web3.py getAmountOut() 输出 INVALID LIQUIDITY

Question

I'm trying to use the getAmountOut() function from the Uniswap Router-02 which should tell you how much of output token you should receive for a given input token amount.

Problem is I am getting the following error:

web3.exceptions.ContractLogicError: execution reverted: UniswapV2Library: INSUFFICIENT_LIQUIDITY .

Now does this function require you to use some ETH because it has to pay gas fees in order to execute or is there an error in my code?

def checkSubTrade(exchange, in_token_address, out_token_address, amount):

# Should be general cross exchange but would have to check if each routers contain the same methods
router_address = w3.toChecksumAddress(router_dict[str(exchange)])
router_abi = abi_dict[str(exchange)]
router_contract = w3.eth.contract(address = router_address, abi = router_abi)
swap_path = [in_token_address, out_token_address]

output = router_contract.functions.getAmountsOut(amount, swap_path).call()

return output

output = checkSubTrade('uniswap', token_dict['WETH'], token_dict['UNI'], 100000000)
print(output())

token_dict , router_dict contain the addresses and abi_dict contains the ABI for the DEX.

Answer 1

i think you need to check two things.

1. router_address: maybe it is different then you think when you go scope page that chain providing, you can see transaction detail. and there is from and to, for example this link you might see the to, in swap session to is route_address. so like that, you need to search in scope page to get route_address
2. router_abi: i think you using uniswapv2library, but in uniswap2library there is many other abi. for example factoryabi. so you need to check abi is correct or not. i highly recommend that you need to get or make solidity file of abi and change abi via web ide