def __call_by_default(self, args):
function_abi = find_matching_fn_abi(self._function.contract_abi,
self._function.web3.codec,
fn_identifier=self._function.function_identifier,
args=args)
return function_abi['constant'] if 'constant' in function_abi.keys() else False
def _set_function_info(self):
if not self.abi:
self.abi = find_matching_fn_abi(self.contract_abi,
self.function_identifier,
self.args, self.kwargs)
if self.function_identifier is FallbackFn:
self.selector = encode_hex(b'')
elif is_text(self.function_identifier):
self.selector = encode_hex(function_abi_to_4byte_selector(
self.abi))
else:
raise TypeError("Unsupported function identifier")
self.arguments = merge_args_and_kwargs(self.abi, self.args,
self.kwargs)
def _find_matching_fn_abi(cls, fn_identifier=None, args=None, kwargs=None):
return find_matching_fn_abi(cls.abi,
fn_identifier=fn_identifier,
args=args,
kwargs=kwargs)
def call_contract_function(web3,
address,
normalizers,
function_identifier,
transaction,
block_id=None,
contract_abi=None,
fn_abi=None,
*args,
**kwargs):
"""
Helper function for interacting with a contract function using the
`eth_call` API.
"""
call_transaction = prepare_transaction(
address,
web3,
fn_identifier=function_identifier,
contract_abi=contract_abi,
fn_abi=fn_abi,
transaction=transaction,
fn_args=args,
fn_kwargs=kwargs,
)
if block_id is None:
return_data = web3.eth.call(call_transaction)
else:
return_data = web3.eth.call(call_transaction,
block_identifier=block_id)
if fn_abi is None:
fn_abi = find_matching_fn_abi(contract_abi, function_identifier, args,
kwargs)
output_types = get_abi_output_types(fn_abi)
try:
output_data = decode_abi(output_types, return_data)
except DecodingError as e:
# Provide a more helpful error message than the one provided by
# eth-abi-utils
is_missing_code_error = (return_data in ACCEPTABLE_EMPTY_STRINGS
and web3.eth.getCode(address)
in ACCEPTABLE_EMPTY_STRINGS)
if is_missing_code_error:
msg = (
"Could not transact with/call contract function, is contract "
"deployed correctly and chain synced?")
else:
msg = (
"Could not decode contract function call {} return data {} for "
"output_types {}".format(function_identifier, return_data,
output_types))
raise BadFunctionCallOutput(msg) from e
_normalizers = itertools.chain(
BASE_RETURN_NORMALIZERS,
normalizers,
)
normalized_data = map_abi_data(_normalizers, output_types, output_data)
if len(normalized_data) == 1:
return normalized_data[0]
else:
return normalized_data
