FanFicFare/fanficfare/browsercache/basebrowsercache.py

220 lines
8.4 KiB
Python

import sys
import os
import time
import gzip
import zlib
try:
# py3 only, calls C libraries. CLI
import brotli
except ImportError:
# Calibre doesn't include brotli, so use plugin packaged
# brotlidecpy, which is slower, but pure python
from calibre_plugins.fanficfare_plugin import brotlidecpy as brotli
import pickle
if sys.version_info < (2, 7):
sys.exit('This program requires Python 2.7 or newer.')
elif sys.version_info < (3, 0):
reload(sys) # Reload restores 'hidden' setdefaultencoding method
sys.setdefaultencoding("utf-8")
def pickle_load(f):
return pickle.load(f)
else: # > 3.0
def pickle_load(f):
return pickle.load(f,encoding="bytes")
import logging
logger = logging.getLogger(__name__)
from ..six import ensure_text
# import cProfile
# def do_cprofile(func):
# def profiled_func(*args, **kwargs):
# profile = cProfile.Profile()
# try:
# profile.enable()
# result = func(*args, **kwargs)
# profile.disable()
# return result
# finally:
# profile.print_stats(sort='time')
# return profiled_func
def do_cprofile(func):
def profiled_func(*args, **kwargs):
t=0
try:
t = time.time()
result = func(*args, **kwargs)
t = time.time() - t
return result
finally:
logger.debug("do_cprofile time:%s"%t)
return profiled_func
class BrowserCacheException(Exception):
pass
## difference in seconds between Jan 1 1601 and Jan 1 1970. Chrome
## caches (so far) have kept time stamps as microseconds since
## 1-1-1601 a Windows/Cobol thing.
EPOCH_DIFFERENCE = 11644473600
import datetime
class BaseBrowserCache(object):
"""Base class to read various formats of web browser cache file"""
def __init__(self, cache_dir, age_limit=-1):
"""Constructor for BaseBrowserCache"""
## only ever
if cache_dir is None:
raise BrowserCacheException("BrowserCache must be initialized with a valid browser cache directory path")
self.cache_dir = os.path.realpath(os.path.expanduser(cache_dir))
if not os.path.isdir(self.cache_dir):
raise BrowserCacheException("BrowserCache cache_dir does not exist: '%s (%s)'" %
(cache_dir, self.cache_dir))
self.age_comp_time = 0
if age_limit is None or age_limit == '':
self.age_limit = -1
else:
self.age_limit = float(age_limit)
self.set_age_comp_time()
# switched from namedtuple or class to primitives because it's
# dirt simple and I want to pickle it.
# map of urls -> (cache_key, cache_time)
self.key_mapping = {}
self.mapping_loaded = False
@classmethod
def new_browser_cache(cls, cache_dir, age_limit=-1):
"""Return new instance of this BrowserCache class, or None if supplied directory not the correct cache type"""
cache_dir = os.path.realpath(os.path.expanduser(cache_dir))
if cls.is_cache_dir(cache_dir):
try:
return cls(cache_dir,age_limit=age_limit)
except BrowserCacheException:
return None
return None
# Chromium uses 1601 epoch for... reasons?
def set_age_comp_time(self):
if self.age_limit > 0.0:
## now - age_limit as microseconds since Jan 1, 1601
## for direct comparison with cache values.
self.age_comp_time = int(time.time() - (self.age_limit*3600) + EPOCH_DIFFERENCE)*1000000
## By doing this once, we save a lot of comparisons
## and extra saved data at the risk of using pages
## that would have expired during long download
## sessions.
## just here for ease of applying @do_cprofile
@do_cprofile
def do_map_cache_keys(self):
logger.debug("do_map_cache_keys()")
self.map_cache_keys()
self.mapping_loaded = True
logger.debug("Cached %s entries"%len(self.key_mapping))
def map_cache_keys(self):
"""Scan index file and cache entries to save entries in this cache"""
raise NotImplementedError()
def cache_key_to_url(self,key):
'''
Modern browsers partition cache by domain to avoid leaking information.
