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