Redis+Trio support

quart_session/redis_trio/serialization.py

@@ -0,0 +1,60 @@
+# -*- coding: utf-8 -*-
+"""
+    quart_session.redis_trio.serialization
+    ~~~~~~~~~~~~~~~~~~~~~~
+
+    A simple Redis Trio client.
+
+    :copyright: (c) 2017 by Bogdan Paul Popa.
+    :copyright: (c) 2019 by Oleksii Aleksieiev.
+    :copyright: (c) 2020 by dsc.
+    :license: BSD, see LICENSE for more details.
+"""
+
+from collections import namedtuple
+
+#: Wrapper class for values that don't have to be quoted.
+atom = namedtuple("atom", ("value",))
+
+#: The set of characters that must be escaped before being sent as
+#: Redis strings.
+escapes = {
+    ord(b"\0"): rb"\x00",
+    ord(b"\n"): rb"\n",
+    ord(b"\r"): rb"\r",
+    ord(b"\\"): rb"\\",
+    ord(b'"'): rb'\"',
+}
+
+
+def serialize(x):
+    """Serialize `x` so that it can safely be sent to Redis.
+
+    Parameters:
+      x(object): The value to serialize.
+
+    Returns:
+      bytes: The serialized value.
+    """
+    if isinstance(x, atom):
+        return x.value
+    elif isinstance(x, bytes):
+        return quote(x)
+    elif isinstance(x, str):
+        return quote(x.encode("utf-8"))
+    elif isinstance(x, (float, int)):
+        return str(x).encode("ascii")
+    else:
+        return serialize(str(x))
+
+
+def quote(bs):
+    return b'"' + bytes(escape(bs)) + b'"'
+
+
+def escape(bs):
+    for c in bs:
+        if c in escapes:
+            yield from escapes[c]
+        else:
+            yield c