--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/cubicweb/web/httpcache.py Sat Jan 16 13:48:51 2016 +0100
@@ -0,0 +1,181 @@
+# copyright 2003-2012 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This file is part of CubicWeb.
+#
+# CubicWeb is free software: you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with CubicWeb. If not, see <http://www.gnu.org/licenses/>.
+"""HTTP cache managers"""
+
+__docformat__ = "restructuredtext en"
+
+from time import mktime
+from datetime import datetime
+
+class NoHTTPCacheManager(object):
+ """default cache manager: set no-cache cache control policy"""
+ def __init__(self, view):
+ self.view = view
+ self.req = view._cw
+ self.cw_rset = view.cw_rset
+
+ def set_headers(self):
+ self.req.set_header('Cache-control', 'no-cache')
+ self.req.set_header('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')
+
+
+class MaxAgeHTTPCacheManager(NoHTTPCacheManager):
+ """max-age cache manager: set max-age cache control policy, with max-age
+ specified with the `cache_max_age` attribute of the view
+ """
+ def set_headers(self):
+ self.req.set_header('Cache-control',
+ 'max-age=%s' % self.view.cache_max_age)
+
+
+class EtagHTTPCacheManager(NoHTTPCacheManager):
+ """etag based cache manager for startup views
+
+ * etag is generated using the view name and the user's groups
+ * set policy to 'must-revalidate' and expires to the current time to force
+ revalidation on each request
+ """
+
+ def etag(self):
+ if not self.req.cnx: # session without established connection to the repo
+ return self.view.__regid__
+ return self.view.__regid__ + '/' + ','.join(sorted(self.req.user.groups))
+
+ def max_age(self):
+ # 0 to actually force revalidation
+ return 0
+
+ def last_modified(self):
+ """return view's last modified GMT time"""
+ return self.view.last_modified()
+
+ def set_headers(self):
+ req = self.req
+ try:
+ req.set_header('Etag', '"%s"' % self.etag())
+ except NoEtag:
+ super(EtagHTTPCacheManager, self).set_headers()
+ return
+ req.set_header('Cache-control',
+ 'must-revalidate,max-age=%s' % self.max_age())
+ mdate = self.last_modified()
+ # use a timestamp, not a formatted raw header, and let
+ # the front-end correctly generate it
+ # ("%a, %d %b %Y %H:%M:%S GMT" return localized date that
+ # twisted don't parse correctly)
+ req.set_header('Last-modified', mktime(mdate.timetuple()), raw=False)
+
+
+class EntityHTTPCacheManager(EtagHTTPCacheManager):
+ """etag based cache manager for view displaying a single entity
+
+ * etag is generated using entity's eid, the view name and the user's groups
+ * get last modified time from the entity definition (this may not be the
+ entity's modification time since a view may include some related entities
+ with a modification time to consider) using the `last_modified` method
+ """
+ def etag(self):
+ if self.cw_rset is None or len(self.cw_rset) == 0: # entity startup view for instance
+ return super(EntityHTTPCacheManager, self).etag()
+ if len(self.cw_rset) > 1:
+ raise NoEtag()
+ etag = super(EntityHTTPCacheManager, self).etag()
+ eid = self.cw_rset[0][0]
+ if self.req.user.owns(eid):
+ etag += ',owners'
+ return str(eid) + '/' + etag
+
+
+class NoEtag(Exception):
+ """an etag can't be generated"""
+
+__all__ = ('GMTOFFSET',
+ 'NoHTTPCacheManager', 'MaxAgeHTTPCacheManager',
+ 'EtagHTTPCacheManager', 'EntityHTTPCacheManager')
+
+# monkey patching, so view doesn't depends on this module and we have all
+# http cache related logic here
+
+from cubicweb import view as viewmod
+
+def set_http_cache_headers(self):
+ self.http_cache_manager(self).set_headers()
+viewmod.View.set_http_cache_headers = set_http_cache_headers
+
+
+def last_modified(self):
+ """return the date/time where this view should be considered as
+ modified. Take care of possible related objects modifications.
+
+ /!\ must return GMT time /!\
+ """
+ # XXX check view module's file modification time in dev mod ?
+ ctime = datetime.utcnow()
+ if self.cache_max_age:
+ mtime = self._cw.header_if_modified_since()
+ if mtime:
+ tdelta = (ctime - mtime)
+ if tdelta.days * 24*60*60 + tdelta.seconds <= self.cache_max_age:
+ return mtime
+ # mtime = ctime will force page rerendering
+ return ctime
+viewmod.View.last_modified = last_modified
+
+
+# configure default caching
+viewmod.View.http_cache_manager = NoHTTPCacheManager
+# max-age=0 to actually force revalidation when needed
+viewmod.View.cache_max_age = 0
+
+viewmod.StartupView.http_cache_manager = MaxAgeHTTPCacheManager
+viewmod.StartupView.cache_max_age = 60*60*2 # stay in http cache for 2 hours by default
+
+
+### HTTP Cache validator ############################################
+
+
+
+def get_validators(headers_in):
+ """return a list of http condition validator relevant to this request
+ """
+ result = []
+ for header, func in VALIDATORS:
+ value = headers_in.getHeader(header)
+ if value is not None:
+ result.append((func, value))
+ return result
+
+
+def if_modified_since(ref_date, headers_out):
+ last_modified = headers_out.getHeader('last-modified')
+ if last_modified is None:
+ return True
+ return ref_date < last_modified
+
+def if_none_match(tags, headers_out):
+ etag = headers_out.getHeader('etag')
+ if etag is None:
+ return True
+ return not ((etag in tags) or ('*' in tags))
+
+VALIDATORS = [
+ ('if-modified-since', if_modified_since),
+ #('if-unmodified-since', if_unmodified_since),
+ ('if-none-match', if_none_match),
+ #('if-modified-since', if_modified_since),
+]