| """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('[&<]') | |
| interesting_cdata = re.compile(r'<(/|\Z)') | |
| 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:_]*') | |
| attrfind = re.compile( | |
| r'\s*([a-zA-Z_][-.:a-zA-Z_0-9]*)(\s*=\s*' | |
| r'(\'[^\']*\'|"[^"]*"|[^\s"\'=<>`]*))?') | |
| locatestarttagend = re.compile(r""" | |
| <[a-zA-Z][-.a-zA-Z0-9:_]* # tag name | |
| (?:\s+ # whitespace before attribute name | |
| (?:[a-zA-Z_][-.:a-zA-Z0-9_]* # attribute name | |
| (?:\s*=\s* # value indicator | |
| (?:'[^']*' # LITA-enclosed value | |
| |\"[^\"]*\" # LIT-enclosed value | |
| |[^'\">\s]+ # bare value | |
| ) | |
| )? | |
| ) | |
| )* | |
| \s* # trailing whitespace | |
| """, re.VERBOSE) | |
| endendtag = re.compile('>') | |
| 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 | |
| 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): | |
| self.interesting = interesting_cdata | |
| def clear_cdata_mode(self): | |
| self.interesting = interesting_normal | |
| # 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: | |
| 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_declaration(i) | |
| elif (i + 1) < n: | |
| self.handle_data("<") | |
| k = i + 1 | |
| else: | |
| break | |
| if k < 0: | |
| if end: | |
| self.error("EOF in middle of construct") | |
| break | |
| 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: | |
| self.handle_data(rawdata[i:n]) | |
| i = self.updatepos(i, n) | |
| self.rawdata = rawdata[i:] | |
| # 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 = rawdata[i+1:k].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] | |
| 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.error("junk characters in start tag: %r" | |
| % (rawdata[k:endpos][:20],)) | |
| 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() | |
| 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 | |
| self.updatepos(i, j) | |
| self.error("malformed start tag") | |
| 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 | |
| j = match.end() | |
| match = endtagfind.match(rawdata, i) # </ + tag + > | |
| if not match: | |
| self.error("bad end tag: %r" % (rawdata[i:j],)) | |
| tag = match.group(1) | |
| self.handle_endtag(tag.lower()) | |
| self.clear_cdata_mode() | |
| return j | |
| # 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): | |
| self.error("unknown declaration: %r" % (data,)) | |
| # 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) |