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I am using Flask at the backend and ganache for my blockchain project. I am also using Metamask. My smart contract is on the remix website. And here is my contract:

pragma solidity ^0.4.21; contract Election{ struct Candidate { uint voteCount; string name; } struct voter { bool authorized; bool voted; uint vote; } address public owner; string public electionName; mapping(address => voter) public voters; Candidate[] public candidates; uint public totalVotes; modifier ownerOnly() { require(msg.sender == owner); _; } constructor(string _name) public { owner = msg.sender; electionName = _name; } function addCandidate(string _name) ownerOnly public { candidates.push(Candidate(0, _name)); } function getNumCandidates() public view returns(uint) { return candidates.length; } function authorize(address _person) ownerOnly public { voters[_person].authorized = true; } function vote(uint _voteIndex) public { require(!voters[msg.sender].voted); require(voters[msg.sender].authorized); voters[msg.sender].vote = _voteIndex; voters[msg.sender].voted = true; candidates[_voteIndex].voteCount += 1; totalVotes += 1; } function end() ownerOnly public { selfdestruct(owner); } }

I am facing a problem with Vote function. When I run this whole contract after deploying on the remix website it is working fine. But when I am making transaction from my flask based app there is revert error even after having the voter in Voters list. So using metamask I want to make my transaction for voting. I deploy the contract with a default account.

w3 = Web3(HTTPProvider('http://127.0.0.1:7545')) w3.eth.defaultAccount = w3.eth.accounts[0] contract = w3.eth.contract(address=address, abi=data["abi"]) tx_hash = contract.functions.vote(candidate_index).transact() w3.eth.wait_for_transaction_receipt(tx_hash)

Now I want to make transactions from the account which I choose in Metamask. Because the above method is not working. Is there any way or any example to do it? I also visited metamask documentation where the use of ethereum.request() is suggested. But I was unable to implement it in web3py.

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Your code is correct. There are 2 require statements in vote. I think that is why you are getting the error. You can add custom message to require functions so you can see which one is causing the error:

 require(!voters[msg.sender].voted,"You already voted"); require(voters[msg.sender].authorized,"You are not authorized");

I believe since you already call vote with your default account, you are not passing the first require statement.

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Because I am using account 0 as default account and I deploy contract on remix with injected web3. At First I authorize account 1 and 2 as voters. Then on remix I change account 1 for transaction and this cause metamask popup and I select the account 1.
Then I try to vote and I get a revert error. So how I can make my transaction such that when I try to vote then I can choose the account to make transaction from metamask wallet. And when I choose the account and confirm the transaction the vote gets done. I am using web3.py

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