Swap Tokens with GoSwap with web3

[er1202]

Hello,

i'm trying to swap some tokens over GoSwap with web3.js or web3.py. As i have seen does gochain web3 not have a function like this.
Is there a "routing contract" involved like on uniswap or how could i do this. I think i have to swap GO's to WGO's first but i can't find a pair for that.

I'm sure the solution is somewhere here but i need a few example code lines with which i can start

Maybe anyone can help me - thank you...

[er1202]

I think i found a few lines of sample code but i don't know the address of the router contract. Where can i find this.

[er1202]

Yes it does... So wrapping, unwrapping, and shaping from OMI to WGO works perfekt...
Hopefully the last question in this matter is to SWAP from OMI to WGO...
I use: swapExactTokensForTokens(amountIn, amountOutMin, [OmiTokenAddress, WGoTokenAddress]),accountaddress, timeValid) for swapping OMI to WGO but it doesn't work the other way:
WGO to OMI
swapExactTokensForTokens(amountIn, amountOutMin, [WGoTokenAddress, OmiTokenAddress]),accountaddress, timeValid)
Any idea what's wrong here...

[er1202]

I'm still working (or freaking out) on the problem that i'm able to swap from OMI to WGO but not the other direction...
Could this be a problem with fee's or to i have to send some WGO (GO's whatever) to the contract before the swap???
I see only that the transaction is failed on the GoChainExplorer, without any details 0x001d80f8662bb6429a9f1d0f57243c81505f4500677e2001a941c10790cac827

This is my python.code:
`swap_txn = router.functions.swapExactTokensForTokens(web3.toWei(int(amount), 'ether'),
web3.toWei(int(AmountOutMin), 'ether'),
[WGoTokenAddress,OmiTokenAddress],
MetaMaskAddress,
ValidTime).buildTransaction(
{'nonce': nonce, 'gas': 139071, 'gasPrice': web3.eth.gas_price})

[treeder]

Some googling:

• https://ethereum.stackexchange.com/questions/96847/uniswap-pancakeswap-swap-swapexacttokensfortokens-swapexactethfortokens-failed
• https://stackoverflow.com/questions/66404029/web3-py-swapexacttokensfortokens-failing-transaction

[er1202]

Thanks for your answer, unfortunately i have seen these pages before...

1. I don't think that i have to less gas. As you see in my transaction gas limit is 139,071 gas used is 37,198 OK?
2. I also tried the swapExactETHForTokens functions but it ditn't work (i have OMI, GO and WGO on my account)
3. I'm not sure how i should work with the aprove() function ??????
4. I tried to put the 'from' field into the buildTransaction with my MetaMask address (correct?) but still don't work

I don't understand that the other direction works without any problems, do you think i need the aprove function (if so, how to use?)

[er1202]

approved it in MetaMask -> now it works... (costs me only 10hours ;-)

[treeder]

Answers from discussion:

Router: 0x3881e447F439891dC106Da7bca0007B319eeB74D

Wrapped GO (wGO) contract: 0xcC237fa0A4B80bA47992d102352572Db7b96A6B5 (which is the standard gnosis contract)

Be sure to call approve() function before attempting swaps.