[Plugin] balance: Added reverting feature

flaschengeist/plugins/balance/__init__.py

@@ -3,17 +3,17 @@
 Extends users plugin with balance functions
 """
 
-from http.client import NO_CONTENT
 from datetime import datetime, timezone
-from flask import Blueprint, jsonify, request
+from flask import Blueprint, request
 from werkzeug.exceptions import Forbidden, BadRequest
 
 from flaschengeist import logger
+from flaschengeist.utils import HTTP
 from flaschengeist.models.session import Session
 from flaschengeist.utils.datetime import from_iso_format
 from flaschengeist.decorator import login_required
 from flaschengeist.controller import userController
-from flaschengeist.plugins import Plugin, update_user_hook
+from flaschengeist.plugins import Plugin, before_update_user
 
 from . import balance_controller, permissions, models
 
@@ -26,7 +26,7 @@ class BalancePlugin(Plugin):
     def __init__(self, config):
         super().__init__(blueprint=balance_bp, permissions=permissions.permissions)
 
-        @update_user_hook
+        @before_update_user
         def set_default_limit(user):
             if "limit" in config:
                 limit = config["limit"]
@@ -59,7 +59,7 @@ def get_limit(userid, current_session: Session):
     ):
         raise Forbidden
 
-    return jsonify({"limit": balance_controller.get_limit(user)})
+    return {"limit": balance_controller.get_limit(user)}
 
 
 @balance_bp.route("/users/<userid>/balance/limit", methods=["PUT"])
@@ -88,7 +88,7 @@ def set_limit(userid, current_session: Session):
     except (TypeError, KeyError):
         raise BadRequest
     balance_controller.set_limit(user, limit)
-    return "", NO_CONTENT
+    return HTTP.no_content()
 
 
 @balance_bp.route("/users/<userid>/balance", methods=["GET"])
@@ -125,8 +125,8 @@ def get_balance(userid, current_session: Session):
     else:
         end = datetime.now(tz=timezone.utc)
 
-    balance = balance_controller.get(user, start, end)
-    return jsonify({"credit": balance[0], "debit": balance[1], "balance": balance[2]})
+    balance = balance_controller.get_balance(user, start, end)
+    return {"credit": balance[0], "debit": balance[1], "balance": balance[2]}
 
 
 @balance_bp.route("/users/<userid>/balance", methods=["PUT"])
@@ -144,7 +144,7 @@ def change_balance(userid, current_session: Session):
         current_session: Session sent with Authorization Header
 
     Returns:
-        JSON object containing credit, debit and balance or HTTP error
+        JSON encoded transaction (201) or HTTP error
     """
 
     data = request.get_json()
@@ -164,8 +164,7 @@ def change_balance(userid, current_session: Session):
         if (sender == current_session._user and sender.has_permission(permissions.SEND)) or (
             sender != current_session._user and current_session._user.has_permission(permissions.SEND_OTHER)
         ):
-            balance_controller.send(sender, user, data["amount"], current_session._user)
-            return "", NO_CONTENT
+            return HTTP.created(balance_controller.send(sender, user, data["amount"], current_session._user))
 
     elif (
         amount < 0
@@ -174,7 +173,31 @@ def change_balance(userid, current_session: Session):
             or current_session._user.has_permission(permissions.DEBIT)
         )
     ) or (amount > 0 and current_session._user.has_permission(permissions.CREDIT)):
-        balance_controller.change_balance(user, data["amount"], current_session._user)
-        return "", NO_CONTENT
+        return HTTP.created(balance_controller.change_balance(user, data["amount"], current_session._user))
 
