You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
383 lines
13 KiB
383 lines
13 KiB
4 years ago
|
"""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('[&<]')
|
||
|
|
interesting_cdata = re.compile(r'<(/|\Z)')
|
||
|
|
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:_]*')
|
||
|
|
attrfind = re.compile(
|
||
|
|
r'\s*([a-zA-Z_][-.:a-zA-Z_0-9]*)(\s*=\s*'
|
||
|
|
r'(\'[^\']*\'|"[^"]*"|[-a-zA-Z0-9./,:;+*%?!&$\(\)_#=~]*))?')
|
||
|
|
|
||
|
|
locatestarttagend = re.compile(r"""
|
||
|
|
<[a-zA-Z][-.a-zA-Z0-9:_]* # tag name
|
||
|
|
(?:\s+ # whitespace before attribute name
|
||
|
|
(?:[a-zA-Z_][-.:a-zA-Z0-9_]* # attribute name
|
||
|
|
(?:\s*=\s* # value indicator
|
||
|
|
(?:'[^']*' # LITA-enclosed value
|
||
|
|
|\"[^\"]*\" # LIT-enclosed value
|
||
|
|
|[^'\">\s]+ # bare value
|
||
|
|
)
|
||
|
|
)?
|
||
|
|
)
|
||
|
|
)*
|
||
|
|
\s* # trailing whitespace
|
||
|
|
""", re.VERBOSE)
|
||
|
|
endendtag = re.compile('>')
|
||
|
|
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
|
||
|
|
markupbase.ParserBase.reset(self)
|
||
|
|
|
||
|
|
def feed(self, data):
|
||
|
|
"""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):
|
||
|
|
self.interesting = interesting_cdata
|
||
|
|
|
||
|
|
def clear_cdata_mode(self):
|
||
|
|
self.interesting = interesting_normal
|
||
|
|
|
||
|
|
# 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:
|
||
|
|
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_declaration(i)
|
||
|
|
elif (i + 1) < n:
|
||
|
|
self.handle_data("<")
|
||
|
|
k = i + 1
|
||
|
|
else:
|
||
|
|
break
|
||
|
|
if k < 0:
|
||
|
|
if end:
|
||
|
|
self.error("EOF in middle of construct")
|
||
|
|
break
|
||
|
|
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:
|
||
|
|
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:
|
||
|
|
self.handle_data(rawdata[i:n])
|
||
|
|
i = self.updatepos(i, n)
|
||
|
|
self.rawdata = rawdata[i:]
|
||
|
|
|
||
|
|
# Internal -- parse comment, return end or -1 if not terminated
|
||
|
|
def parse_comment(self, i, report=1):
|
||
|
|
rawdata = self.rawdata
|
||
|
|
assert rawdata[i:i+4] == '<!--', 'unexpected call to parse_comment()'
|
||
|
|
match = commentclose.search(rawdata, i+4)
|
||
|
|
if not match:
|
||
|
|
return -1
|
||
|
|
if report:
|
||
|
|
j = match.start()
|
||
|
|
self.handle_comment(rawdata[i+4: j])
|
||
|
|
j = match.end()
|
||
|
|
return j
|
||
|
|
|
||
|
|
# 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]
|
||
|
|
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.error("junk characters in start tag: %s"
|
||
|
|
% `rawdata[k:endpos][:20]`)
|
||
|
|
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()
|
||
|
|
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
|
||
|
|
self.updatepos(i, j)
|
||
|
|
self.error("malformed start tag")
|
||
|
|
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
|
||
|
|
j = match.end()
|
||
|
|
match = endtagfind.match(rawdata, i) # </ + tag + >
|
||
|
|
if not match:
|
||
|
|
self.error("bad end tag: %s" % `rawdata[i:j]`)
|
||
|
|
tag = match.group(1)
|
||
|
|
self.handle_endtag(tag.lower())
|
||
|
|
self.clear_cdata_mode()
|
||
|
|
return j
|
||
|
|
|
||
|
|
# 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):
|
||
|
|
self.error("unknown declaration: " + `data`)
|
||
|
|
|
||
|
|
# Internal -- helper to remove special character quoting
|
||
|
|
def unescape(self, s):
|
||
|
|
if '&' not in s:
|
||
|
|
return s
|
||
|
|
s = s.replace("<", "<")
|
||
|
|
s = s.replace(">", ">")
|
||
|
|
s = s.replace("'", "'")
|
||
|
|
s = s.replace(""", '"')
|
||
|
|
s = s.replace("&", "&") # Must be last
|
||
|
|
return s
|