def transferERCToken(fromAddr, toAddr, amt, key, symbol):
try:
w3 = getW3()
availableBalance = getWalletTokenBalance(fromAddr, symbol)
if amt > availableBalance:
return 'Error: Not enough funds.'
contract_address = getTokenAddress(symbol)
abi_json = getContractAbiJson('ERC20')
abi = abi_json
erc20_token_contract = getContract(w3, abi, contract_address)
nonce = w3.eth.getTransactionCount(fromAddr)
amount = convertAmountToWei(symbol, amt)
transfer_tx = erc20_token_contract.functions.transfer(
toAddr, int(amount)).buildTransaction({
'chainId':
getChainId(), # 1 for mainnet, 3 for ropsten
'gas':
220920,
'gasPrice':
w3.toWei(150, 'gwei'),
'nonce':
nonce
})
signed_txn = w3.eth.account.sign_transaction(transfer_tx, key)
try:
tx_hash = w3.eth.sendRawTransaction(signed_txn.rawTransaction)
return w3.toHex(tx_hash)
except ValueError as err:
return 'Error: ' + str(err)
except Exception as ex:
return 'Error: ' + str(ex)
def approve(userAddress,
tokenSymbol,
smartContractAddress,
amountToApprove,
key,
protocol=''):
try:
if int(
amountToApprove
) < 1000000000: #avoid multiple approve charges but up to 1000 USDC
amountToApprove = 1000000000
w3 = getW3()
contract_address = getTokenAddress(tokenSymbol, protocol)
abi_json = getContractAbiJson('ERC20')
abi = abi_json
erc20_contract = getContract(w3, abi, contract_address)
nonce = w3.eth.getTransactionCount(userAddress)
appr_tx = erc20_contract.functions.approve(
Web3.toChecksumAddress(smartContractAddress),
int(amountToApprove)).buildTransaction({
'chainId':
getChainId(),
'gas':
2209200,
'gasPrice':
w3.toWei(150, 'gwei'),
'nonce':
nonce
})
signed_tx = w3.eth.account.signTransaction(appr_tx, key)
tx_hash = w3.eth.sendRawTransaction(signed_tx.rawTransaction)
return w3.toHex(tx_hash)
except Exception as ex:
return str(ex)
def getWalletTokenBalance(addr, erc20Token):
w3 = getW3()
contract_address = getTokenAddress(erc20Token)
abi_json = getContractAbiJson('ERC20')
abi = abi_json
erc20_token_contract = getContract(w3, abi, contract_address)
raw_balance = erc20_token_contract.functions.balanceOf(addr).call()
return convertAmountFromWei(erc20Token, raw_balance)
def getAmountsOut(self, token_symbol, token_amount):
# function getAmountsOut(uint amountIn, address[] memory path) internal view returns (uint[] memory amounts)
userToken = app.config['SYMB'] # token user owns
amount = convertAmountToWei(userToken, token_amount)
w3 = getW3()
abi_json = getContractAbiJson('UNI')
abi = abi_json['abi']
uniswap_contract = getContract(w3, abi, self.UNISWAP_CONTRACT_ADDR)
addressPaths = [Web3.toChecksumAddress(getTokenAddress(userToken, 'UNI')),
Web3.toChecksumAddress(getTokenAddress('WETH', 'UNI')),
Web3.toChecksumAddress(getTokenAddress(token_symbol, 'UNI'))]
amountsOut = uniswap_contract.functions.getAmountsOut(
int(amount), addressPaths).call()
return convertAmountFromWei(token_symbol, amountsOut[2])
def isApproved(userAddress,
tokenSymbol,
smartContractAddress,
amount,
protocol=''):
w3 = getW3()
contract_address = getTokenAddress(tokenSymbol, protocol)
abi_json = getContractAbiJson('ERC20')
abi = abi_json
erc20_contract = getContract(w3, abi, contract_address)
approved_amount = erc20_contract.functions.allowance(
userAddress, smartContractAddress).call()
return approved_amount >= amount
def tradeToken(self, token_symbol, token_amount):
userToken = app.config['SYMB'] # token user owns
availableBalance = getWalletTokenBalance(self.userWallet.address,
userToken)
if (availableBalance < token_amount):
return "Insuficent amount in your wallet"
uni_contract_address = self.UNISWAP_CONTRACT_ADDR
# convert in underlying token balance
amount = convertAmountToWei(userToken, token_amount)
if not isApproved(self.userWallet.address, userToken,
uni_contract_address, amount, 'UNI'):
approve(userWall.address, userToken, uni_contract_address, amount,
self.userWallet.privateKey, 'UNI')
w3 = getW3()
abi_json = getContractAbiJson('UNI')
abi = abi_json['abi']
uniswap_contract = getContract(w3, abi, uni_contract_address)
nonce = w3.eth.getTransactionCount(self.userWallet.address)
# function swapExactTokensForTokens
# uint amountIn,
# uint amountOutMin,
# address[] calldata path,
# address to,
# uint deadline
# ) external returns (uint[] memory amounts);
amountOutMin = int(
amount) * 0.0098 # __convertAmountToWei('DAI', amt/2)
addressPaths = [
Web3.toChecksumAddress(getTokenAddress(userToken, 'UNI')),
Web3.toChecksumAddress(getTokenAddress(token_symbol, 'UNI'))
]
# current_time = datetime.datetime.now(datetime.timezone.utc)
# unix_timestamp = current_time.timestamp() # works if Python >= 3.3
# deadline = int(unix_timestamp + (20 * 60)) # 20 minutes
deadline = int(time.time()) + 10000
trade_tx = uniswap_contract.functions.swapExactTokensForTokens(
int(amount), int(amountOutMin), addressPaths,
self.userWallet.address, deadline).buildTransaction({
'chainId':
getChainId(),
'gas':
5000000,
'gasPrice':
w3.toWei('20', 'gwei'),
'nonce':
nonce
})
signed_txn = w3.eth.account.sign_transaction(
trade_tx, self.userWallet.privateKey)
try:
tx = w3.eth.sendRawTransaction(signed_txn.rawTransaction)
# return tx.hex()
try:
txn_receipt = w3.eth.waitForTransactionReceipt(tx, timeout=300)
except Exception:
return {'status': 'failed', 'error': 'timeout'}
else:
return {'status': 'success', 'receipt': txn_receipt}
except ValueError as err:
# return (json.loads(str(err).replace("'", '"')), 402, {'Content-Type': 'application/json'})
return 'Error: ' + str(err)