mirror of
https://github.com/NewFuture/DDNS.git
synced 2022-04-19 20:24:44 +00:00
141 lines
3.3 KiB
Python
141 lines
3.3 KiB
Python
# -*- coding: utf-8 -*-
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"""
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cache module
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文件缓存
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"""
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from os import path, stat
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from pickle import dump, load
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from time import time
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from logging import info, debug, warning
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try:
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from collections.abc import MutableMapping
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except ImportError:
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# Python 2 imports
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from collections import MutableMapping
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class Cache(MutableMapping):
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"""
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using file to Cache data as dictionary
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"""
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def __init__(self, path, sync=False):
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self.__data = {}
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self.__filename = path
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self.__sync = sync
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self.__time = time()
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self.__changed = False
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self.load()
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@property
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def time(self):
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"""
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缓存修改时间
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"""
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return self.__time
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def load(self, file=None):
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"""
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load data from path
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"""
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if not file:
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file = self.__filename
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debug('load cache data from %s', file)
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if path.isfile(file):
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with open(self.__filename, 'rb') as data:
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try:
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self.__data = load(data)
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self.__time = stat(file).st_mtime
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return self
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except ValueError:
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pass
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except Exception as e:
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warning(e)
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else:
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info('cache file not exist')
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self.__data = {}
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self.__time = time()
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self.__changed = True
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return self
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def data(self, key=None, default=None):
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"""
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获取当前字典或者制定得键值
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"""
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if self.__sync:
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self.load()
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if key is None:
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return self.__data
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else:
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return self.__data.get(key, default)
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def sync(self):
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"""Sync the write buffer with the cache files and clear the buffer.
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"""
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if self.__changed:
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with open(self.__filename, 'wb') as data:
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dump(self.__data, data)
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debug('save cache data to %s', self.__filename)
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self.__time = time()
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self.__changed = False
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return self
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def close(self):
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"""Sync the write buffer, then close the cache.
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If a closed :class:`FileCache` object's methods are called, a
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:exc:`ValueError` will be raised.
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"""
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self.sync()
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del self.__data
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del self.__filename
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del self.__time
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self.__sync = False
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def __update(self):
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self.__changed = True
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if self.__sync:
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self.sync()
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else:
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self.__time = time()
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def clear(self):
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if self.data() is not None:
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self.__data = {}
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self.__update()
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def __setitem__(self, key, value):
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if self.data(key) != value:
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self.__data[key] = value
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self.__update()
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def __delitem__(self, key):
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if key in self.data():
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del self.__data[key]
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self.__update()
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def __getitem__(self, key):
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return self.data(key)
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def __iter__(self):
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for key in self.data():
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yield key
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def __len__(self):
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return len(self.data())
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def __contains__(self, key):
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return key in self.data()
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def __str__(self):
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return self.data().__str__()
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def __del__(self):
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self.close()
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