diff options
Diffstat (limited to 'lib/sqlalchemy/ext/baked.py')
| -rw-r--r-- | lib/sqlalchemy/ext/baked.py | 47 |
1 files changed, 42 insertions, 5 deletions
diff --git a/lib/sqlalchemy/ext/baked.py b/lib/sqlalchemy/ext/baked.py index c0fe963ac..8cae6e24b 100644 --- a/lib/sqlalchemy/ext/baked.py +++ b/lib/sqlalchemy/ext/baked.py @@ -261,12 +261,13 @@ class Result(object): against a target :class:`.Session`, and is then invoked for results. """ - __slots__ = 'bq', 'session', '_params' + __slots__ = 'bq', 'session', '_params', '_post_criteria' def __init__(self, bq, session): self.bq = bq self.session = session self._params = {} + self._post_criteria = [] def params(self, *args, **kw): """Specify parameters to be replaced into the string SQL statement.""" @@ -280,8 +281,37 @@ class Result(object): self._params.update(kw) return self + def _using_post_criteria(self, fns): + if fns: + self._post_criteria.extend(fns) + return self + + def with_post_criteria(self, fn): + """Add a criteria function that will be applied post-cache. + + This adds a function that will be run against the + :class:`.Query` object after it is retrieved from the + cache. Functions here can be used to alter the query in ways + that **do not affect the SQL output**, such as execution options + and shard identifiers (when using a shard-enabled query object) + + .. warning:: :meth:`.Result.with_post_criteria` functions are applied + to the :class:`.Query` object **after** the query's SQL statement + object has been retrieved from the cache. Any operations here + which intend to modify the SQL should ensure that + :meth:`.BakedQuery.spoil` was called first. + + .. versionadded:: 1.2 + + + """ + return self._using_post_criteria([fn]) + def _as_query(self): - return self.bq._as_query(self.session).params(self._params) + q = self.bq._as_query(self.session).params(self._params) + for fn in self._post_criteria: + q = fn(q) + return q def __str__(self): return str(self._as_query()) @@ -304,8 +334,11 @@ class Result(object): context.statement.use_labels = True if context.autoflush and not context.populate_existing: self.session._autoflush() - return context.query.params(self._params).\ - with_session(self.session)._execute_and_instances(context) + q = context.query.params(self._params).with_session(self.session) + for fn in self._post_criteria: + q = fn(q) + + return q._execute_and_instances(context) def count(self): """return the 'count'. @@ -348,7 +381,9 @@ class Result(object): """ bq = self.bq.with_criteria(lambda q: q.slice(0, 1)) - ret = list(bq.for_session(self.session).params(self._params)) + ret = list( + bq.for_session(self.session).params(self._params). + _using_post_criteria(self._post_criteria)) if len(ret) > 0: return ret[0] else: @@ -435,6 +470,8 @@ class Result(object): _lcl_get_clause = q._adapt_clause(_lcl_get_clause, True, False) q._criterion = _lcl_get_clause + for fn in self._post_criteria: + q = fn(q) return q # cache the query against a key that includes |