# -*- coding: utf-8 -*-
-# Copyright (c) 2014 Jack Kaliko <kaliko@azylum.org>
+# Copyright (c) 2014-2015, 2020 kaliko <kaliko@azylum.org>
# Copyright (c) 2012, 2013 Eric Larson <eric@ionrock.org>
#
# This program is free software: you can redistribute it and/or modify
import email.utils
+from requests import Session, Request, Timeout, ConnectionError
+
+from sima import SOCKET_TIMEOUT, WAIT_BETWEEN_REQUESTS
+from sima.utils.utils import WSError, WSTimeout, WSHTTPError, Throttle
from .cache import DictCache
class CacheController(object):
"""An interface to see if request should cached or not.
"""
+ CACHE_ANYWAY = False
+
def __init__(self, cache=None, cache_etags=True):
self.cache = cache or DictCache()
self.cache_etags = cache_etags
if not path:
path = "/"
- # Order of params might changed
- query = ''.join(sorted(query.split('&')))
# Could do syntax based normalization of the URI before
# computing the digest. See Section 6.2.2 of Std 66.
request_uri = query and "?".join([path, query]) or path
retval = dict(parts_with_args + parts_wo_args)
return retval
- def cached_request(self, url, headers):
+ def cached_request(self, request):
"""Return the cached resquest if available and fresh
"""
- cache_url = self.cache_url(url)
- cc = self.parse_cache_control(headers)
+ cache_url = self.cache_url(request.url)
+ cc = self.parse_cache_control(request.headers)
# non-caching states
no_cache = True if 'no-cache' in cc else False
if 'max-age' in cc and cc['max-age'] == 0:
no_cache = True
-
# see if it is in the cache anyways
in_cache = self.cache.get(cache_url)
if no_cache or not in_cache:
for header in varied_headers:
# If our headers don't match for the headers listed in
# the vary header, then don't use the cached response
- if headers.get(header, None) != original_headers.get(header):
+ if request.headers.get(header, None) != original_headers.get(header):
return False
now = time.time()
self.cache.delete(cache_url)
if 'etag' in resp.headers:
- headers['If-None-Match'] = resp.headers['ETag']
+ request.headers['If-None-Match'] = resp.headers['ETag']
if 'last-modified' in resp.headers:
- headers['If-Modified-Since'] = resp.headers['Last-Modified']
+ request.headers['If-Modified-Since'] = resp.headers['Last-Modified']
# return the original handler
return False
- def add_headers(self, url):
- resp = self.cache.get(url)
- if resp and 'etag' in resp.headers:
- return {'If-None-Match': resp.headers['etag']}
- return {}
-
def cache_response(self, request, resp):
"""
Algorithm for caching requests.
elif 'expires' in resp.headers:
if resp.headers['expires']:
self.cache.set(cache_url, resp)
+ # Force one month max age if no Cache-Control header is found
+ # Overriding header disappearance on LastFM web service...
+ # https://getsatisfaction.com/lastfm/topics/-web-api-http-cache-control-header
+ elif CacheController.CACHE_ANYWAY:
+ resp.headers['Cache-Control'] = 'max-age=2419200'
+ self.cache.set(cache_url, resp)
def update_cached_response(self, request, response):
"""On a 304 we will get a new set of headers that we want to
resp.from_cache = True
return resp
+
+
+class HttpClient:
+ def __init__(self, cache=None, stats=None):
+ """
+ Prepare http request
+ Use cached elements or proceed http request
+ """
+ self.stats = stats
+ self.controller = CacheController(cache)
+ self.sess = Session()
+
+ def __call__(self, ress, payload):
+ req = Request('GET', ress, params=payload,).prepare()
+ if self.stats:
+ self.stats.update(total=self.stats.get('total')+1)
+ cached_response = self.controller.cached_request(req)
+ if cached_response:
+ if self.stats:
+ self.stats.update(ccontrol=self.stats.get('ccontrol')+1)
+ return cached_response
+ try:
+ return self.fetch_ws(req)
+ except Timeout:
+ raise WSTimeout('Failed to reach server within {0}s'.format(
+ SOCKET_TIMEOUT))
+ except ConnectionError as err:
+ raise WSError(err)
+
+ @Throttle(WAIT_BETWEEN_REQUESTS)
+ def fetch_ws(self, prepreq):
+ """fetch from web service"""
+ settings = self.sess.merge_environment_settings(prepreq.url, {}, None, False, None)
+ resp = self.sess.send(prepreq, timeout=SOCKET_TIMEOUT, **settings)
+ if resp.status_code == 304:
+ self.stats.update(etag=self.stats.get('etag')+1)
+ resp = self.controller.update_cached_response(prepreq, resp)
+ elif resp.status_code != 200:
+ raise WSHTTPError('{0.status_code}: {0.reason}'.format(resp))
+ self.controller.cache_response(resp.request, resp)
+ return resp
+
+# VIM MODLINE
+# vim: ai ts=4 sw=4 sts=4 expandtab