"""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 = {}
[docs]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,
groups=set(user._groups) if hasattr(user, '_groups') else None,
properties=dict(user._properties)
if hasattr(user, '_properties') else None)
clone.cw_attr_cache = dict(user.cw_attr_cache)
return clone
[docs]def cnx_attach_entity(cnx, entity):
"""Attach an entity to a cnx."""
entity._cw = cnx
if entity.cw_rset:
entity.cw_rset.req = cnx
[docs]def cached_build_user(repo, eid):
"""Cached version of
:meth:`cubicweb.server.repository.Repository._build_user`
"""
with repo.internal_cnx() as cnx:
if eid in _user_cache:
entity = clone_user(repo, _user_cache[eid])
# XXX the cnx is needed here so that the CWUser instance has an
# access to the vreg, which it needs when its 'prefered_language'
# property is accessed.
# If this property did not need a cnx to access a vreg, we could
# avoid the internal_cnx() and save more time.
cnx_attach_entity(cnx, entity)
return entity
user = repo._build_user(cnx, eid)
user.cw_clear_relation_cache()
_user_cache[eid] = clone_user(repo, user)
return user
[docs]def clear_cache():
"""Clear the user cache"""
_user_cache.clear()
[docs]def includeme(config):
"""Start the cache maintenance loop task.
Automatically included by :func:`pyramid_cubicweb.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)