Split Unicode Dammit into a separate library.

1 files changed, 292 insertions, 0 deletions

diff --git a/dammit.py b/dammit.py
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+++ b/dammit.py
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+"""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 Beautiful Soup's job.
+"""
+
+import codecs
+import re
+import types
+
+# Autodetects character encodings.
+# Download from http://chardet.feedparser.org/
+try:
+    import chardet
+#    import chardet.constants
+#    chardet.constants._debug = 1
+except ImportError:
+    chardet = None
+
+# cjkcodecs and iconv_codec make Python know about more character encodings.
+# Both are available from http://cjkpython.i18n.org/
+# They're built in if you use Python 2.4.
+try:
+    import cjkcodecs.aliases
+except ImportError:
+    pass
+try:
+    import iconv_codec
+except ImportError:
+    pass
+
+
+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" }
+
+    def __init__(self, markup, overrideEncodings=[],
+                 smartQuotesTo='xml', isHTML=False):
+        self.declaredHTMLEncoding = None
+        self.markup, documentEncoding, sniffedEncoding = \
+                     self._detectEncoding(markup, isHTML)
+        self.smartQuotesTo = smartQuotesTo
+        self.triedEncodings = []
+        if markup == '' or isinstance(markup, unicode):
+            self.originalEncoding = None
+            self.unicode = unicode(markup)
+            return
+
+        u = None
+        for proposedEncoding in overrideEncodings:
+            u = self._convertFrom(proposedEncoding)
+            if u: break
+        if not u:
+            for proposedEncoding in (documentEncoding, sniffedEncoding):
+                u = self._convertFrom(proposedEncoding)
+                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._convertFrom(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._convertFrom(proposed_encoding)
+                if u: break
+
+        self.unicode = u
+        if not u: self.originalEncoding = None
+
+    def _subMSChar(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.smartQuotesTo == 'xml':
+                sub = '&#x'.encode() + sub[1].encode() + ';'.encode()
+            else:
+                sub = '&'.encode() + sub[0].encode() + ';'.encode()
+        else:
+            sub = sub.encode()
+        return sub
+
+    def _convertFrom(self, proposed):
+        proposed = self.find_codec(proposed)
+        if not proposed or proposed in self.triedEncodings:
+            return None
+        self.triedEncodings.append(proposed)
+        markup = self.markup
+
+        # Convert smart quotes to HTML if coming from an encoding
+        # that might have them.
+        if self.smartQuotesTo and proposed.lower() in("windows-1252",
+                                                      "iso-8859-1",
+                                                      "iso-8859-2"):
+            smart_quotes_re = "([\x80-\x9f])"
+            smart_quotes_compiled = re.compile(smart_quotes_re)
+            markup = smart_quotes_compiled.sub(self._subMSChar, markup)
+
+        try:
+            # print "Trying to convert document to %s" % proposed
+            u = self._toUnicode(markup, proposed)
+            self.markup = u
+            self.originalEncoding = proposed
+        except Exception, e:
+            # print "That didn't work!"
+            # print e
+            return None
+        #print "Correct encoding: %s" % proposed
+        return self.markup
+
+    def _toUnicode(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.declaredHTMLEncoding = 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', ''),}