diff options
Diffstat (limited to 'django/core/cache/backends/db.py')
| -rw-r--r-- | django/core/cache/backends/db.py | 105 |
1 files changed, 74 insertions, 31 deletions
diff --git a/django/core/cache/backends/db.py b/django/core/cache/backends/db.py index 3398e6a85b..c4429c80b3 100644 --- a/django/core/cache/backends/db.py +++ b/django/core/cache/backends/db.py @@ -1,7 +1,7 @@ "Database cache backend." from django.core.cache.backends.base import BaseCache -from django.db import connection, transaction, DatabaseError +from django.db import connections, router, transaction, DatabaseError import base64, time from datetime import datetime try: @@ -9,10 +9,31 @@ try: except ImportError: import pickle +class Options(object): + """A class that will quack like a Django model _meta class. + + This allows cache operations to be controlled by the router + """ + def __init__(self, table): + self.db_table = table + self.app_label = 'django_cache' + self.module_name = 'cacheentry' + self.verbose_name = 'cache entry' + self.verbose_name_plural = 'cache entries' + self.object_name = 'CacheEntry' + self.abstract = False + self.managed = True + self.proxy = False + class CacheClass(BaseCache): def __init__(self, table, params): BaseCache.__init__(self, params) - self._table = connection.ops.quote_name(table) + self._table = table + + class CacheEntry(object): + _meta = Options(table) + self.cache_model_class = CacheEntry + max_entries = params.get('max_entries', 300) try: self._max_entries = int(max_entries) @@ -25,78 +46,100 @@ class CacheClass(BaseCache): self._cull_frequency = 3 def get(self, key, default=None): - cursor = connection.cursor() - cursor.execute("SELECT cache_key, value, expires FROM %s WHERE cache_key = %%s" % self._table, [key]) + self.validate_key(key) + db = router.db_for_read(self.cache_model_class) + table = connections[db].ops.quote_name(self._table) + cursor = connections[db].cursor() + + cursor.execute("SELECT cache_key, value, expires FROM %s WHERE cache_key = %%s" % table, [key]) row = cursor.fetchone() if row is None: return default now = datetime.now() if row[2] < now: - cursor.execute("DELETE FROM %s WHERE cache_key = %%s" % self._table, [key]) - transaction.commit_unless_managed() + db = router.db_for_write(self.cache_model_class) + cursor = connections[db].cursor() + cursor.execute("DELETE FROM %s WHERE cache_key = %%s" % table, [key]) + transaction.commit_unless_managed(using=db) return default - value = connection.ops.process_clob(row[1]) + value = connections[db].ops.process_clob(row[1]) return pickle.loads(base64.decodestring(value)) def set(self, key, value, timeout=None): + self.validate_key(key) self._base_set('set', key, value, timeout) def add(self, key, value, timeout=None): + self.validate_key(key) return self._base_set('add', key, value, timeout) def _base_set(self, mode, key, value, timeout=None): if timeout is None: timeout = self.default_timeout - cursor = connection.cursor() - cursor.execute("SELECT COUNT(*) FROM %s" % self._table) + db = router.db_for_write(self.cache_model_class) + table = connections[db].ops.quote_name(self._table) + cursor = connections[db].cursor() + + cursor.execute("SELECT COUNT(*) FROM %s" % table) num = cursor.fetchone()[0] now = datetime.now().replace(microsecond=0) exp = datetime.fromtimestamp(time.time() + timeout).replace(microsecond=0) if num > self._max_entries: - self._cull(cursor, now) + self._cull(db, cursor, now) encoded = base64.encodestring(pickle.dumps(value, 2)).strip() - cursor.execute("SELECT cache_key, expires FROM %s WHERE cache_key = %%s" % self._table, [key]) + cursor.execute("SELECT cache_key, expires FROM %s WHERE cache_key = %%s" % table, [key]) try: result = cursor.fetchone() if result and (mode == 'set' or (mode == 'add' and result[1] < now)): - cursor.execute("UPDATE %s SET value = %%s, expires = %%s WHERE cache_key = %%s" % self._table, - [encoded, connection.ops.value_to_db_datetime(exp), key]) + cursor.execute("UPDATE %s SET value = %%s, expires = %%s WHERE cache_key = %%s" % table, + [encoded, connections[db].ops.value_to_db_datetime(exp), key]) else: - cursor.execute("INSERT INTO %s (cache_key, value, expires) VALUES (%%s, %%s, %%s)" % self._table, - [key, encoded, connection.ops.value_to_db_datetime(exp)]) + cursor.execute("INSERT INTO %s (cache_key, value, expires) VALUES (%%s, %%s, %%s)" % table, + [key, encoded, connections[db].ops.value_to_db_datetime(exp)]) except DatabaseError: # To be threadsafe, updates/inserts are allowed to fail silently - transaction.rollback_unless_managed() + transaction.rollback_unless_managed(using=db) return False else: - transaction.commit_unless_managed() + transaction.commit_unless_managed(using=db) return True def delete(self, key): - cursor = connection.cursor() - cursor.execute("DELETE FROM %s WHERE cache_key = %%s" % self._table, [key]) - transaction.commit_unless_managed() + self.validate_key(key) + db = router.db_for_write(self.cache_model_class) + table = connections[db].ops.quote_name(self._table) + cursor = connections[db].cursor() + + cursor.execute("DELETE FROM %s WHERE cache_key = %%s" % table, [key]) + transaction.commit_unless_managed(using=db) def has_key(self, key): + self.validate_key(key) + db = router.db_for_read(self.cache_model_class) + table = connections[db].ops.quote_name(self._table) + cursor = connections[db].cursor() + now = datetime.now().replace(microsecond=0) - cursor = connection.cursor() - cursor.execute("SELECT cache_key FROM %s WHERE cache_key = %%s and expires > %%s" % self._table, - [key, connection.ops.value_to_db_datetime(now)]) + cursor.execute("SELECT cache_key FROM %s WHERE cache_key = %%s and expires > %%s" % table, + [key, connections[db].ops.value_to_db_datetime(now)]) return cursor.fetchone() is not None - def _cull(self, cursor, now): + def _cull(self, db, cursor, now): if self._cull_frequency == 0: self.clear() else: - cursor.execute("DELETE FROM %s WHERE expires < %%s" % self._table, - [connection.ops.value_to_db_datetime(now)]) - cursor.execute("SELECT COUNT(*) FROM %s" % self._table) + table = connections[db].ops.quote_name(self._table) + cursor.execute("DELETE FROM %s WHERE expires < %%s" % table, + [connections[db].ops.value_to_db_datetime(now)]) + cursor.execute("SELECT COUNT(*) FROM %s" % table) num = cursor.fetchone()[0] if num > self._max_entries: - cursor.execute("SELECT cache_key FROM %s ORDER BY cache_key LIMIT 1 OFFSET %%s" % self._table, [num / self._cull_frequency]) - cursor.execute("DELETE FROM %s WHERE cache_key < %%s" % self._table, [cursor.fetchone()[0]]) + cursor.execute("SELECT cache_key FROM %s ORDER BY cache_key LIMIT 1 OFFSET %%s" % table, [num / self._cull_frequency]) + cursor.execute("DELETE FROM %s WHERE cache_key < %%s" % table, [cursor.fetchone()[0]]) def clear(self): - cursor = connection.cursor() - cursor.execute('DELETE FROM %s' % self._table) + db = router.db_for_write(self.cache_model_class) + table = connections[db].ops.quote_name(self._table) + cursor = connections[db].cursor() + cursor.execute('DELETE FROM %s' % table) |