add token loader, .flask_sqlalchemy, jsonencode(), base2048

src/suou/signing.py

@@ -14,15 +14,17 @@ This software is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 """
 
+from abc import ABC
+from base64 import b64decode
+from typing import Any, Callable
 from itsdangerous import TimestampSigner
 
-from suou.iding import Siq
+from .codecs import want_str
+from .iding import Siq
 
 class UserSigner(TimestampSigner):
     """
-    Instance itsdangerous.TimestampSigner() from a user ID.
-
-    XXX UNTESTED!!!
+    itsdangerous.TimestampSigner() instanced from a user ID, with token generation and validation capabilities.
     """
     user_id: int
     def __init__(self, master_secret: bytes, user_id: int, user_secret: bytes, **kwargs):
@@ -30,4 +32,21 @@ class UserSigner(TimestampSigner):
         self.user_id = user_id
     def token(self) -> str:
         return self.sign(Siq(self.user_id).to_base64()).decode('ascii')
+    @classmethod
+    def split_token(cls, /, token: str | bytes) :
+        a, b, c = want_str(token).rsplit('.', 2)
+        return b64decode(a), b, b64decode(c)
 
+
+class HasSigner(ABC):
+    '''
+    Abstract base class for INTERNAL USE.
+    '''
+    signer: Callable[Any, UserSigner]
+
+    @classmethod
+    def __instancehook__(cls, obj) -> bool:
+        return callable(getattr(obj, 'signer', None))
+
+
+__all__ = ('UserSigner', )