diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/sqlalchemy/ext/baked.py | 12 | ||||
| -rw-r--r-- | lib/sqlalchemy/orm/events.py | 42 | ||||
| -rw-r--r-- | lib/sqlalchemy/orm/query.py | 5 |
3 files changed, 50 insertions, 9 deletions
diff --git a/lib/sqlalchemy/ext/baked.py b/lib/sqlalchemy/ext/baked.py index 44e28d045..d18a35a40 100644 --- a/lib/sqlalchemy/ext/baked.py +++ b/lib/sqlalchemy/ext/baked.py @@ -225,6 +225,7 @@ class BakedQuery(object): query = self._as_query(session) context = query._compile_context() + self._bake_subquery_loaders(session, context) context.session = None context.query = query = context.query.with_session(None) @@ -242,7 +243,13 @@ class BakedQuery(object): "_joinpoint", ): query.__dict__.pop(attr, None) - self._bakery[self._effective_key(session)] = context + + # if the query is not safe to cache, we still do everything as though + # we did cache it, since the receiver of _bake() assumes subqueryload + # context was set up, etc. + if context.query._bake_ok: + self._bakery[self._effective_key(session)] = context + return context def to_query(self, query_or_session): @@ -332,6 +339,9 @@ class BakedQuery(object): like a Query object. """ + if "baked_queries" not in context.attributes: + return + for k, cache_key, query in context.attributes["baked_queries"]: bk = BakedQuery( self._bakery, lambda sess, q=query: q.with_session(sess) diff --git a/lib/sqlalchemy/orm/events.py b/lib/sqlalchemy/orm/events.py index 5bb67b68f..2998a7639 100644 --- a/lib/sqlalchemy/orm/events.py +++ b/lib/sqlalchemy/orm/events.py @@ -2397,12 +2397,31 @@ class QueryEvents(event.Events): The event should normally be listened with the ``retval=True`` parameter set, so that the modified query may be returned. - .. warning:: If the :meth:`.QueryEvents.before_compile` event is to - be applied to :class:`.Query` objects that are used for lazy loading - of :func:`.relationships` (as described at :ref:`lazy_loading`), - it may be necessary to set :paramref:`.relationship.bake_queries` - to ``False``, else the :meth:`.QueryEvents.before_compile` event - will not be invoked for each lazy load operation. + The :meth:`.QueryEvents.before_compile` event by default + will disallow "baked" queries from caching a query, if the event + hook returns a new :class:`.Query` object. This affects both direct + use of the baked query extension as well as its operation within + lazy loaders and eager loaders for relationships. In order to + re-establish the query being cached, apply the event adding the + ``bake_ok`` flag:: + + @event.listens_for( + Query, "before_compile", retval=True, bake_ok=True) + def my_event(query): + for desc in query.column_descriptions: + if desc['type'] is User: + entity = desc['entity'] + query = query.filter(entity.deleted == False) + return query + + When ``bake_ok`` is set to True, the event hook will only be invoked + once, and not called for subsequent invocations of a particular query + that is being cached. + + .. versionadded:: 1.3.11 - added the "bake_ok" flag to the + :meth:`.QueryEvents.before_compile` event and disallowed caching via + the "baked" extension from occurring for event handlers that + return a new :class:`.Query` object if this flag is not set. .. seealso:: @@ -2410,6 +2429,7 @@ class QueryEvents(event.Events): :meth:`.QueryEvents.before_compile_delete` + :ref:`baked_with_before_compile` """ @@ -2494,7 +2514,7 @@ class QueryEvents(event.Events): """ @classmethod - def _listen(cls, event_key, retval=False, **kw): + def _listen(cls, event_key, retval=False, bake_ok=False, **kw): fn = event_key._listen_fn if not retval: @@ -2508,5 +2528,13 @@ class QueryEvents(event.Events): return fn(*arg, **kw) event_key = event_key.with_wrapper(wrap) + else: + # don't assume we can apply an attribute to the callable + def wrap(*arg, **kw): + return fn(*arg, **kw) + + event_key = event_key.with_wrapper(wrap) + + wrap._bake_ok = bake_ok event_key.base_listen(**kw) diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py index 92f9ee952..fc443d053 100644 --- a/lib/sqlalchemy/orm/query.py +++ b/lib/sqlalchemy/orm/query.py @@ -127,6 +127,7 @@ class Query(Generative): _orm_only_from_obj_alias = True _current_path = _path_registry _has_mapper_entities = False + _bake_ok = True lazy_loaded_from = None """An :class:`.InstanceState` that is using this :class:`.Query` for a @@ -3812,8 +3813,10 @@ class Query(Generative): if self.dispatch.before_compile: for fn in self.dispatch.before_compile: new_query = fn(self) - if new_query is not None: + if new_query is not None and new_query is not self: self = new_query + if not fn._bake_ok: + self._bake_ok = False context = QueryContext(self) |