'''
key=ensure_text(key)
# chromium examples seen so far:
# _dk_https://fanfiction.net https://fanfiction.net https://www.fanfiction.net/s/13278343/1/The-Timeless-Vault-HP-travel
# _dk_chrome-extension://akiljllkbielkidmammnifcnibaigelm chrome-extension://akiljllkbielkidmammnifcnibaigelm https://www.fanfiction.net/s/13278343/3/The-Timeless-Vault-HP-travel
# 1610476847265546/_dk_https://fanfiction.net https://fanfiction.net https://www.fanfiction.net/s/13791057/1/A-Yule-Ball-Changes?__cf_chl_jschl_tk__=c80be......
return key.split(' ')[-1]
## should priority be given to keeping any particular domain cache?
def minimal_url(self,url):
'''
ONLY tested with fanfiction.net so far.
Will need to split into separate functions for add and
get--FireFox domain keys different.
'''
url=ensure_text(url)
url = url.split('?')[0]
if 'www.fanfiction.net/s/' in url:
# remove title too.
url = '/'.join(url.split('/')[:6])+'/'
return url
def add_key_mapping(self,cache_url,key,cached_time=None):
'''
ONLY used with fanfiction.net so far.
'''
if self.age_comp_time > cached_time:
return
if 'fanfiction.net/' in cache_url:
minurl = self.minimal_url(self.cache_key_to_url(cache_url))
# logger.debug("add:\n%s\n%s\n%s\n%s"%(cache_url,minurl,key,self.make_datetime(cached_time)))
# if '13425439/4/' in cache_url:
# logger.debug("add:\nurl:%s\nminurl:%s\nkey:%s\ncached_time:%s\ndatetime:%s\nnow:%s"%(cache_url,minurl,key,cached_time,self.make_datetime(cached_time),time.gmtime()))
(existing_key,existing_time) = self.key_mapping.get(minurl,(None,None))
if( existing_key is None
or existing_time is None
or existing_time < cached_time ):
# logger.debug("replacing existing:%s < %s"%(existing_key and self.make_datetime(existing_time),self.make_datetime(cached_time)))
self.key_mapping[minurl]=(key,cached_time)
def get_key_mapping(self,url):
# logger.debug("get_key_mapping:%s"%url)
## on demamand map loading now.
## browser_cache is shared between configurations
## XXX Needs some locking if multi-threading implemented.
if not self.mapping_loaded:
self.do_map_cache_keys()
return self.key_mapping.get(self.minimal_url(url),(None,None))[0]
def get_data(self, url):
# logger.debug("\n\n===================================================\n\nurl:%s\n%s"%(url,self.minimal_url(url)))
key = self.get_key_mapping(self.minimal_url(url))
# logger.debug("key:%s"%key)
if key:
return self.get_data_key(key)
else:
return None
def get_data_key(self,url):
""" Return decoded data for specified key (a URL string) or None """
return None
@staticmethod
def is_cache_dir(cache_dir):
return os.path.isdir(cache_dir) # This method only makes sense when overridden
def make_datetime(self,i):
return datetime.datetime(1601, 1, 1) + datetime.timedelta(microseconds=i)
def load_cache(self,filename=None):
logger.debug("load browser cache mappings(%s)"%(filename or self.filename))
with open(filename or self.filename,'rb') as jin:
self.key_mapping = pickle_load(jin)
# logger.debug(self.basic_cache.keys())
self.mapping_loaded = True
def save_cache(self,filename=None):
with open(filename or self.filename,'wb') as jout:
pickle.dump(self.key_mapping,jout,protocol=2)
logger.debug("save browser cache mappings(%s)"%(filename or self.filename))
def decompress(self, encoding, data):
encoding = ensure_text(encoding)
if encoding == 'gzip':
return gzip.decompress(data)
elif encoding == 'br':
return brotli.decompress(data)
elif encoding == 'deflate':
return zlib.decompress(data)
return data