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git-svn-id: https://linkchecker.svn.sourceforge.net/svnroot/linkchecker/trunk/linkchecker@1426 e7d03fd6-7b0d-0410-9947-9c21f3af8025
114 lines
3.8 KiB
Python
114 lines
3.8 KiB
Python
# -*- coding: iso-8859-1 -*-
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# Copyright (C) 2000-2004 Bastian Kleineidam
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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"""Fast HTML parser module written in C with the following features:
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1. Reentrant
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As soon as any HTML string data is available, we try to feed it
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to the HTML parser. This means that the parser has to scan possible
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incomplete data, recognizing as much as it can. Incomplete trailing
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data is saved for subsequent callsm, or it is just flushed into the
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output buffer with the flush() function.
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A reset() brings the parser back to its initial state, throwing away all
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buffered data.
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2. Coping with HTML syntax errors
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The parser recognizes as much as it can and passes the rest
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of the data as TEXT tokens.
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The scanner only passes complete recognized HTML syntax elements to
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the parser. Invalid syntax elements are passed as TEXT. This way we do
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not need the bison error recovery.
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Incomplete data is rescanned the next time the parser calls yylex() or
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when it is being flush()ed.
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The following syntax errors will be recognized correctly:
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a) missing quotes around attribute values
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b) "</...>" end tags in script modus
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c) missing ">" in tags
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d) invalid tag names
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e) invalid characters inside tags or tag attributes
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Additionally the parser has the following features:
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a) NULL bytes are changed into spaces
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b) <!-- ... --> inside a <script> or <style> are not treated as
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comments but as DATA
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3. Speed
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The FLEX code has options to generate a large but fast scanner.
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The parser ignores forbidden or unnecessary HTML end tags.
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The parser converts tag and attribute names to lower case for easier
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matching.
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The parser quotes all attribute values.
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Python memory management interface is used.
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"""
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import re
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import htmlentitydefs
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def _resolve_ascii_entity (mo):
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"""Helper function for resolve_entities to resolve one &#XXX;
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entity if it is an ASCII character. Else leave as is.
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Input is a match object with a "num" group matched.
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"""
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# convert to number
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ent = mo.group()
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num = mo.group("num")
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if ent.startswith('&#x'):
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radix = 16
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else:
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radix = 10
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num = int(num, radix)
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# check 7-bit ASCII char range
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if 0<=num<=127:
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return chr(num)
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# not in range
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return ent
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def resolve_ascii_entities (s):
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"""resolve entities in 7-bit ASCII range to eliminate obfuscation"""
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return re.sub(r'(?i)&#x?(?P<num>\d+);', _resolve_ascii_entity, s)
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def _resolve_html_entity (mo):
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"""resolve html entity, helper function for resolve_html_entities"""
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return htmlentitydefs.entitydefs.get(mo.group("entity"), mo.group())
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def resolve_html_entities (s):
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"""resolve html entites in s and return result"""
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return re.sub(r'(?i)&(?P<entity>[a-z]+);', _resolve_html_entity, s)
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def resolve_entities (s):
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"""resolve both html and 7-bit ASCII entites in s and return result"""
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return resolve_html_entities(resolve_ascii_entities(s))
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def strip_quotes (s):
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"""remove possible double or single quotes"""
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if len(s) >= 2 and \
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((s.startswith("'") and s.endswith("'")) or \
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(s.startswith('"') and s.endswith('"'))):
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return s[1:-1]
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return s
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