     raise Forbidden
+
+
+@balance_bp.route("/balance/<int:transaction_id>", methods=["DELETE"])
+@login_required()
+def reverse_transaction(transaction_id, current_session: Session):
+    """Reverse a transaction
+
+    Route: ``/balance/<int:transaction_id>`` | Method: ``DELETE``
+
+    Args:
+        transaction_id: Identifier of the transaction
+        current_session: Session sent with Authorization Header
+
+    Returns:
+        JSON encoded reversal (transaction) (201) or HTTP error
+    """
+
+    transaction = balance_controller.get_transaction(transaction_id)
+    if current_session._user.has_permission(permissions.REVERSAL) or (
+        transaction.sender_ == current_session._user
+        and (datetime.now(tz=timezone.utc) - transaction.time).total_seconds() < 10
+    ):
+        reversal = balance_controller.reverse_transaction(transaction, current_session._user)
+        return HTTP.created(reversal)
+    raise Forbidden

flaschengeist/plugins/balance/balance_controller.py

@@ -5,13 +5,14 @@
 
 from sqlalchemy import func
 from datetime import datetime, timezone
-from werkzeug.exceptions import BadRequest
+from werkzeug.exceptions import BadRequest, NotFound
 
 from flaschengeist.database import db
 from flaschengeist.models.user import User
 
 from .models import Transaction
 from . import permissions
+from ... import logger
 
 __attribute_limit = "balance_limit"
 
@@ -26,7 +27,7 @@ def get_limit(user: User) -> float:
     return user.get_attribute(__attribute_limit, default=None)
 
 
-def get(user, start: datetime = None, end: datetime = None):
+def get_balance(user, start: datetime = None, end: datetime = None):
     if not start:
         start = datetime.fromtimestamp(0, tz=timezone.utc)
     if not end:
@@ -35,6 +36,7 @@ def get(user, start: datetime = None, end: datetime = None):
     credit = (
         db.session.query(func.sum(Transaction.amount))
         .filter(Transaction.receiver_ == user)
+        .filter(Transaction._reversal_id.is_(None))  # ignore reverted transactions
         .filter(start <= Transaction.time)
         .filter(Transaction.time <= end)
         .scalar()
@@ -43,6 +45,7 @@ def get(user, start: datetime = None, end: datetime = None):
     debit = (
         db.session.query(func.sum(Transaction.amount))
         .filter(Transaction.sender_ == user)
+        .filter(Transaction._reversal_id.is_(None))  # ignore reverted transactions
         .filter(start <= Transaction.time)
         .filter(Transaction.time <= end)
         .scalar()
@@ -59,13 +62,15 @@ def send(sender: User, receiver, amount: float, author: User):
         receiver: User who receives the amount
         amount: Amount to send
         author: User authoring this transaction
+    Returns:
+        Transaction that was created
     Raises:
         BadRequest if amount <= 0
     """
     if amount <= 0:
         raise BadRequest
 
-    if sender.has_attribute(__attribute_limit):
+    if sender and sender.has_attribute(__attribute_limit):
         if (get(sender)[2] - amount) < sender.get_attribute(__attribute_limit) and not author.has_permission(
             permissions.EXCEED_LIMIT
         ):
@@ -74,6 +79,7 @@ def send(sender: User, receiver, amount: float, author: User):
     transaction = Transaction(sender_=sender, receiver_=receiver, amount=amount, author_=author)
     db.session.add(transaction)
     db.session.commit()
+    return transaction
 
 
 def change_balance(user, amount: float, author):
@@ -86,4 +92,25 @@ def change_balance(user, amount: float, author):
     """
     sender = user if amount < 0 else None
     receiver = user if amount > 0 else None
-    send(sender, receiver, abs(amount), author)
+    return send(sender, receiver, abs(amount), author)
+
+
+def get_transaction(transaction_id) -> Transaction:
+    transaction = Transaction.query.get(transaction_id)
+    if not transaction:
+        raise NotFound
+    return transaction
+
+
+def reverse_transaction(transaction: Transaction, author: User):
+    """Reverse a transaction
+
+    Args:
+        transaction: Transaction to reverse
+        author: User that wants the transaction to be reverted
+    """
+    reversal = send(transaction.receiver_, transaction.sender_, transaction.amount, author)
+    reversal.reversal = transaction
+    transaction.reversal = reversal
+    db.session.commit()
+    return reversal

