| # A parser for XML, using the derived class as static DTD. |
| # Author: Sjoerd Mullender |
| |
| import re |
| import string |
| |
| |
| # Regular expressions used for parsing |
| |
| _S = '[ \t\r\n]+' |
| _opS = '[ \t\r\n]*' |
| _Name = '[a-zA-Z_:][-a-zA-Z0-9._:]*' |
| interesting = re.compile('[&<]') |
| incomplete = re.compile('&(' + _Name + '|#[0-9]*|#x[0-9a-fA-F]*)?|' |
| '<([a-zA-Z_:][^<>]*|' |
| '/([a-zA-Z_:][^<>]*)?|' |
| '![^<>]*|' |
| '\?[^<>]*)?') |
| |
| ref = re.compile('&(' + _Name + '|#[0-9]+|#x[0-9a-fA-F]+);?') |
| entityref = re.compile('&(?P<name>' + _Name + ')[^-a-zA-Z0-9._:]') |
| charref = re.compile('&#(?P<char>[0-9]+[^0-9]|x[0-9a-fA-F]+[^0-9a-fA-F])') |
| space = re.compile(_S) |
| newline = re.compile('\n') |
| |
| starttagopen = re.compile('<' + _Name) |
| endtagopen = re.compile('</') |
| starttagend = re.compile(_opS + '(?P<slash>/?)>') |
| endbracket = re.compile('>') |
| tagfind = re.compile(_Name) |
| cdataopen = re.compile('<!\[CDATA\[') |
| cdataclose = re.compile('\]\]>') |
| special = re.compile('<!(?P<special>[^<>]*)>') |
| procopen = re.compile('<\?(?P<proc>' + _Name + ')' + _S) |
| procclose = re.compile('\?>') |
| commentopen = re.compile('<!--') |
| commentclose = re.compile('-->') |
| doubledash = re.compile('--') |
| attrfind = re.compile( |
| _S + '(?P<name>' + _Name + ')' |
| '(' + _opS + '=' + _opS + |
| '(?P<value>\'[^\']*\'|"[^"]*"|[-a-zA-Z0-9.:+*%?!()_#=~]+))') |
| |
| |
| # XML parser base class -- find tags and call handler functions. |
| # Usage: p = XMLParser(); p.feed(data); ...; p.close(). |
| # The dtd is defined by deriving a class which defines methods |
| # with special names to handle tags: start_foo and end_foo to handle |
| # <foo> and </foo>, respectively, or do_foo to handle <foo> by itself. |
| # (Tags are converted to lower case for this purpose.) The data |
| # between tags is passed to the parser by calling self.handle_data() |
| # with some data as argument (the data may be split up in arbutrary |
| # chunks). Entity references are passed by calling |
| # self.handle_entityref() with the entity reference as argument. |
| |
| class XMLParser: |
| |
| # Interface -- initialize and reset this instance |
| def __init__(self, verbose=0): |
| self.verbose = verbose |
| self.reset() |
| |
| # Interface -- reset this instance. Loses all unprocessed data |
| def reset(self): |
| self.rawdata = '' |
| self.stack = [] |
| self.lasttag = '???' |
| self.nomoretags = 0 |
| self.literal = 0 |
| self.lineno = 1 |
| |
| # For derived classes only -- enter literal mode (CDATA) till EOF |
| def setnomoretags(self): |
| self.nomoretags = self.literal = 1 |
| |
| # For derived classes only -- enter literal mode (CDATA) |
| def setliteral(self, *args): |
| self.literal = 1 |
| |
| # Interface -- feed some data to the parser. Call this as |
| # often as you want, with as little or as much text as you |
| # want (may include '\n'). (This just saves the text, all the |
| # processing is done by goahead().) |
| def feed(self, data): |
| self.rawdata = self.rawdata + data |
| self.goahead(0) |
| |
| # Interface -- handle the remaining data |
| def close(self): |
| self.goahead(1) |
| |
| # Interface -- translate references |
| def translate_references(self, data): |
| newdata = [] |
| i = 0 |
| while 1: |
| res = ref.search(data, i) |
| if res is None: |
| newdata.append(data[i:]) |
| return string.join(newdata, '') |
| if data[res.end(0) - 1] != ';': |
| self.syntax_error(self.lineno, |
| '; missing after entity/char reference') |
| newdata.append(data[i:res.start(0)]) |
| str = res.group(1) |
| if str[0] == '#': |
| if str[1] == 'x': |
| newdata.append(chr(string.atoi(str[2:], 16))) |
| else: |
| newdata.append(chr(string.atoi(str[1:]))) |
| else: |
| try: |
| newdata.append(self.entitydefs[str]) |
| except KeyError: |
| # can't do it, so keep the entity ref in |
| newdata.append('&' + str + ';') |
| i = res.end(0) |
| |
| # 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: |
| if self.nomoretags: |
| data = rawdata[i:n] |
