_match = regexp.search(xml_data) + if xml_encoding_match is not None: + xml_encoding = xml_encoding_match.groups()[0].decode( + 'ascii').lower() + if isHTML: + self.declared_html_encoding = xml_encoding + if sniffed_xml_encoding and \ + (xml_encoding in ('iso-10646-ucs-2', 'ucs-2', 'csunicode', + 'iso-10646-ucs-4', 'ucs-4', 'csucs4', + 'utf-16', 'utf-32', 'utf_16', 'utf_32', + 'utf16', 'u16')): + xml_encoding = sniffed_xml_encoding + return xml_data, xml_encoding, sniffed_xml_encoding + + + def find_codec(self, charset): + return self._codec(self.CHARSET_ALIASES.get(charset, charset)) \ + or (charset and self._codec(charset.replace("-", ""))) \ + or (charset and self._codec(charset.replace("-", "_"))) \ + or charset + + def _codec(self, charset): + if not charset: return charset + codec = None + try: + codecs.lookup(charset) + codec = charset + except (LookupError, ValueError): + pass + return codec + + EBCDIC_TO_ASCII_MAP = None + def _ebcdic_to_ascii(self, s): + c = self.__class__ + if not c.EBCDIC_TO_ASCII_MAP: + emap = (0,1,2,3,156,9,134,127,151,141,142,11,12,13,14,15, + 16,17,18,19,157,133,8,135,24,25,146,143,28,29,30,31, + 128,129,130,131,132,10,23,27,136,137,138,139,140,5,6,7, + 144,145,22,147,148,149,150,4,152,153,154,155,20,21,158,26, + 32,160,161,162,163,164,165,166,167,168,91,46,60,40,43,33, + 38,169,170,171,172,173,174,175,176,177,93,36,42,41,59,94, + 45,47,178,179,180,181,182,183,184,185,124,44,37,95,62,63, + 186,187,188,189,190,191,192,193,194,96,58,35,64,39,61,34, + 195,97,98,99,100,101,102,103,104,105,196,197,198,199,200, + 201,202,106,107,108,109,110,111,112,113,114,203,204,205, + 206,207,208,209,126,115,116,117,118,119,120,121,122,210, + 211,212,213,214,215,216,217,218,219,220,221,222,223,224, + 225,226,227,228,229,230,231,123,65,66,67,68,69,70,71,72, + 73,232,233,234,235,236,237,125,74,75,76,77,78,79,80,81, + 82,238,239,240,241,242,243,92,159,83,84,85,86,87,88,89, + 90,244,245,246,247,248,249,48,49,50,51,52,53,54,55,56,57, + 250,251,252,253,254,255) + import string + c.EBCDIC_TO_ASCII_MAP = string.maketrans( \ + ''.join(map(chr, range(256))), ''.join(map(chr, emap))) + return s.translate(c.EBCDIC_TO_ASCII_MAP) + + MS_CHARS = { '\x80' : ('euro', '20AC'), + '\x81' : ' ', + '\x82' : ('sbquo', '201A'), + '\x83' : ('fnof', '192'), + '\x84' : ('bdquo', '201E'), + '\x85' : ('hellip', '2026'), + '\x86' : ('dagger', '2020'), + '\x87' : ('Dagger', '2021'), + '\x88' : ('circ', '2C6'), + '\x89' : ('permil', '2030'), + '\x8A' : ('Scaron', '160'), + '\x8B' : ('lsaquo', '2039'), + '\x8C' : ('OElig', '152'), + '\x8D' : '?', + '\x8E' : ('#x17D', '17D'), + '\x8F' : '?', + '\x90' : '?', + '\x91' : ('lsquo', '2018'), + '\x92' : ('rsquo', '2019'), + '\x93' : ('ldquo', '201C'), + '\x94' : ('rdquo', '201D'), + '\x95' : ('bull', '2022'), + '\x96' : ('ndash', '2013'), + '\x97' : ('mdash', '2014'), + '\x98' : ('tilde', '2DC'), + '\x99' : ('trade', '2122'), + '\x9a' : ('scaron', '161'), + '\x9b' : ('rsaquo', '203A'), + '\x9c' : ('oelig', '153'), + '\x9d' : '?', + '\x9e' : ('#x17E', '17E'), + '\x9f' : ('Yuml', ''),} |