flaschengeist/plugins/balance/models.py

@@ -1,4 +1,5 @@
-from datetime import datetime, timezone
+from datetime import datetime
+from typing import Optional
 
 from flaschengeist.models.user import User
 
@@ -8,19 +9,22 @@ from flaschengeist.models import ModelSerializeMixin, UtcDateTime
 
 class Transaction(db.Model, ModelSerializeMixin):
     __tablename__ = "balance_transaction"
-    id: int = db.Column("id", db.Integer, primary_key=True)
-    time: datetime = db.Column(UtcDateTime, nullable=False, default=datetime.now(tz=timezone.utc))
-    amount: float = db.Column(db.Numeric(precision=5, scale=2, asdecimal=False), nullable=False)
-
-    # Dummy properties used for JSON serialization (userid instead of full user)
-    sender_id: str = ""
-    receiver_id: str = ""
-    author_id: str = ""
-
     # Protected foreign key properties
     _receiver_id = db.Column("receiver_id", db.Integer, db.ForeignKey("user.id"))
     _sender_id = db.Column("sender_id", db.Integer, db.ForeignKey("user.id"))
     _author_id = db.Column("author_id", db.Integer, db.ForeignKey("user.id"), nullable=False)
+    _reversal_id = db.Column("reversal_id", db.Integer, db.ForeignKey("balance_transaction.id"))
+
+    # Public and exported member
+    id: int = db.Column("id", db.Integer, primary_key=True)
+    time: datetime = db.Column(UtcDateTime, nullable=False, default=UtcDateTime.current_utc)
+    amount: float = db.Column(db.Numeric(precision=5, scale=2, asdecimal=False), nullable=False)
+    reversal: Optional["Transaction"] = db.relationship("Transaction", foreign_keys=[_reversal_id])
+
+    # Dummy properties used for JSON serialization (userid instead of full user)
+    sender_id: Optional[str] = ""
+    receiver_id: Optional[str] = ""
+    author_id: Optional[str] = ""
 
     # Not exported relationships just in backend only
     sender_: User = db.relationship("User", foreign_keys=[_sender_id])
@@ -29,12 +33,21 @@ class Transaction(db.Model, ModelSerializeMixin):
 
     @property
     def sender_id(self):
-        return self.sender_.userid
+        return self.sender_.userid if self.sender_ else None
 
     @property
     def receiver_id(self):
-        return self.receiver_.userid
+        return self.receiver_.userid if self.receiver_ else None
 
     @property
     def author_id(self):
         return self.author_.userid
+
+    # Override to prevent circular dependencies (endless JSON)
+    def serialize(self):
+        d = super().serialize()
+        if d["reversal"]:
+            d["reversal"].reversal = None
+        else:
+            d["reversal"] = None
+        return d

flaschengeist/plugins/balance/permissions.py

@@ -21,4 +21,7 @@ SET_LIMIT = "balance_set_limit"
 EXCEED_LIMIT = "balance_exceed_limit"
 """Allow sending / sub while exceeding the set limit"""
 
+REVERSAL = "balance_reversal"
+"""Allow reverting transactions"""
+
 permissions = [value for key, value in globals().items() if not key.startswith("_")]

flaschengeist/plugins/message_mail.py

@@ -7,7 +7,7 @@ from flaschengeist.models.user import User
 from flaschengeist.controller import userController
 from flaschengeist.controller.messageController import Message
 
-from . import Plugin, send_message_hook
+from . import Plugin
 
 
 class MailMessagePlugin(Plugin):
@@ -20,7 +20,7 @@ class MailMessagePlugin(Plugin):
         self.crypt = config["CRYPT"]
         self.mail = config["MAIL"]
 
-        @send_message_hook
+        # @send_message_hook
         def dummy_send(msg):
             self.send_mail(msg)