not working

[ysrlin]

the result:https://basescan.org/tx/0x88a14f4ae349a3b789c4e308ce4b97f04bce12bb3594319115edaf67b77c9a91

the code:

def buy_usdc_from_v2_and_sell_to_v3():
    global transient_eth_balance
    # Wrap, Buy for 0.3 eth of usdc from v2, Sell to v3 and Unwrap
    v2_path = [weth_address, usdc_address]
    v2_in_amount = 5 * 10**14
    print(v2_in_amount / (10**18))
    v2_out_amount = 581526000  # with slippage
    v3_path = [usdc_address, 500, weth_address]
    v3_out_amount = int(2.98 * 10**17)  # with slippage
    encoded_input = (
        codec
        .encode
        .chain()
        .wrap_eth(FunctionRecipient.ROUTER, v2_in_amount)
        .v2_swap_exact_in(FunctionRecipient.ROUTER, v2_in_amount, v2_out_amount, v2_path, payer_is_sender=True)
        # .v3_swap_exact_in_from_balance(FunctionRecipient.ROUTER, v3_out_amount, v3_path)
        # .unwrap_weth(FunctionRecipient.SENDER, 0)
        .build(codec.get_default_deadline())
    )
    trx_hash = send_transaction(v2_in_amount, encoded_input)
    receipt = w3.eth.wait_for_transaction_receipt(trx_hash)
    assert receipt["status"] == 1, f'receipt["status"] is actually {receipt["status"]}'  # trx success

[Elnaril]

Hello @ysrlin
Just a quick comment, the following line is not correct:

.v2_swap_exact_in(FunctionRecipient.ROUTER, v2_in_amount, v2_out_amount, v2_path, payer_is_sender=True)

You should have payer_is_sender=False since the WETH tokens come from the router balance, and not your wallet.
Alternatively you can use this method: v2_swap_exact_in_from_balance()

[ysrlin]

I’ve made changes to the code, but it still doesn’t run correctly. I’ve tried both v2_swap_exact_in and v2_swap_exact_in_from_balance. The runtime results can be found at the following link.
https://basescan.org/tx/0x95852fea7300109dca92a4934c8f66be092dd081b8c7facdd563e1409f37d4f8
https://basescan.org/tx/0x4bb59bd205ffce3a25ca60cde4fd9d920501e405628ef2d22bda9c9b84d9fcfd
https://basescan.org/tx/0x8eb03282ef4767a2482d796af5062f278a59b8551b9f377cfad118308f516ee0

def buy_usdc_from_v2():
    v2_path = [weth_address, usdc_address]
    v2_in_amount = 5 * 10**14
    v2_out_amount = 3200 * 10**6  # with slippage
    encoded_input = (
        codec
        .encode
        .chain()
        .wrap_eth(FunctionRecipient.ROUTER, v2_in_amount)
        #https://basescan.org/tx/0x95852fea7300109dca92a4934c8f66be092dd081b8c7facdd563e1409f37d4f8
        .v2_swap_exact_in(FunctionRecipient.SENDER, v2_in_amount, v2_out_amount, v2_path, payer_is_sender=False)
        #https://basescan.org/tx/0x4bb59bd205ffce3a25ca60cde4fd9d920501e405628ef2d22bda9c9b84d9fcfd
        # .v2_swap_exact_in(FunctionRecipient.ROUTER, v2_in_amount, v2_out_amount, v2_path, payer_is_sender=False)
        #https://basescan.org/tx/0x8eb03282ef4767a2482d796af5062f278a59b8551b9f377cfad118308f516ee0
        # .v2_swap_exact_in_from_balance(FunctionRecipient.SENDER,v2_out_amount,v2_path)
        .build(codec.get_default_deadline())
    )
    trx_hash = send_transaction(v2_in_amount, encoded_input)
    receipt = w3.eth.wait_for_transaction_receipt(trx_hash)
    assert receipt["status"] == 1  # trx success
    # assert w3.eth.get_balance(account.address) < init_amount - total_in_amount
    bought_usdc = usdc_contract.functions.balanceOf(account.address).call()
    print(bought_usdc)
    print(" => BUY USDC: OK")

[Elnaril]

The decoded input of the transaction 0x95852fea7300109dca92a4934c8f66be092dd081b8c7facdd563e1409f37d4f8 is:

'decoded_input': {'commands': b'\x0b\x08',
                   'inputs': [(<Function WRAP_ETH(address,uint256)>,
                               {'recipient': '0x0000000000000000000000000000000000000002',
                                'amountMin': 500000000000000},
                               {'revert_on_fail': True}),
                              (<Function V2_SWAP_EXACT_IN(address,uint256,uint256,address[],bool)>,
                               {'recipient': '0x0000000000000000000000000000000000000001',
                                'amountIn': 500000000000000,
                                'amountOutMin': 3200000000,
                                'path': ['0x4200000000000000000000000000000000000006',
                                         '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'],
                                'payerIsSender': False},
                               {'revert_on_fail': True})],
                   'deadline': 1723855774}}

You try to swap 500000000000000 / 10**18 = 0.0005 WETH for 3200000000 / 10**6 = 3200 USDC.
At today's ETH price, I'm not surprised the transaction failed! 😉

Did you really mean this (WETH decimals is 18):

    v2_in_amount = 5 * 10**14
    v2_out_amount = 3200 * 10**6  # with slippage

[ysrlin]

The code is running properly now. Thank you so much. As a beginner, the mistakes you pointed out have helped me understand a lot. At the same time, I'm curious about how you managed to find the decoded_input：

'decoded_input': {'commands': b'\x0b\x08',
                   'inputs': [(<Function WRAP_ETH(address,uint256)>,
                               {'recipient': '0x0000000000000000000000000000000000000002',
                                'amountMin': 500000000000000},
                               {'revert_on_fail': True}),
                              (<Function V2_SWAP_EXACT_IN(address,uint256,uint256,address[],bool)>,
                               {'recipient': '0x0000000000000000000000000000000000000001',
                                'amountIn': 500000000000000,
                                'amountOutMin': 3200000000,
                                'path': ['0x4200000000000000000000000000000000000006',
                                         '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'],
                                'payerIsSender': False},
                               {'revert_on_fail': True})],
                   'deadline': 1723855774}}

[Elnaril]

@ysrlin: Happy I could help and thank you for your feedback! :)

To decode a Universal Router transaction input data, you can use one of the following method from the UR SDK:

codec.decode.function_input(trx_input) (see doc)

codec.decode.transaction(trx_hash) (see doc)

Happy coding!

BTW, would you mind marking the answer?