Update redis, and implement a custom channel layer to send datetime/decimal objects

gestioasso/settings/cof_prod.py

@@ -148,7 +148,7 @@ CACHES = {
 
 CHANNEL_LAYERS = {
     "default": {
-        "BACKEND": "channels_redis.core.RedisChannelLayer",
+        "BACKEND": "shared.channels.ChannelLayer",
         "CONFIG": {
             "hosts": [
                 (

requirements-prod.txt

@@ -5,7 +5,7 @@ psycopg2<2.8
 
 # Redis
 django-redis-cache==3.0.*
-redis~=2.10.6
+redis==3.5.*
 channels-redis==3.4.*
 
 # ASGI protocol and HTTP server

shared/channels.py

@@ -0,0 +1,45 @@
+import datetime
+import random
+from decimal import Decimal
+
+import msgpack
+from channels_redis.core import RedisChannelLayer
+
+
+def encode_kf(obj):
+    if isinstance(obj, Decimal):
+        return {"__decimal__": True, "as_str": str(obj)}
+    elif isinstance(obj, datetime.datetime):
+        return {"__datetime__": True, "as_str": obj.strftime("%Y%m%dT%H:%M:%S.%f")}
+    return obj
+
+
+def decode_kf(obj):
+    if "__decimal__" in obj:
+        obj = Decimal(obj["as_str"])
+    elif "__datetime__" in obj:
+        obj = datetime.datetime.strptime(obj["as_str"], "%Y%m%dT%H:%M:%S.%f")
+    return obj
+
+
+class ChannelLayer(RedisChannelLayer):
+    def serialize(self, message):
+        """Serializes to a byte string."""
+        value = msgpack.packb(message, default=encode_kf, use_bin_type=True)
+
+        if self.crypter:
+            value = self.crypter.encrypt(value)
+
+        # As we use an sorted set to expire messages
+        # we need to guarantee uniqueness, with 12 bytes.
+        random_prefix = random.getrandbits(8 * 12).to_bytes(12, "big")
+        return random_prefix + value
+
+    def deserialize(self, message):
+        """Deserializes from a byte string."""
+        # Removes the random prefix
+        message = message[12:]
+
+        if self.crypter:
+            message = self.crypter.decrypt(message, self.expiry + 10)
+        return msgpack.unpackb(message, object_hook=decode_kf, raw=False)