| self.handle_data(data) |
| self.lineno = self.lineno + string.count(data, '\n') |
| i = n |
| break |
| res = interesting.search(rawdata, i) |
| if res: |
| j = res.start(0) |
| else: |
| j = n |
| if i < j: |
| data = rawdata[i:j] |
| self.handle_data(data) |
| self.lineno = self.lineno + string.count(data, '\n') |
| i = j |
| if i == n: break |
| if rawdata[i] == '<': |
| if starttagopen.match(rawdata, i): |
| if self.literal: |
| data = rawdata[i] |
| self.handle_data(data) |
| self.lineno = self.lineno + string.count(data, '\n') |
| i = i+1 |
| continue |
| k = self.parse_starttag(i) |
| if k < 0: break |
| self.lineno = self.lineno + string.count(rawdata[i:k], '\n') |
| i = k |
| continue |
| if endtagopen.match(rawdata, i): |
| k = self.parse_endtag(i) |
| if k < 0: break |
| self.lineno = self.lineno + string.count(rawdata[i:k], '\n') |
| i = k |
| self.literal = 0 |
| continue |
| if commentopen.match(rawdata, i): |
| if self.literal: |
| data = rawdata[i] |
| self.handle_data(data) |
| self.lineno = self.lineno + string.count(data, '\n') |
| i = i+1 |
| continue |
| k = self.parse_comment(i) |
| if k < 0: break |
| self.lineno = self.lineno + string.count(rawdata[i:k], '\n') |
| i = k |
| continue |
| if cdataopen.match(rawdata, i): |
| k = self.parse_cdata(i) |
| if k < 0: break |
| self.lineno = self.lineno + string.count(rawdata[i:i], '\n') |
| i = k |
| continue |
| res = procopen.match(rawdata, i) |
| if res: |
| k = self.parse_proc(i, res) |
| if k < 0: break |
| self.lineno = self.lineno + string.count(rawdata[i:k], '\n') |
| i = k |
| continue |
| res = special.match(rawdata, i) |
| if res: |
| if self.literal: |
| data = rawdata[i] |
| self.handle_data(data) |
| self.lineno = self.lineno + string.count(data, '\n') |
| i = i+1 |
| continue |
| self.handle_special(res.group('special')) |
| self.lineno = self.lineno + string.count(res.group(0), '\n') |
| i = res.end(0) |
| continue |
| elif rawdata[i] == '&': |
| res = charref.match(rawdata, i) |
| if res is not None: |
| i = res.end(0) |
| if rawdata[i-1] != ';': |
| self.syntax_error(self.lineno, '; missing in charref') |
| i = i-1 |
| self.handle_charref(res.group('char')[:-1]) |
| self.lineno = self.lineno + string.count(res.group(0), '\n') |
| continue |
| res = entityref.match(rawdata, i) |
| if res is not None: |
| i = res.end(0) |
| if rawdata[i-1] != ';': |
| self.syntax_error(self.lineno, '; missing in entityref') |
| i = i-1 |
| self.handle_entityref(res.group('name')) |
| self.lineno = self.lineno + string.count(res.group(0), '\n') |
| continue |
| else: |
| raise RuntimeError, 'neither < nor & ??' |
| # We get here only if incomplete matches but |
| # nothing else |
| res = incomplete.match(rawdata, i) |
| if not res: |
| data = rawdata[i] |
| self.handle_data(data) |
| self.lineno = self.lineno + string.count(data, '\n') |
| i = i+1 |
| continue |
| j = res.end(0) |
| if j == n: |
| break # Really incomplete |
| self.syntax_error(self.lineno, 'bogus < or &') |
| data = res.group(0) |
| self.handle_data(data) |
| self.lineno = self.lineno + string.count(data, '\n') |
| i = j |
| # end while |
| if end and i < n: |
| data = rawdata[i:n] |
| self.handle_data(data) |
| self.lineno = self.lineno + string.count(data, '\n') |
| i = n |
| self.rawdata = rawdata[i:] |
| # XXX if end: check for empty stack |
| |
| # Internal -- parse comment, return length or -1 if not terminated |
| def parse_comment(self, i): |
| rawdata = self.rawdata |
| if rawdata[i:i+4] <> '<!--': |
| raise RuntimeError, 'unexpected call to handle_comment' |
| res = commentclose.search(rawdata, i+4) |
| if not res: |
| return -1 |
| # doubledash search will succeed because it's a subset of commentclose |
| if doubledash.search(rawdata, i+4).start(0) < res.start(0): |
| self.syntax_error(self.lineno, "`--' inside comment") |
| self.handle_comment(rawdata[i+4: res.start(0)]) |
| return res.end(0) |
| |
| # Internal -- handle CDATA tag, return lenth or -1 if not terminated |
| def parse_cdata(self, i): |
| rawdata = self.rawdata |
