Commit cc0ac26f authored by Anssi Kääriäinen's avatar Anssi Kääriäinen
Browse files

Fixed #19273 -- Fixed DB cache backend on pg 9.0+ and py3 

There was a problem caused by Postgres 9.0+ having bytea_output default
value of 'hex' and cache backend inserting the content as 'bytes' into
a column of type TEXT. Fixed by converting the bytes value to a string
before insert.
parent 04a7ea32

django/core/cache/backends/db.py

+8 −4
Original line number Diff line number Diff line
@@ -11,7 +11,7 @@ except ImportError: 
from django.conf import settings

from django.core.cache.backends.base import BaseCache

from django.db import connections, router, transaction, DatabaseError

from django.utils import timezone

from django.utils import timezone, six

from django.utils.encoding import force_bytes
@@ -104,7 +104,11 @@ class DatabaseCache(BaseDatabaseCache): 
        if num > self._max_entries:

            self._cull(db, cursor, now)

        pickled = pickle.dumps(value, pickle.HIGHEST_PROTOCOL)

        encoded = base64.b64encode(pickled).strip()

        b64encoded = base64.b64encode(pickled)

        # The DB column is expecting a string, so make sure the value is a

        # string, not bytes. Refs #19274.

        if six.PY3:

            b64encoded = b64encoded.decode('latin1')

        cursor.execute("SELECT cache_key, expires FROM %s "

                       "WHERE cache_key = %%s" % table, [key])

        try:
@@ -113,11 +117,11 @@ class DatabaseCache(BaseDatabaseCache): 
                    (mode == 'add' and result[1] < now)):

                cursor.execute("UPDATE %s SET value = %%s, expires = %%s "

                               "WHERE cache_key = %%s" % table,

                               [encoded, connections[db].ops.value_to_db_datetime(exp), key])

                               [b64encoded, connections[db].ops.value_to_db_datetime(exp), key])

            else:

                cursor.execute("INSERT INTO %s (cache_key, value, expires) "

                               "VALUES (%%s, %%s, %%s)" % table,

                               [key, encoded, connections[db].ops.value_to_db_datetime(exp)])

                               [key, b64encoded, connections[db].ops.value_to_db_datetime(exp)])

        except DatabaseError:

            # To be threadsafe, updates/inserts are allowed to fail silently

            transaction.rollback_unless_managed(using=db)