[Cubicweb] Understanding _cw

Aurélien Campéas aurelien.campeas at logilab.fr
Wed May 14 18:08:36 CEST 2014


The mysterious _cw object has always bothered my, because
it can be different things in the same places in different

For instance, in CubicWeb 3.18, _cw can be either a Session
object or a CubicWebTwistedRequestAdapter object (AFAIK).

"_cw" is used in views, entities and hooks.

I tried to compute the precise interface of _cw in 3.19, and
here's the method list I got:

>>> cubicwebrequestbase.intersection(clientconnection)
set(['execute', 'describe', 'drop_entity_cache', 'entity_metas',
'call_service', 'set_entity_cache', 'cached_entities', 'source_defs',

(ClientConnection replaces Session in 3.19 for most purposes)

Also hooks have this too.

Is it reasonnable ?

In practice, I've learnt to organize my application code to deal with
this, but it hurts.

Then, there is ClientConnection (from repoapi.py) vs Connection (from

>>> connection.intersection(clientconnection)
set(['security_enabled', 'execute', 'rollback', 'drop_entity_cache',
'entity_metas', 'call_service', 'deny_all_hooks_but',
'cached_entities', 'allow_all_hooks_but', 'set_entity_cache',
'system_sql', 'commit', 'source_defs', 'entity_cache'])

So I feel like we could separate a bit more concerns and provide
*explicit* interfaces. Especially, the _cw object should be clearly

This is only food for thought and the start of an investigation ...


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