"""Various tools.
.. warning::
This module should be considered as internal implementation details. Use
with caution, as the API may change without notice.
"""
#: A short-term cache for user clones.
#: used by cached_build_user to speed-up repetitive calls to build_user
#: The expiration is handled in a dumb and brutal way: the whole cache is
#: cleared every 5 minutes.
_user_cache = {}
def clone_user(repo, user):
"""Clone a CWUser instance.
.. warning::
The returned clone is detached from any cnx.
Before using it in any way, it should be attached to a cnx that has not
this user already loaded.
"""
CWUser = repo.vreg['etypes'].etype_class('CWUser')
clone = CWUser(
None,
rset=user.cw_rset.copy(),
row=user.cw_row,
col=user.cw_col)
clone.cw_attr_cache = dict(user.cw_attr_cache)
return clone
def cnx_attach_entity(cnx, entity):
"""Attach an entity to a cnx."""
entity._cw = cnx
if entity.cw_rset:
entity.cw_rset.req = cnx
def cached_build_user(repo, eid):
"""Cached version of
:meth:`cubicweb.server.repository.Repository._build_user`
"""
if eid in _user_cache:
user, lang = _user_cache[eid]
entity = clone_user(repo, user)
return entity, lang
with repo.internal_cnx() as cnx:
user = repo._build_user(cnx, eid)
lang = user.prefered_language()
user.cw_clear_relation_cache()
_user_cache[eid] = (clone_user(repo, user), lang)
return user, lang
def clear_cache():
"""Clear the user cache"""
_user_cache.clear()
def includeme(config):
"""Start the cache maintenance loop task.
Automatically included by :func:`cubicweb.pyramid.make_cubicweb_application`.
"""
repo = config.registry['cubicweb.repository']
interval = int(config.registry.settings.get(
'cubicweb.usercache.expiration_time', 60 * 5))
repo.looping_task(interval, clear_cache)