mirror of
https://github.com/Hopiu/linkchecker.git
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75 lines
2.8 KiB
Python
75 lines
2.8 KiB
Python
# -*- coding: iso-8859-1 -*-
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# Copyright (C) 2006-2012 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 along
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# with this program; if not, write to the Free Software Foundation, Inc.,
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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"""
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Cache robots.txt contents.
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"""
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from .. import robotparser2, configuration, url as urlutil
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from ..containers import LFUCache
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from ..decorators import synchronized
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from ..lock import get_lock
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# lock objects
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cache_lock = get_lock("robots.txt_cache_lock")
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robot_lock = get_lock("robots.txt_robot_lock")
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class RobotsTxt (object):
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"""
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Thread-safe cache of downloaded robots.txt files.
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format: {cache key (string) -> robots.txt content (RobotFileParser)}
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"""
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useragent = str(configuration.UserAgent)
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def __init__ (self):
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"""Initialize per-URL robots.txt cache."""
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# mapping {URL -> parsed robots.txt}
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self.cache = LFUCache(size=100)
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self.hits = self.misses = 0
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self.roboturl_locks = {}
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def allows_url (self, roboturl, url, proxy, user, password, callback=None):
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"""Ask robots.txt allowance."""
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with self.get_lock(roboturl):
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return self._allows_url(roboturl, url, proxy, user, password, callback)
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def _allows_url (self, roboturl, url, proxy, user, password, callback):
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"""Ask robots.txt allowance. Assumes only single thread per robots.txt
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URL calls this function."""
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with cache_lock:
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if roboturl in self.cache:
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self.hits += 1
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rp = self.cache[roboturl]
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return rp.can_fetch(self.useragent, url)
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self.misses += 1
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rp = robotparser2.RobotFileParser(proxy=proxy, user=user,
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password=password)
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rp.set_url(roboturl)
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rp.read()
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if hasattr(callback, '__call__'):
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parts = urlutil.url_split(rp.url)
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host = "%s:%d" % (parts[1], parts[2])
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wait = rp.get_crawldelay(self.useragent)
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callback(host, wait)
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with cache_lock:
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self.cache[roboturl] = rp
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return rp.can_fetch(self.useragent, url)
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@synchronized(robot_lock)
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def get_lock(self, roboturl):
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"""Return lock for robots.txt url."""
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return self.roboturl_locks.setdefault(roboturl, get_lock(roboturl))
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