| if rawdata[i:i+9] <> '<![CDATA[': |
| raise RuntimeError, 'unexpected call to handle_cdata' |
| res = cdataclose.search(rawdata, i+9) |
| if not res: |
| return -1 |
| self.handle_cdata(rawdata[i+9:res.start(0)]) |
| return res.end(0) |
| |
| def parse_proc(self, i, res): |
| rawdata = self.rawdata |
| if not res: |
| raise RuntimeError, 'unexpected call to parse_proc' |
| name = res.group('proc') |
| res = procclose.search(rawdata, res.end(0)) |
| if not res: |
| return -1 |
| self.handle_proc(name, rawdata[res.pos:res.start(0)]) |
| return res.end(0) |
| |
| # Internal -- handle starttag, return length or -1 if not terminated |
| def parse_starttag(self, i): |
| rawdata = self.rawdata |
| # i points to start of tag |
| end = endbracket.search(rawdata, i+1) |
| if not end: |
| return -1 |
| j = end.start(0) |
| # Now parse the data between i+1 and j into a tag and attrs |
| attrdict = {} |
| res = tagfind.match(rawdata, i+1) |
| if not res: |
| raise RuntimeError, 'unexpected call to parse_starttag' |
| k = res.end(0) |
| tag = res.group(0) |
| if hasattr(self, tag + '_attributes'): |
| attrlist = getattr(self, tag + '_attributes') |
| else: |
| attrlist = None |
| self.lasttag = tag |
| while k < j: |
| res = attrfind.match(rawdata, k) |
| if not res: break |
| attrname, attrvalue = res.group('name', 'value') |
| if attrvalue is None: |
| self.syntax_error(self.lineno, 'no attribute value specified') |
| attrvalue = attrname |
| elif attrvalue[:1] == "'" == attrvalue[-1:] or \ |
| attrvalue[:1] == '"' == attrvalue[-1:]: |
| attrvalue = attrvalue[1:-1] |
| else: |
| self.syntax_error(self.lineno, 'attribute value not quoted') |
| # XXXX are attribute names case sensitive? |
| attrname = string.lower(attrname) |
| if attrlist is not None and attrname not in attrlist: |
| self.syntax_error(self.lineno, |
| 'unknown attribute %s of element %s' % |
| (attrname, tag)) |
| if attrdict.has_key(attrname): |
| self.syntax_error(self.lineno, 'attribute specified twice') |
| attrdict[attrname] = self.translate_references(attrvalue) |
| k = res.end(0) |
| res = starttagend.match(rawdata, k) |
| if not res: |
| self.syntax_error(self.lineno, 'garbage in start tag') |
| self.finish_starttag(tag, attrdict) |
| if res and res.group('slash') == '/': |
| self.finish_endtag(tag) |
| return end.end(0) |
| |
| # Internal -- parse endtag |
| def parse_endtag(self, i): |
| rawdata = self.rawdata |
| end = endbracket.search(rawdata, i+1) |
| if not end: |
| return -1 |
| res = tagfind.match(rawdata, i+2) |
| if not res: |
| self.syntax_error(self.lineno, 'no name specified in end tag') |
| tag = '' |
| k = i+2 |
| else: |
| tag = res.group(0) |
| k = res.end(0) |
| if k != end.start(0): |
| # check that there is only white space at end of tag |
| res = space.match(rawdata, k) |
| if res is None or res.end(0) != end.start(0): |
| self.syntax_error(self.lineno, 'garbage in end tag') |
| self.finish_endtag(tag) |
| return end.end(0) |
| |
| # Internal -- finish processing of start tag |
| # Return -1 for unknown tag, 1 for balanced tag |
| def finish_starttag(self, tag, attrs): |
| self.stack.append(tag) |
| try: |
| method = getattr(self, 'start_' + tag) |
| except AttributeError: |
| self.unknown_starttag(tag, attrs) |
| return -1 |
| else: |
| self.handle_starttag(tag, method, attrs) |
| return 1 |
| |
| # Internal -- finish processing of end tag |
| def finish_endtag(self, tag): |
| if not tag: |
| found = len(self.stack) - 1 |
| if found < 0: |
| self.unknown_endtag(tag) |
| return |
| else: |
| if tag not in self.stack: |
| try: |
| method = getattr(self, 'end_' + tag) |
| except AttributeError: |
| self.unknown_endtag(tag) |
| return |
| found = len(self.stack) |
| for i in range(found): |
| if self.stack[i] == tag: found = i |
| while len(self.stack) > found: |
| tag = self.stack[-1] |
| try: |
| method = getattr(self, 'end_' + tag) |
| except AttributeError: |
| method = None |
| if method: |
| self.handle_endtag(tag, method) |
| else: |
| self.unknown_endtag(tag) |
| del self.stack[-1] |
| |
