diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 08dffd774f..be61147b9b 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -17,9 +17,10 @@ import sys
import threading
import time
-from six import iteritems, iterkeys, itervalues
+from six import PY2, iteritems, iterkeys, itervalues
from six.moves import intern, range
+from canonicaljson import json
from prometheus_client import Histogram
from twisted.internet import defer
@@ -1216,3 +1217,32 @@ class _RollbackButIsFineException(Exception):
something went wrong.
"""
pass
+
+
+def db_to_json(db_content):
+ """
+ Take some data from a database row and return a JSON-decoded object.
+
+ Args:
+ db_content (memoryview|buffer|bytes|bytearray|unicode)
+ """
+ # psycopg2 on Python 3 returns memoryview objects, which we need to
+ # cast to bytes to decode
+ if isinstance(db_content, memoryview):
+ db_content = db_content.tobytes()
+
+ # psycopg2 on Python 2 returns buffer objects, which we need to cast to
+ # bytes to decode
+ if PY2 and isinstance(db_content, buffer):
+ db_content = bytes(db_content)
+
+ # Decode it to a Unicode string before feeding it to json.loads, so we
+ # consistenty get a Unicode-containing object out.
+ if isinstance(db_content, (bytes, bytearray)):
+ db_content = db_content.decode('utf8')
+
+ try:
+ return json.loads(db_content)
+ except Exception:
+ logging.warning("Tried to decode '%r' as JSON and failed", db_content)
+ raise
|
