128 lines
4.7 KiB
Python
128 lines
4.7 KiB
Python
#!/usr/bin/env python2
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# -*- coding: utf-8 -*-
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# SAT: a jabber client
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# Copyright (C) 2009-2017 Jérôme Poisson (goffi@goffi.org)
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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 Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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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 Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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from sat.core.log import getLogger
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log = getLogger(__name__)
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from sat.tools.common import regex
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from sat.core import exceptions
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from sat.core.constants import Const as C
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import cPickle as pickle
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import mimetypes
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import os.path
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import time
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class Cache(object):
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"""generic file caching"""
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def __init__(self, host, profile=None):
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host = host
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self.profile = profile
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self.cache_dir = os.path.join(
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host.memory.getConfig('', 'local_dir'),
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C.CACHE_DIR,
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regex.pathEscape(profile or ''))
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if not os.path.exists(self.cache_dir):
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os.makedirs(self.cache_dir)
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def getPath(self, filename):
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"""return cached file URL
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@param filename(unicode): cached file name (cache data or actual file)
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"""
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if not filename or u'/' in filename:
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log.error(u"invalid char found in file name, hack attempt? name:{}".format(filename))
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raise exceptions.DataError(u"Invalid char found")
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return os.path.join(self.cache_dir, filename)
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def getFilePath(self, uid):
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"""retrieve absolute path to file
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@param uid(unicode): unique identifier of file
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@return (unicode, None): absolute path to cached file
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None if file is not in cache (or cache is invalid)
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"""
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uid = uid.strip()
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if not uid:
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return None
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cache_url = self.getPath(uid)
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if not os.path.exists(cache_url):
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return None
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try:
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with open(cache_url, 'rb') as f:
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cache_data = pickle.load(f)
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except IOError:
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log.warning(u"can't read cache at {}".format(cache_url))
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return None
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except pickle.UnpicklingError:
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log.warning(u'invalid cache found at {}'.format(cache_url))
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return None
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try:
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eol = cache_data['eol']
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except KeyError:
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log.warning(u'no End Of Life found for cached file {}'.format(uid))
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eol = 0
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if eol < time.time():
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log.debug(u"removing expired cache (expired for {}s)".format(
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time.time() - eol))
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return None
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return self.getPath(cache_data['filename'])
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def cacheData(self, source, uid, mime_type=u'', max_age=None, filename=None):
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"""create cache metadata and file object to use for actual data
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@param source(unicode): source of the cache (should be plugin's import_name)
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@param uid(unicode): an identifier of the file which must be unique
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@param mime_type(unicode): MIME type of the file to cache
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it will be used notably to guess file extension
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@param max_age(int, None): maximum age in seconds
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the cache metadata will have an "eol" (end of life)
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None to use default value
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0 to ignore cache (file will be re-downloaded on each access)
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@param filename: if not None, will be used as filename
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else one will be generated from uid and guessed extension
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@return(file): file object opened in write mode
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you have to close it yourself (hint: use with statement)
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"""
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# FIXME: is it needed to use a separate thread?
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# probably not with the little data expected with BoB
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cache_url = self.getPath(uid)
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ext = mimetypes.guess_extension(mime_type, strict=False)
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if ext is None:
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log.warning(u"can't find extension for MIME type {}".format(mime_type))
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ext = '.dump'
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if filename is None:
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filename = uid + ext
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if max_age is None:
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max_age = C.DEFAULT_MAX_AGE
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cache_data = {'source': source,
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'filename': filename,
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'eol': int(time.time()) + max_age,
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'mime_type': mime_type,
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}
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file_path = self.getPath(filename)
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with open(cache_url, 'wb') as f:
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pickle.dump(cache_data, f, protocol=2)
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return open(file_path, 'wb')
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