--- /dev/null
+# 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()
+
projects / python / commitdiff