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Diffstat (limited to 'lib/python2.7/HTMLParser.py')
| -rw-r--r-- | lib/python2.7/HTMLParser.py | 472 |
1 files changed, 472 insertions, 0 deletions
diff --git a/lib/python2.7/HTMLParser.py b/lib/python2.7/HTMLParser.py new file mode 100644 index 0000000..b336a4c --- /dev/null +++ b/lib/python2.7/HTMLParser.py @@ -0,0 +1,472 @@ +"""A parser for HTML and XHTML.""" + +# This file is based on sgmllib.py, but the API is slightly different. + +# XXX There should be a way to distinguish between PCDATA (parsed +# character data -- the normal case), RCDATA (replaceable character +# data -- only char and entity references and end tags are special) +# and CDATA (character data -- only end tags are special). + + +import markupbase +import re + +# Regular expressions used for parsing + +interesting_normal = re.compile('[&<]') +incomplete = re.compile('&[a-zA-Z#]') + +entityref = re.compile('&([a-zA-Z][-.a-zA-Z0-9]*)[^a-zA-Z0-9]') +charref = re.compile('&#(?:[0-9]+|[xX][0-9a-fA-F]+)[^0-9a-fA-F]') + +starttagopen = re.compile('<[a-zA-Z]') +piclose = re.compile('>') +commentclose = re.compile(r'--\s*>') +tagfind = re.compile('([a-zA-Z][-.a-zA-Z0-9:_]*)(?:\s|/(?!>))*') +# see http://www.w3.org/TR/html5/tokenization.html#tag-open-state +# and http://www.w3.org/TR/html5/tokenization.html#tag-name-state +tagfind_tolerant = re.compile('[a-zA-Z][^\t\n\r\f />\x00]*') + +attrfind = re.compile( + r'((?<=[\'"\s/])[^\s/>][^\s/=>]*)(\s*=+\s*' + r'(\'[^\']*\'|"[^"]*"|(?![\'"])[^>\s]*))?(?:\s|/(?!>))*') + +locatestarttagend = re.compile(r""" + <[a-zA-Z][-.a-zA-Z0-9:_]* # tag name + (?:[\s/]* # optional whitespace before attribute name + (?:(?<=['"\s/])[^\s/>][^\s/=>]* # attribute name + (?:\s*=+\s* # value indicator + (?:'[^']*' # LITA-enclosed value + |"[^"]*" # LIT-enclosed value + |(?!['"])[^>\s]* # bare value + ) + )?(?:\s|/(?!>))* + )* + )? + \s* # trailing whitespace +""", re.VERBOSE) +endendtag = re.compile('>') +# the HTML 5 spec, section 8.1.2.2, doesn't allow spaces between +# </ and the tag name, so maybe this should be fixed +endtagfind = re.compile('</\s*([a-zA-Z][-.a-zA-Z0-9:_]*)\s*>') + + +class HTMLParseError(Exception): + """Exception raised for all parse errors.""" + + def __init__(self, msg, position=(None, None)): + assert msg + self.msg = msg + self.lineno = position[0] + self.offset = position[1] + + def __str__(self): + result = self.msg + if self.lineno is not None: + result = result + ", at line %d" % self.lineno + if self.offset is not None: + result = result + ", column %d" % (self.offset + 1) + return result + + +class HTMLParser(markupbase.ParserBase): + """Find tags and other markup and call handler functions. + + Usage: + p = HTMLParser() + p.feed(data) + ... + p.close() + + Start tags are handled by calling self.handle_starttag() or + self.handle_startendtag(); end tags by self.handle_endtag(). The + data between tags is passed from the parser to the derived class + by calling self.handle_data() with the data as argument (the data + may be split up in arbitrary chunks). Entity references are + passed by calling self.handle_entityref() with the entity + reference as the argument. Numeric character references are + passed to self.handle_charref() with the string containing the + reference as the argument. + """ + + CDATA_CONTENT_ELEMENTS = ("script", "style") + + + def __init__(self): + """Initialize and reset this instance.""" + self.reset() + + def reset(self): + """Reset this instance. Loses all unprocessed data.""" + self.rawdata = '' + self.lasttag = '???' + self.interesting = interesting_normal + self.cdata_elem = None + markupbase.ParserBase.reset(self) + + def feed(self, data): + r"""Feed data to the parser. + + Call this as often as you want, with as little or as much text + as you want (may include '\n'). + """ + self.rawdata = self.rawdata + data + self.goahead(0) + + def close(self): + """Handle any buffered data.""" + self.goahead(1) + + def error(self, message): + raise HTMLParseError(message, self.getpos()) + + __starttag_text = None + + def get_starttag_text(self): + """Return full source of start tag: '<...>'.""" + return self.