Add user soft delete ability via BitField flags, explicit on_delete CASCADE, Session.is_expired(), Session.use()

backend/linkpulse/models.py

@@ -3,13 +3,14 @@ This module defines the database models for the LinkPulse backend.
 It also provides a base model with database connection details.
 """
 
+import datetime
 from os import getenv
+from typing import Optional
 
 import structlog
-from peewee import AutoField, CharField, DateTimeField, ForeignKeyField, Model
-from playhouse.db_url import connect
-
 from linkpulse.utilities import utc_now
+from peewee import AutoField, CharField, DateTimeField, ForeignKeyField, BitField, Model
+from playhouse.db_url import connect
 
 logger = structlog.get_logger()
 
@@ -32,21 +33,52 @@ class User(BaseModel):
     id = AutoField(primary_key=True)
     # arbitrary max length, but statistically reasonable and limits UI concerns/abuse cases
     email = CharField(unique=True, max_length=45)
+    flags = BitField()
     # full hash with encoded salt/parameters, argon2 but assume nothing
     password_hash = CharField(max_length=96)
     created_at = DateTimeField(default=utc_now)
     updated_at = DateTimeField(default=utc_now)
+    # prefer soft deletes before hard deletes
+    deleted_at = DateTimeField(null=True)
+    deleted = flags.flag(1)
 
 
 class Session(BaseModel):
     """
     A session represents a user's login session.
+
+    For now, a session returned from the API implies it's validity.
+    In the future, sessions may be invalidated or revoked, but kept in the database AND returned.
+    This could allow sessions to be tracked and audited even after they are no longer valid, or allow more proper 'logout' messages.
     """
 
     token = CharField(unique=True, primary_key=True, max_length=32)
-    user = ForeignKeyField(User, backref="sessions")
+    user = ForeignKeyField(User, backref="sessions", on_delete="CASCADE")
 
     expiry = DateTimeField()
 
     created_at = DateTimeField(default=utc_now)
     last_used = DateTimeField(null=True)
+
+    def is_expired(
+        self, revoke: bool = True, now: Optional[datetime.datetime] = None
+    ) -> bool:
+        """
+        Check if the session is expired. If `revoke` is True, the session will be automatically revoked if it is expired.
+        """
+        if now is None:
+            now = utc_now()
+
+        if self.expiry < now:
+            if revoke:
+                self.delete_instance()
+            return True
+        return False
+
+    def use(self, now: Optional[datetime.datetime] = None):
+        """
+        Update the last_used field of the session.
+        """
+        if now is None:
+            now = utc_now()
+        self.last_used = now  # type: ignore