web3_py_issue_739.py

import time
import web3

from solc import compile_source

from web3 import Web3, EthereumTesterProvider

contract_source = '''
pragma solidity ^0.4.18;

contract WETH9 {
    string public name     = "Wrapped Ether";
    string public symbol   = "WETH";
    uint8  public decimals = 18;

    event  Approval(address indexed src, address indexed guy, uint wad);
    event  Transfer(address indexed src, address indexed dst, uint wad);
    event  Deposit(address indexed dst, uint wad);
    event  Withdrawal(address indexed src, uint wad);

    mapping (address => uint)                       public  balanceOf;
    mapping (address => mapping (address => uint))  public  allowance;

    function() public payable {
        deposit();
    }
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
        Deposit(msg.sender, msg.value);
    }
    function withdraw(uint wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
        Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint) {
        return this.balance;
    }

    function approve(address guy, uint wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
        Approval(msg.sender, guy, wad);
        return true;
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        require(balanceOf[src] >= wad);

        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }

        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

        Transfer(src, dst, wad);

        return true;
    }
}
'''

def wait_on_tx_receipt(tx_hash):
    start_time = time.time()
    while True:
        if start_time + 60 < time.time():
            raise TimeoutError("Timeout occurred waiting for tx receipt")
        if w3.eth.getTransactionReceipt(tx_hash):
            return w3.eth.getTransactionReceipt(tx_hash)

compiled_sol = compile_source(contract_source)
contract_interface = compiled_sol['<stdin>:WETH9']

contract_abi = contract_interface['abi']
contract_code = contract_interface['bin']

w3 = Web3(EthereumTesterProvider())

contract = w3.eth.contract(
    abi=contract_abi,
    bytecode=contract_code)


tx_hash = contract.constructor().transact(
    transaction={
        'from': w3.eth.accounts[0],
        'gas': 410000})

tx_receipt = w3.eth.getTransactionReceipt(tx_hash)
contract_address = tx_receipt['contractAddress']

# Instatiate contract
WETH9 = w3.eth.contract(address=contract_address, abi=contract_interface['abi'])

# Create log filter instance
_filter = WETH9.events.Deposit.createFilter(fromBlock=0)

# Event emitting transaction
tx_hash = WETH9.functions.deposit().transact()

# Wait for transaction to be mined
receipt = wait_on_tx_receipt(tx_hash)

# Poll filter
print(_filter.get_new_entries())