__starttag_text + + def set_cdata_mode(self, elem): + self.cdata_elem = elem.lower() + self.interesting = re.compile(r'</\s*%s\s*>' % self.cdata_elem, re.I) + + def clear_cdata_mode(self): + self.interesting = interesting_normal + self.cdata_elem = None + + # Internal -- handle data as far as reasonable. May leave state + # and data to be processed by a subsequent call. If 'end' is + # true, force handling all data as if followed by EOF marker. + def goahead(self, end): + rawdata = self.rawdata + i = 0 + n = len(rawdata) + while i < n: + match = self.interesting.search(rawdata, i) # < or & + if match: + j = match.start() + else: + if self.cdata_elem: + break + j = n + if i < j: self.handle_data(rawdata[i:j]) + i = self.updatepos(i, j) + if i == n: break + startswith = rawdata.startswith + if startswith('<', i): + if starttagopen.match(rawdata, i): # < + letter + k = self.parse_starttag(i) + elif startswith("</", i): + k = self.parse_endtag(i) + elif startswith("<!--", i): + k = self.parse_comment(i) + elif startswith("<?", i): + k = self.parse_pi(i) + elif startswith("<!", i): + k = self.parse_html_declaration(i) + elif (i + 1) < n: + self.handle_data("<") + k = i + 1 + else: + break + if k < 0: + if not end: + break + k = rawdata.find('>', i + 1) + if k < 0: + k = rawdata.find('<', i + 1) + if k < 0: + k = i + 1 + else: + k += 1 + self.handle_data(rawdata[i:k]) + i = self.updatepos(i, k) + elif startswith("&#", i): + match = charref.match(rawdata, i) + if match: + name = match.group()[2:-1] + self.handle_charref(name) + k = match.end() + if not startswith(';', k-1): + k = k - 1 + i = self.updatepos(i, k) + continue + else: + if ";" in rawdata[i:]: #bail by consuming &# + self.handle_data(rawdata[0:2]) + i = self.updatepos(i, 2) + break + elif startswith('&', i): + match = entityref.match(rawdata, i) + if match: + name = match.group(1) + self.handle_entityref(name) + k = match.end() + if not startswith(';', k-1): + k = k - 1 + i = self.updatepos(i, k) + continue + match = incomplete.match(rawdata, i) + if match: + # match.group() will contain at least 2 chars + if end and match.group() == rawdata[i:]: + self.error("EOF in middle of entity or char ref") + # incomplete + break + elif (i + 1) < n: + # not the end of the buffer, and can't be confused + # with some other construct + self.handle_data("&") + i = self.updatepos(i, i + 1) + else: + break + else: + assert 0, "interesting.search() lied" + # end while + if end and i < n and not self.cdata_elem: + self.handle_data(rawdata[i:n]) + i = self.updatepos(i, n) + self.rawdata = rawdata[i:] + + # Internal -- parse html declarations, return length or -1 if not terminated + # See w3.org/TR/html5/tokenization.html#markup-declaration-open-state + # See also parse_declaration in _markupbase + def parse_html_declaration(self, i): + rawdata = self.rawdata + if rawdata[i:i+2] != '<!': + self.error('unexpected call to parse_html_declaration()') + if rawdata[i:i+4] == '<!--': + # this case is actually already handled in goahead() + return self.parse_comment(i) + elif rawdata[i:i+3] == '<![': + return self.parse_marked_section(i) + elif rawdata[i:i+9].lower() == '<!doctype': + # find the closing > + gtpos = rawdata.find('>', i+9) + if gtpos == -1: + return -1 + self.handle_decl(rawdata[i+2:gtpos]) + return gtpos+1 + else: + return self.parse_bogus_comment(i) + + # Internal -- parse bogus comment, return length or -1 if not terminated + # see http://www.w3.org/TR/html5/tokenization.html#bogus-comment-state + def parse_bogus_comment(self, i, report=1): + rawdata = self.rawdata + if rawdata[i:i+2] not in ('<!', '</'): + self.error('unexpected call to parse_comment()') + pos = rawdata.find('>', i+2) + if pos == -1: + return -1 + if report: + self.handle_comment(rawdata[i+2:pos]) + return pos + 1 + + # Internal -- parse processing instr, return end or -1 if not terminated + def parse_pi(self, i): + rawdata = self.rawdata + assert rawdata[i:i+2] == '<?', 'unexpected call to parse_pi()' + match = piclose.search(rawdata, i+2) # > + if not match: + return -1 + j = match.start() + self.handle_pi(rawdata[i+2: j]) + j = match.end() + return j + + # Internal -- handle starttag, return end or -1 if not terminated + def parse_starttag(self, i): + self.__starttag_text = None + endpos = self.check_for_whole_start_tag(i) + if endpos < 0: + return endpos + rawdata = self.rawdata + self.__starttag_text = rawdata[i:endpos] + + # Now parse the data between i+1 and j into a tag and attrs + attrs = [] + match = tagfind.match(rawdata, i+1) + assert match, 'unexpected call to parse_starttag()' + k = match.end() + self.lasttag = tag = match.group(1).lower() + + while k < endpos: + m = attrfind.match(rawdata, k) + if not m: + break + attrname, rest, attrvalue = m.group(1, 2, 3) + if not rest: + attrvalue = None + elif attrvalue[:1] == '\'' == attrvalue[-1:] or \ + attrvalue[:1] == '"' == attrvalue[-1:]: + attrvalue = attrvalue[1:-1] + if attrvalue: + attrvalue = self.unescape(attrvalue) + attrs.append((attrname.lower(), attrvalue)) + k = m.end() + + end = rawdata[k:endpos].strip() + if end not in (">", "/>"): + lineno, offset = self.getpos() + if "\n" in self.