Timeline for Swap tokens back to ether on Uniswap V2 Router 02 (Sell tokens)
Current License: CC BY-SA 4.0
16 events
| when toggle format | what | by | license | comment | |
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| Jul 1, 2020 at 5:47 | comment | added | gbenroscience | Here is the working transaction: kovan.etherscan.io/tx/… | |
| Jul 1, 2020 at 4:58 | comment | added | the_cranky_panda | No problem What was the issue, out of curiosity? | |
| Jul 1, 2020 at 4:30 | comment | added | gbenroscience | Alright thanks for your help, I finally got it working. | |
| Jul 1, 2020 at 4:15 | comment | added | the_cranky_panda | Your original question was about "Fail with error 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT. What could be the issue, please?'" which I answered and solved, not "I can't made a uniswap trade, please help me get working code" :) The other error should have been a separate question technically | |
| Jul 1, 2020 at 3:58 | comment | added | gbenroscience | Hi, I didnt mark it as answered because all the tests I ran on my code using your suggestions didnt work, so I have no way of knowing if the question is answered or not. Anyway, if you were writing my code for me, you would have provided a working example of how to do the swap in your answer but you didnt. I spent valuable hours trying to glean out details from you, so dont blame me for not accepting your answer. Anyway, I give you the benefit of the doubt that I am the one not doing something right on my end. | |
| Jul 1, 2020 at 3:52 | vote | accept | gbenroscience | ||
| Jul 1, 2020 at 3:31 | comment | added | the_cranky_panda |
Oops, I meant that you should do approve(address(usi), amount) not approve(address(this), amount). Anyway, the original question has been answered and I'm basically writing your code for you at this point so could you mark the question as answered please
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| Jun 30, 2020 at 22:41 | comment | added | gbenroscience |
It still failed with the same error after I added the code to approve. The dai_address in IERC20 dai = IERC20(dai_address) , is it same as the crypto address passed to the parameter in my example? Please see my edit to the question
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| Jun 30, 2020 at 21:53 | comment | added | the_cranky_panda | Definitely before :) | |
| Jun 30, 2020 at 19:57 | comment | added | gbenroscience | Thanks a lot. One more thing though, will I do the approval before or after the call to swapExactTokensForEth? | |
| Jun 30, 2020 at 19:24 | comment | added | the_cranky_panda |
You can't interact with UniswapV2Router2 to change the allowance amount in the Dai contract, you have to call the Dai contract itself. You need an ERC20 interface like github.com/Uniswap/uniswap-v2-periphery/blob/master/contracts/… and have IERC20 dai = IERC20(dai_address); dai.approve(address(this), amount_to_approve);
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| Jun 30, 2020 at 19:08 | comment | added | gbenroscience | I figured as much but I haven't done this before using Uniswap v2 Router02. Can you show a sample that will help with this? | |
| Jun 30, 2020 at 19:05 | comment | added | the_cranky_panda |
I think it's because you haven't called approve on the Dai contract that will allow UniswapV2Router2 to withdraw your Dai and deposit it in to the Dai/Eth pair. You need to do dai.approve(address_of_your_contract, large_uint) Btw if you're using mainnet or a testnet, you can use dashboard.tenderly.co/explorer and it'll show you the code of the error
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| Jun 30, 2020 at 18:50 | comment | added | gbenroscience | please check my edit | |
| Jun 30, 2020 at 18:41 | comment | added | gbenroscience | I changed it to getAmountsOut, now it says: Fail with error 'TransferHelper: TRANSFER_FROM_FAILED' kovan.etherscan.io/tx/… | |
| Jun 30, 2020 at 17:39 | history | answered | the_cranky_panda | CC BY-SA 4.0 |