def build_transaction_for_function(address,
web3,
function_name=None,
transaction=None,
contract_abi=None,
fn_abi=None,
*args,
**kwargs):
"""Builds a dictionary with the fields required to make the given transaction
Don't call this directly, instead use :meth:`Contract.buildTransaction`
on your contract instance.
"""
prepared_transaction = prepare_transaction(
address,
web3,
fn_identifier=function_name,
contract_abi=contract_abi,
fn_abi=fn_abi,
transaction=transaction,
fn_args=args,
fn_kwargs=kwargs,
)
prepared_transaction = fill_transaction_defaults(web3,
prepared_transaction)
return prepared_transaction
def transact_with_contract_function(address,
web3,
function_name=None,
transaction=None,
contract_abi=None,
fn_abi=None,
*args,
**kwargs):
"""
Helper function for interacting with a contract function by sending a
transaction.
"""
transact_transaction = prepare_transaction(
address,
web3,
fn_identifier=function_name,
contract_abi=contract_abi,
transaction=transaction,
fn_abi=fn_abi,
fn_args=args,
fn_kwargs=kwargs,
)
txn_hash = web3.eth.sendTransaction(transact_transaction)
return txn_hash
def estimate_gas_for_function(address,
web3,
fn_identifier=None,
transaction=None,
contract_abi=None,
fn_abi=None,
*args,
**kwargs):
"""Estimates gas cost a function call would take.
Don't call this directly, instead use :meth:`Contract.estimateGas`
on your contract instance.
"""
estimate_transaction = prepare_transaction(
address,
web3,
fn_identifier=fn_identifier,
contract_abi=contract_abi,
fn_abi=fn_abi,
transaction=transaction,
fn_args=args,
fn_kwargs=kwargs,
)
gas_estimate = web3.eth.estimateGas(estimate_transaction)
return gas_estimate
def _prepare_transaction(cls,
fn_name,
fn_args=None,
fn_kwargs=None,
transaction=None):
return prepare_transaction(
cls.address,
cls.web3,
fn_identifier=fn_name,
contract_abi=cls.abi,
transaction=transaction,
fn_args=fn_args,
fn_kwargs=fn_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