__starttag_text: + lineno = lineno + self.__starttag_text.count("\n") + offset = len(self.__starttag_text) \ + - self.__starttag_text.rfind("\n") + else: + offset = offset + len(self.__starttag_text) + self.handle_data(rawdata[i:endpos]) + return endpos + if end.endswith('/>'): + # XHTML-style empty tag: <span attr="value" /> + self.handle_startendtag(tag, attrs) + else: + self.handle_starttag(tag, attrs) + if tag in self.CDATA_CONTENT_ELEMENTS: + self.set_cdata_mode(tag) + return endpos + + # Internal -- check to see if we have a complete starttag; return end + # or -1 if incomplete. + def check_for_whole_start_tag(self, i): + rawdata = self.rawdata + m = locatestarttagend.match(rawdata, i) + if m: + j = m.end() + next = rawdata[j:j+1] + if next == ">": + return j + 1 + if next == "/": + if rawdata.startswith("/>", j): + return j + 2 + if rawdata.startswith("/", j): + # buffer boundary + return -1 + # else bogus input + self.updatepos(i, j + 1) + self.error("malformed empty start tag") + if next == "": + # end of input + return -1 + if next in ("abcdefghijklmnopqrstuvwxyz=/" + "ABCDEFGHIJKLMNOPQRSTUVWXYZ"): + # end of input in or before attribute value, or we have the + # '/' from a '/>' ending + return -1 + if j > i: + return j + else: + return i + 1 + raise AssertionError("we should not get here!") + + # Internal -- parse endtag, return end or -1 if incomplete + def parse_endtag(self, i): + rawdata = self.rawdata + assert rawdata[i:i+2] == "</", "unexpected call to parse_endtag" + match = endendtag.search(rawdata, i+1) # > + if not match: + return -1 + gtpos = match.end() + match = endtagfind.match(rawdata, i) # </ + tag + > + if not match: + if self.cdata_elem is not None: + self.handle_data(rawdata[i:gtpos]) + return gtpos + # find the name: w3.org/TR/html5/tokenization.html#tag-name-state + namematch = tagfind_tolerant.match(rawdata, i+2) + if not namematch: + # w3.org/TR/html5/tokenization.html#end-tag-open-state + if rawdata[i:i+3] == '</>': + return i+3 + else: + return self.parse_bogus_comment(i) + tagname = namematch.group().lower() + # consume and ignore other stuff between the name and the > + # Note: this is not 100% correct, since we might have things like + # </tag attr=">">, but looking for > after tha name should cover + # most of the cases and is much simpler + gtpos = rawdata.find('>', namematch.end()) + self.handle_endtag(tagname) + return gtpos+1 + + elem = match.group(1).lower() # script or style + if self.cdata_elem is not None: + if elem != self.cdata_elem: + self.handle_data(rawdata[i:gtpos]) + return gtpos + + self.handle_endtag(elem) + self.clear_cdata_mode() + return gtpos + + # Overridable -- finish processing of start+end tag: <tag.../> + def handle_startendtag(self, tag, attrs): + self.handle_starttag(tag, attrs) + self.handle_endtag(tag) + + # Overridable -- handle start tag + def handle_starttag(self, tag, attrs): + pass + + # Overridable -- handle end tag + def handle_endtag(self, tag): + pass + + # Overridable -- handle character reference + def handle_charref(self, name): + pass + + # Overridable -- handle entity reference + def handle_entityref(self, name): + pass + + # Overridable -- handle data + def handle_data(self, data): + pass + + # Overridable -- handle comment + def handle_comment(self, data): + pass + + # Overridable -- handle declaration + def handle_decl(self, decl): + pass + + # Overridable -- handle processing instruction + def handle_pi(self, data): + pass + + def unknown_decl(self, data): + pass + + # Internal -- helper to remove special character quoting + entitydefs = None + def unescape(self, s): + if '&' not in s: + return s + def replaceEntities(s): + s = s.groups()[0] + try: + if s[0] == "#": + s = s[1:] + if s[0] in ['x','X']: + c = int(s[1:], 16) + else: + c = int(s) + return unichr(c) + except ValueError: + return '&#'+s+';' + else: + # Cannot use name2codepoint directly, because HTMLParser supports apos, + # which is not part of HTML 4 + import htmlentitydefs + if HTMLParser.entitydefs is None: + entitydefs = HTMLParser.entitydefs = {'apos':u"'"} + for k, v in htmlentitydefs.name2codepoint.iteritems(): + entitydefs[k] = unichr(v) + try: + return self.entitydefs[s] + except KeyError: + return '&'+s+';' + + return re.sub(r"&(#?[xX]?(?:[0-9a-fA-F]+|\w{1,8}));", replaceEntities, s) |