| """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:_]*') |
| # 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*=+\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 = 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] |
| 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) |
