def get_channel_participants_from_open_event(
token_network: "TokenNetwork",
channel_identifier: ChannelID,
contract_manager: ContractManager,
from_block: BlockNumber,
) -> Optional[Tuple[Address, Address]]:
# For this check it is perfectly fine to use a `latest` block number.
# Because the filter is looking just for the OPENED event.
to_block = "latest"
filter_args = get_filter_args_for_specific_event_from_channel(
token_network_address=token_network.address,
channel_identifier=channel_identifier,
event_name=ChannelEvent.OPENED,
contract_manager=contract_manager,
from_block=from_block,
to_block=to_block,
)
events = token_network.proxy.contract.web3.eth.getLogs(filter_args)
# There must be only one channel open event per channel identifier
if len(events) != 1:
return None
event = decode_event(
contract_manager.get_contract_abi(CONTRACT_TOKEN_NETWORK), events[0])
participant1 = Address(decode_hex(event["args"]["participant1"]))
participant2 = Address(decode_hex(event["args"]["participant2"]))
return participant1, participant2
def test_get_filter_args(contract_manager):
channel_identifier = factories.UNIT_CHANNEL_ID
token_network_address = factories.UNIT_TOKEN_NETWORK_ADDRESS
event_filter_params = get_filter_args_for_all_events_from_channel(
token_network_address=token_network_address,
channel_identifier=channel_identifier,
contract_manager=contract_manager,
)
assert event_filter_params["topics"][0] is None
assert to_int(
hexstr=event_filter_params["topics"][1]) == channel_identifier
assert event_filter_params["address"] == to_checksum_address(
token_network_address)
assert event_filter_params["fromBlock"] == 0
assert event_filter_params["toBlock"] == BLOCK_ID_LATEST
with pytest.raises(ValueError):
# filter argument generation checks if event type is known
get_filter_args_for_specific_event_from_channel(
token_network_address=token_network_address,
channel_identifier=channel_identifier,
event_name="NonexistingEvent",
contract_manager=contract_manager,
)
event_filter_params = get_filter_args_for_specific_event_from_channel(
token_network_address=token_network_address,
channel_identifier=channel_identifier,
event_name="ChannelOpened",
contract_manager=contract_manager,
from_block=BlockNumber(100),
to_block=BlockNumber(200),
)
assert event_filter_params["topics"][0] is not None
assert to_int(
hexstr=event_filter_params["topics"][1]) == channel_identifier
assert event_filter_params["address"] == to_checksum_address(
token_network_address)
assert event_filter_params["fromBlock"] == 100
assert event_filter_params["toBlock"] == 200
def settle_timeout(self) -> BlockTimeout:
""" Returns the channels settle_timeout. """
# There is no way to get the settle timeout after the channel has been closed as
# we're saving gas. Therefore get the ChannelOpened event and get the timeout there.
filter_args = get_filter_args_for_specific_event_from_channel(
token_network_address=self.token_network.address,
channel_identifier=self.channel_identifier,
event_name=ChannelEvent.OPENED,
contract_manager=self.contract_manager,
)
events = self.client.web3.eth.getLogs(filter_args)
assert len(events) > 0, "No matching ChannelOpen event found."
# we want the latest event here, there might have been multiple channels
event = decode_event(
self.contract_manager.get_contract_abi(CONTRACT_TOKEN_NETWORK),
events[-1])
return event["args"]["settle_timeout"]
def close_block_number(self) -> Optional[BlockNumber]:
""" Returns the channel's closed block number. """
# The closed block number is not in the smart contract storage to save
# gas. Therefore get the ChannelClosed event is needed here.
filter_args = get_filter_args_for_specific_event_from_channel(
token_network_address=self.token_network.address,
channel_identifier=self.channel_identifier,
event_name=ChannelEvent.CLOSED,
contract_manager=self.contract_manager,
)
events = self.token_network.proxy.contract.web3.eth.getLogs(
filter_args)
if not events:
return None
assert len(events) == 1
event = decode_event(
self.contract_manager.get_contract_abi(CONTRACT_TOKEN_NETWORK),
events[0])
return event["blockNumber"]