| # Overridable -- handle start tag |
| def handle_starttag(self, tag, method, attrs): |
| method(attrs) |
| |
| # Overridable -- handle end tag |
| def handle_endtag(self, tag, method): |
| method() |
| |
| # Example -- handle character reference, no need to override |
| def handle_charref(self, name): |
| try: |
| if name[0] == 'x': |
| n = string.atoi(name[1:], 16) |
| else: |
| n = string.atoi(name) |
| except string.atoi_error: |
| self.unknown_charref(name) |
| return |
| if not 0 <= n <= 255: |
| self.unknown_charref(name) |
| return |
| self.handle_data(chr(n)) |
| |
| # Definition of entities -- derived classes may override |
| entitydefs = \ |
| {'lt': '<', 'gt': '>', 'amp': '&', 'quot': '"', 'apos': '\''} |
| |
| # Example -- handle entity reference, no need to override |
| def handle_entityref(self, name): |
| table = self.entitydefs |
| if table.has_key(name): |
| self.handle_data(table[name]) |
| else: |
| self.unknown_entityref(name) |
| return |
| |
| # Example -- handle data, should be overridden |
| def handle_data(self, data): |
| pass |
| |
| # Example -- handle cdata, could be overridden |
| def handle_cdata(self, data): |
| pass |
| |
| # Example -- handle comment, could be overridden |
| def handle_comment(self, data): |
| pass |
| |
| # Example -- handle processing instructions, could be overridden |
| def handle_proc(self, name, data): |
| pass |
| |
| # Example -- handle special instructions, could be overridden |
| def handle_special(self, data): |
| pass |
| |
| # Example -- handle relatively harmless syntax errors, could be overridden |
| def syntax_error(self, lineno, message): |
| raise RuntimeError, 'Syntax error at line %d: %s' % (lineno, message) |
| |
| # To be overridden -- handlers for unknown objects |
| def unknown_starttag(self, tag, attrs): pass |
| def unknown_endtag(self, tag): pass |
| def unknown_charref(self, ref): pass |
| def unknown_entityref(self, ref): pass |
| |
| |
| class TestXMLParser(XMLParser): |
| |
| def __init__(self, verbose=0): |
| self.testdata = "" |
| XMLParser.__init__(self, verbose) |
| |
| def handle_data(self, data): |
| self.testdata = self.testdata + data |
| if len(`self.testdata`) >= 70: |
| self.flush() |
| |
| def flush(self): |
| data = self.testdata |
| if data: |
| self.testdata = "" |
| print 'data:', `data` |
| |
| def handle_cdata(self, data): |
| self.flush() |
| print 'cdata:', `data` |
| |
| def handle_proc(self, name, data): |
| self.flush() |
| print 'processing:',name,`data` |
| |
| def handle_special(self, data): |
| self.flush() |
| print 'special:',`data` |
| |
| def handle_comment(self, data): |
| self.flush() |
| r = `data` |
| if len(r) > 68: |
| r = r[:32] + '...' + r[-32:] |
| print 'comment:', r |
| |
| def syntax_error(self, lineno, message): |
| print 'error at line %d:' % lineno, message |
| |
| def unknown_starttag(self, tag, attrs): |
| self.flush() |
| if not attrs: |
| print 'start tag: <' + tag + '>' |
| else: |
| print 'start tag: <' + tag, |
| for name, value in attrs: |
| print name + '=' + '"' + value + '"', |
| print '>' |
| |
| def unknown_endtag(self, tag): |
| self.flush() |
| print 'end tag: </' + tag + '>' |
| |
| def unknown_entityref(self, ref): |
| self.flush() |
| print '*** unknown entity ref: &' + ref + ';' |
| |
| def unknown_charref(self, ref): |
| self.flush() |
| print '*** unknown char ref: &#' + ref + ';' |
| |
| def close(self): |
| XMLParser.close(self) |
| self.flush() |
| |
| def test(args = None): |
| import sys |
| |
| if not args: |
| args = sys.argv[1:] |
| |
| if args and args[0] == '-s': |
| args = args[1:] |
| klass = XMLParser |
| else: |
| klass = TestXMLParser |
| |
| if args: |
| file = args[0] |
| else: |
| file = 'test.xml' |
| |
| if file == '-': |
| f = sys.stdin |
| else: |
| try: |
| f = open(file, 'r') |
| except IOError, msg: |
| print file, ":", msg |
| sys.exit(1) |
| |
| data = f.read() |
| if f is not sys.stdin: |
| f.close() |
| |
| x = klass() |
| for c in data: |
| x.feed(c) |
| x.close() |
| |
| |
| if __name__ == '__main__': |
| test() |
| |