Commit 037912ee authored by Link Mauve's avatar Link Mauve

util.cache: New module handling both in-memory and on-file system caching.

parent 769bc6d3
......@@ -13,3 +13,5 @@
from slixmpp.util.misc_ops import bytes, unicode, hashes, hash, \
num_to_bytes, bytes_to_num, quote, \
XOR
from slixmpp.util.cache import MemoryCache, MemoryPerJidCache, \
FileSystemCache, FileSystemPerJidCache
"""
Slixmpp: The Slick XMPP Library
Copyright (C) 2018 Emmanuel Gil Peyrot
This file is part of Slixmpp.
See the file LICENSE for copying permission.
"""
import os
import logging
log = logging.getLogger(__name__)
class Cache:
def retrieve(self, key):
raise NotImplementedError
def store(self, key, value):
raise NotImplementedError
class PerJidCache:
def retrieve_by_jid(self, jid, key):
raise NotImplementedError
def store_by_jid(self, jid, key, value):
raise NotImplementedError
class MemoryCache(Cache):
def __init__(self):
self.cache = {}
def retrieve(self, key):
return self.cache.get(key, None)
def store(self, key, value):
self.cache[key] = value
return True
class MemoryPerJidCache(PerJidCache):
def __init__(self):
self.cache = {}
def retrieve_by_jid(self, jid, key):
cache = self.cache.get(jid.bare, None)
if cache is None:
return None
return cache.get(key, None)
def store_by_jid(self, jid, key, value):
cache = self.cache.setdefault(jid.bare, {})
cache[key] = value
return True
class FileSystemStorage:
def __init__(self, encode, decode, binary):
self.encode = encode
self.decode = decode
self.read = 'rb' if binary else 'r'
self.write = 'wb' if binary else 'w'
def _retrieve(self, directory, key):
filename = os.path.join(directory, key.replace('/', '_'))
try:
with open(filename, self.read) as cache_file:
return self.decode(cache_file.read())
except FileNotFoundError:
log.debug('%s not present in cache', key)
except OSError:
log.debug('Failed to read %s from cache:', key, exc_info=True)
return None
def _store(self, directory, key, value):
filename = os.path.join(directory, key.replace('/', '_'))
try:
os.makedirs(directory, exist_ok=True)
with open(filename, self.write) as output:
output.write(self.encode(value))
return True
except OSError:
log.debug('Failed to store %s to cache:', key, exc_info=True)
return False
class FileSystemCache(Cache, FileSystemStorage):
def __init__(self, directory, cache_type, *, encode, decode, binary=False):
FileSystemStorage.__init__(self, encode, decode, binary)
self.base_dir = os.path.join(directory, cache_type)
def retrieve(self, key):
return self._retrieve(self.base_dir, key)
def store(self, key, value):
return self._store(self.base_dir, key, value)
class FileSystemPerJidCache(PerJidCache, FileSystemStorage):
def __init__(self, directory, cache_type, *, encode, decode, binary=False):
FileSystemStorage.__init__(self, encode, decode, binary)
self.base_dir = os.path.join(directory, cache_type)
def retrieve_by_jid(self, jid, key):
directory = os.path.join(self.base_dir, jid.bare)
return self._retrieve(directory, key)
def store_by_jid(self, jid, key, value):
directory = os.path.join(self.base_dir, jid.bare)
return self._store(directory, key, value)
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