def register_payment(self, sender: str, open_block_number: int,
balance: int, signature: str):
"""Register a payment.
Method will try to reconstruct (verify) balance update data
with a signature sent by the client.
If verification is succesfull, an internal payment state is updated.
Parameters:
sender (str): sender of the balance proof
open_block_number (int): block the channel was opened in
balance (int): updated balance
signature(str): balance proof to verify
"""
assert is_checksum_address(sender)
c = self.verify_balance_proof(sender, open_block_number, balance,
signature)
if balance <= c.balance:
raise InvalidBalanceAmount('The balance must not decrease.')
if balance > c.deposit:
raise InvalidBalanceProof(
'Balance must not be greater than deposit')
received = balance - c.balance
c.balance = balance
c.last_signature = signature
c.mtime = time.time()
self.state.set_channel(c)
self.log.debug(
'registered payment (sender %s, block number %s, new balance %s)',
c.sender, open_block_number, balance)
return c.sender, received
def verify_balance_proof(self, sender, open_block_number, balance,
signature):
"""Verify that a balance proof is valid and return the sender.
This method just verifies if the balance proof is valid - no state update is performed.
:returns: Channel, if it exists
"""
assert is_checksum_address(sender)
if (sender, open_block_number) in self.unconfirmed_channels:
raise InsufficientConfirmations(
'Insufficient confirmations for the channel '
'(sender=%s, open_block_number=%d)' %
(sender, open_block_number))
try:
c = self.channels[sender, open_block_number]
except KeyError:
raise NoOpenChannel('Channel does not exist or has been closed'
'(sender=%s, open_block_number=%s)' %
(sender, open_block_number))
if c.is_closed:
raise NoOpenChannel('Channel closing has been requested already.')
if not is_same_address(
verify_balance_proof(self.receiver, open_block_number, balance,
decode_hex(signature),
self.channel_manager_contract.address),
sender):
raise InvalidBalanceProof(
'Recovered signer does not match the sender')
return c
def sign_close(self, sender: str, open_block_number: int, balance: int):
"""Sign an agreement for a channel closing.
Returns:
channel close signature (str): a signature that can be used client-side to close
the channel by directly calling contract's close method on-chain.
"""
assert is_checksum_address(sender)
if (sender, open_block_number) not in self.channels:
raise NoOpenChannel('Channel does not exist or has been closed'
'(sender=%s, open_block_number=%d)' %
(sender, open_block_number))
c = self.channels[sender, open_block_number]
if c.is_closed:
raise NoOpenChannel('Channel closing has been requested already.')
assert balance is not None
if c.last_signature is None:
raise NoBalanceProofReceived('Payment has not been registered.')
if balance != c.balance:
raise InvalidBalanceProof(
'Requested closing balance does not match latest one.')
c.is_closed = True
c.mtime = time.time()
receiver_sig = sign_close(self.private_key, sender, open_block_number,
c.balance,
self.channel_manager_contract.address)
self.state.set_channel(c)
self.log.info(
'signed cooperative closing message (sender %s, block number %s)',
sender, open_block_number)
return receiver_sig
def verify_balance_proof(self, sender, open_block_number, balance,
signature):
"""Verify that a balance proof is valid and return the sender.
Does not check the balance itself.
:returns: the channel
"""
if (sender, open_block_number) in self.unconfirmed_channels:
raise InsufficientConfirmations(
'Insufficient confirmations for the channel '
'(sender=%s, open_block_number=%d)' %
(sender, open_block_number))
try:
c = self.channels[sender, open_block_number]
except KeyError:
print('NoOpenChannel key error')
raise NoOpenChannel('Channel does not exist or has been closed'
'(sender=%s, open_block_number=%s)' %
(sender, open_block_number))
if c.is_closed:
print('NoOpenChannel c.is_closed')
raise NoOpenChannel('Channel closing has been requested already.')
print('is_same_address', self.receiver, open_block_number, balance,
decode_hex(signature), sender)
if not is_same_address(
verify_balance_proof(self.receiver, open_block_number, balance,
decode_hex(signature)), sender):
raise InvalidBalanceProof(
'Recovered signer does not match the sender')
return c
def sign_close(self, sender, open_block_number, balance):
"""Sign an agreement for a channel closing."""
if (sender, open_block_number) not in self.channels:
raise NoOpenChannel('Channel does not exist or has been closed'
'(sender=%s, open_block_number=%d)' %
(sender, open_block_number))
c = self.channels[sender, open_block_number]
print('sign_close', c)
if c.is_closed:
raise NoOpenChannel('Channel closing has been requested already.')
assert balance is not None
# if c.last_signature is None:todo fix
# raise NoBalanceProofReceived('Payment has not been registered.')
if balance != c.balance:
raise InvalidBalanceProof(
'Requested closing balance does not match latest one.')
c.is_closed = True
c.mtime = time.time()
receiver_sig = sign_balance_proof(self.private_key, self.receiver,
open_block_number, balance)
self.state.store()
self.log.info(
'signed cooperative closing message (sender %s, block number %s)',
sender, open_block_number)
return receiver_sig
def register_payment(self, sender, open_block_number, balance, signature):
"""Register a payment."""
c = self.verify_balance_proof(sender, open_block_number, balance, signature)
if balance <= c.balance:
raise InvalidBalanceAmount('The balance must increase.')
if balance > c.deposit:
raise InvalidBalanceProof('Balance must not be greater than deposit.')
received = balance - c.balance
c.balance = balance
c.last_signature = signature
c.mtime = time.time()
self.state.store()
self.log.debug('registered payment (sender %s, block number %s, new balance %s)',
c.sender, open_block_number, balance)
return (c.sender, received)