cpython/Lib/xmllib.py

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# 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. 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')
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()