def get_updated_accounts(*, sender_account_balance, validated_block):
"""Return the updated balances of all accounts involved"""
existing_accounts = []
new_accounts = []
message = validated_block['message']
txs = message['txs']
total_amount = sum([tx['amount'] for tx in txs])
existing_accounts.append({
'account_number': validated_block['account_number'],
'balance': sender_account_balance - total_amount,
'balance_lock': get_message_hash(message=message)
})
for tx in txs:
amount = tx['amount']
recipient = tx['recipient']
recipient_account_balance = get_account_balance(account_number=recipient)
if recipient_account_balance is None:
new_accounts.append({
'account_number': recipient,
'balance': amount
})
else:
existing_accounts.append({
'account_number': recipient,
'balance': recipient_account_balance + amount
})
return existing_accounts, new_accounts
def account_balance_view(_, account_number):
"""
Return the balance for the given account
"""
return Response(
{'balance': get_account_balance(account_number=account_number)})
def is_block_valid(*, block):
"""
For given block verify:
- signature
- account balance exists
- amount sent does not exceed account balance
- balance key matches balance lock
Return boolean indicating validity, senders account balance
"""
account_number = block.get('account_number')
message = block.get('message')
signature = block.get('signature')
try:
verify_signature(message=sort_and_encode(message),
signature=signature,
verify_key=account_number)
except BadSignatureError:
return False, None
except Exception as e:
capture_exception(e)
logger.exception(e)
return False, None
account_balance = get_account_balance(account_number=account_number)
account_balance_lock = get_account_balance_lock(
account_number=account_number)
if account_balance is None:
logger.error(f'Account balance for {account_number} not found')
return False, None
total_amount_valid, error = is_total_amount_valid(
block=block, account_balance=account_balance)
if not total_amount_valid:
logger.error(error)
return False, None
balance_key = message.get('balance_key')
if balance_key != account_balance_lock:
logger.error(
f'Balance key of {balance_key} does not match balance lock of {account_balance_lock}'
)
return False, None
return True, account_balance
def balance(self, request, account_number=None):
return Response(
{'balance': get_account_balance(account_number=account_number)})