mirror of
https://github.com/moparisthebest/SickRage
synced 2024-12-14 20:12:19 -05:00
205 lines
7.2 KiB
Python
205 lines
7.2 KiB
Python
#!/usr/bin/env python
|
|
#
|
|
# Copyright 2007 Doug Hellmann.
|
|
#
|
|
#
|
|
# All Rights Reserved
|
|
#
|
|
# Permission to use, copy, modify, and distribute this software and
|
|
# its documentation for any purpose and without fee is hereby
|
|
# granted, provided that the above copyright notice appear in all
|
|
# copies and that both that copyright notice and this permission
|
|
# notice appear in supporting documentation, and that the name of Doug
|
|
# Hellmann not be used in advertising or publicity pertaining to
|
|
# distribution of the software without specific, written prior
|
|
# permission.
|
|
#
|
|
# DOUG HELLMANN DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
|
|
# INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
|
|
# NO EVENT SHALL DOUG HELLMANN BE LIABLE FOR ANY SPECIAL, INDIRECT OR
|
|
# CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
|
|
# OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
|
|
# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
|
|
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
#
|
|
|
|
"""
|
|
|
|
"""
|
|
|
|
__module_id__ = "$Id$"
|
|
|
|
#
|
|
# Import system modules
|
|
#
|
|
from feedparser import feedparser
|
|
|
|
import logging
|
|
import time
|
|
|
|
#
|
|
# Import local modules
|
|
#
|
|
|
|
|
|
#
|
|
# Module
|
|
#
|
|
|
|
logger = logging.getLogger('feedcache.cache')
|
|
|
|
|
|
class Cache:
|
|
"""A class to wrap Mark Pilgrim's Universal Feed Parser module
|
|
(http://www.feedparser.org) so that parameters can be used to
|
|
cache the feed results locally instead of fetching the feed every
|
|
time it is requested. Uses both etag and modified times for
|
|
caching.
|
|
"""
|
|
|
|
def __init__(self, storage, timeToLiveSeconds=300, userAgent='feedcache'):
|
|
"""
|
|
Arguments:
|
|
|
|
storage -- Backing store for the cache. It should follow
|
|
the dictionary API, with URLs used as keys. It should
|
|
persist data.
|
|
|
|
timeToLiveSeconds=300 -- The length of time content should
|
|
live in the cache before an update is attempted.
|
|
|
|
userAgent='feedcache' -- User agent string to be used when
|
|
fetching feed contents.
|
|
|
|
"""
|
|
self.storage = storage
|
|
self.time_to_live = timeToLiveSeconds
|
|
self.user_agent = userAgent
|
|
return
|
|
|
|
def purge(self, olderThanSeconds):
|
|
"""Remove cached data from the storage if the data is older than the
|
|
date given. If olderThanSeconds is None, the entire cache is purged.
|
|
"""
|
|
if olderThanSeconds is None:
|
|
logger.debug('purging the entire cache')
|
|
for key in self.storage.keys():
|
|
del self.storage[key]
|
|
else:
|
|
now = time.time()
|
|
# Iterate over the keys and load each item one at a time
|
|
# to avoid having the entire cache loaded into memory
|
|
# at one time.
|
|
for url in self.storage.keys():
|
|
(cached_time, cached_data) = self.storage[url]
|
|
age = now - cached_time
|
|
if age >= olderThanSeconds:
|
|
logger.debug('removing %s with age %d', url, age)
|
|
del self.storage[url]
|
|
return
|
|
|
|
def fetch(self, url, force_update=False, offline=False):
|
|
"""Return the feed at url.
|
|
|
|
url - The URL of the feed.
|
|
|
|
force_update=False - When True, update the cache whether the
|
|
current contents have
|
|
exceeded their time-to-live
|
|
or not.
|
|
|
|
offline=False - When True, only return data from the local
|
|
cache and never access the remote
|
|
URL.
|
|
|
|
If there is data for that feed in the cache already, check
|
|
the expiration date before accessing the server. If the
|
|
cached data has not expired, return it without accessing the
|
|
server.
|
|
|
|
In cases where the server is accessed, check for updates
|
|
before deciding what to return. If the server reports a
|
|
status of 304, the previously cached content is returned.
|
|
|
|
The cache is only updated if the server returns a status of
|
|
200, to avoid holding redirected data in the cache.
|
|
"""
|
|
logger.debug('url="%s"' % url)
|
|
|
|
# Convert the URL to a value we can use
|
|
# as a key for the storage backend.
|
|
key = url
|
|
if isinstance(key, unicode):
|
|
key = key.encode('utf-8')
|
|
|
|
modified = None
|
|
etag = None
|
|
now = time.time()
|
|
|
|
cached_time, cached_content = self.storage.get(key, (None, None))
|
|
|
|
# Offline mode support (no networked requests)
|
|
# so return whatever we found in the storage.
|
|
# If there is nothing in the storage, we'll be returning None.
|
|
if offline:
|
|
logger.debug('offline mode')
|
|
return cached_content
|
|
|
|
# Does the storage contain a version of the data
|
|
# which is older than the time-to-live?
|
|
logger.debug('cache modified time: %s' % str(cached_time))
|
|
if cached_time is not None and not force_update:
|
|
if self.time_to_live:
|
|
age = now - cached_time
|
|
if age <= self.time_to_live:
|
|
logger.debug('cache contents still valid')
|
|
return cached_content
|
|
else:
|
|
logger.debug('cache contents older than TTL')
|
|
else:
|
|
logger.debug('no TTL value')
|
|
|
|
# The cache is out of date, but we have
|
|
# something. Try to use the etag and modified_time
|
|
# values from the cached content.
|
|
etag = cached_content.get('etag')
|
|
modified = cached_content.get('modified')
|
|
logger.debug('cached etag=%s' % etag)
|
|
logger.debug('cached modified=%s' % str(modified))
|
|
else:
|
|
logger.debug('nothing in the cache, or forcing update')
|
|
|
|
# We know we need to fetch, so go ahead and do it.
|
|
logger.debug('fetching...')
|
|
parsed_result = feedparser.parse(url,
|
|
agent=self.user_agent,
|
|
modified=modified,
|
|
etag=etag,
|
|
)
|
|
|
|
status = parsed_result.get('status', None)
|
|
logger.debug('HTTP status=%s' % status)
|
|
if status == 304:
|
|
# No new data, based on the etag or modified values.
|
|
# We need to update the modified time in the
|
|
# storage, though, so we know that what we have
|
|
# stored is up to date.
|
|
self.storage[key] = (now, cached_content)
|
|
|
|
# Return the data from the cache, since
|
|
# the parsed data will be empty.
|
|
parsed_result = cached_content
|
|
elif status == 200:
|
|
# There is new content, so store it unless there was an error.
|
|
error = parsed_result.get('bozo_exception')
|
|
if not error:
|
|
logger.debug('Updating stored data for %s' % url)
|
|
self.storage[key] = (now, parsed_result)
|
|
else:
|
|
logger.warning('Not storing data with exception: %s',
|
|
error)
|
|
else:
|
|
logger.warning('Not updating cache with HTTP status %s', status)
|
|
|
|
return parsed_result
|