Figment Datahub and Avalanche: Make an e-Voting dApp Using Figment Datahub, Avalanche, and Filebase

Learn make an e-Voting dApp Using Figment Datahub, Avalanche, and Filebase.

What is a dApp?

A dApp is a decentralized application that can operate autonomously, typically through the use of smart contracts, and runs on blockchain networks.

What is Figment DataHub?

Figment DataHub is a platform that enables developers to create decentralized applications (dApps) using the powerful and unique features of blockchain technology without having to be experts on the wide variety of blockchain protocols.

What is Avalanche?

Avalanche is a decentralized, open-source blockchain that has smart contract functionality.

In this guide, we’ll use Figment Datahub to create an API key that we’ll use to create a decentralized application on the Avalanche blockchain. We’ll also utilize S3FS-FUSE to mount a Filebase IPFS bucket locally to our system so that we can store our dApp source files.

Prerequisites:

• A crypto wallet, such as MetaMask.

• Install Node.js and npm.

• Add the Avalanche Network to your Crypto wallet

• Add test AVAX funds to your wallet using the Avalanche Faucet.

• Perform a cross-chain swap via the Transfer AVAX Between X-Chain and C-Chain tutorial to get funds to your C-Chain address on the Fuji testnet.

• Sign up for a free Filebase account.

This guide was written and tested using Ubuntu 20.04. Commands and workflow may vary depending on your operating system.

1. Login to your Figment Datahub console. Select ‘Create App’ to create a new Avalanche app.

2. Give your app a name, select ‘Staging’ for the environment, then select ‘Avalanche’ for the network.

Then use the ‘Create App’ button to create your new Avalanche app.

3. Once you’ve created your app, take note of the API key.

We will reference this API key later.

4. Next, we need a Filebase IPFS bucket.

To do this, navigate to console.filebase.com. If you don’t have an account already, sign up, then log in.

5. Select ‘Buckets’ from the left side bar menu, or navigate to console.filebase.com/buckets.

Select ‘Create Bucket’ in the top right corner to create a new bucket.

6. Enter a bucket name and choose the IPFS storage network to create the bucket.

Bucket names must be unique across all Filebase users, be between 3 and 63 characters long, and can contain only lowercase characters, numbers, and dashes.

7. Next, download and install S3FS-FUSE on a Linux or macOS system.

8. Set up an Access Key file for use with S3FS-FUSE.

Set up a credentials file for S3FS at ${HOME}/.passwd-s3fs. You will need to save your Filebase Access and Secret keys to this file and give it owner permissions. You can do so with the following commands:

echo ACCESS_KEY_ID:SECRET_ACCESS_KEY > ${HOME}/.passwd-s3fs

chmod 600 ${HOME}/.passwd-s3fs

ACCESS_KEY_ID is your Filebase Access key, and SECRET_ACCESS_KEY is your Filebase Secret key. For more information on Filebase access keys, see here.

9. Mount your bucket.

You can mount a Filebase IPFS bucket with the command:

s3fs mybucket /path/to/mountpoint -o passwd_file=${HOME}/.passwd-s3fs -o url=https://s3.filebase.com

• mybucket: name of your Filebase bucket

• /path/to/mountpoint

10. Now, navigate into the mounted Filebase bucket.

cd /path/to/mounted/bucket

11. Next, create a new folder to house your e-Voting app scripts and navigate inside of it.

mkdir evoting

cd evoting

12. Initialize your npm workspace:

npm init

13. Then install the required npm dependencies:

npm install express dotenv @truffle/hdwallet-provider --save

14. Next, initialize a boilerplate project with truffle:

truffle init

This command sets up our initial project structure, which includes a contracts folder that will house our smart contracts, and a migrations folder for deployment functions.

15. Open the truffle-config.js file that was created with the truffle init command. Replace the contents of that file with the following:

require('dotenv').config();
const HDWalletProvider = require("@truffle/hdwallet-provider");

//Account credentials from which our contract will be deployed
const mnemonic = process.env.MNEMONIC;

//API key of your Datahub account for Avalanche Fuji test network
const APIKEY = process.env.APIKEY;

module.exports = {
  networks: {
    fuji: {
      provider: function() {
            return new HDWalletProvider({mnemonic, providerOrUrl: `https://avalanche--fuji--rpc.datahub.figment.io/apikey/${APIKEY}/ext/bc/C/rpc`, chainId: "0xa869"})
      },
      network_id: "*",
      gas: 3000000,
      gasPrice: 470000000000,
      skipDryRun: true
    }
  },
  solc: {
    optimizer: {
      enabled: true,
      runs: 200
    }
  }
}

16. Next, create a .env file. In this file, we’ll need a few values:

• Create an account on the Avalanche network and enter your mnemonics in the .env file.

• Input your Avalanche API key that we took note of earlier.

The format is as follows:

MNEMONIC="avalanche-wallet-mnemonic"
APIKEY="your-api-key"

17. In the contracts directory, create a new file called Election.sol. In the file, enter the following content:

pragma solidity >=0.4.21 <0.6.0;

contract Election {
  //Structure of candidate standing in the election
  struct Candidate {
    uint id;
    string name;
    uint voteCount;
  }

  //Storing candidates in a map
  mapping(uint => Candidate) public candidates;

  //Storing address of those voters who already voted
  mapping(address => bool) public voters;

  //Number of candidates in standing in the election
  uint public candidatesCount;

  //Adding 2 candidates during the deployment of contract
  constructor () public {
    addCandidate("Filebase Robot");
    addCandidate("Figment Robot");
  }

  //Private function to add a candidate
  function addCandidate (string memory _name) private {
    candidatesCount ++;
    candidates[candidatesCount] = Candidate(candidatesCount, _name, 0);
  }

  //Public vote function for voting a candidate
  function vote (uint _candidate) public {
    require(!voters[msg.sender], "Voter has already Voted!");
    require(_candidate <= candidatesCount && _candidate >= 1, "Invalid candidate to Vote!");
    voters[msg.sender] = true;
    candidates[_candidate].voteCount++;
  }
}

This is a solidity smart contract that will allow us to view the candidates and their standing in the election.

18. Create a new file in the migration directory named 2_deploy_contracts.js. Enter the following code into this file:

const Election = artifacts.require("./Election.sol");

module.exports = function (deployer) {
  deployer.deploy(Election);
};

19. Then, compile the contracts with truffle:

truffle compile

Any time you make changes to the Election.sol file, you will need to recompile the contract.

20. Before deploying the contracts further, make sure your Avalanche wallet has enough funds.

Use the Avalanche Faucet to get more test funds for use.

21. Run the migrations to deploy your Election contract:

truffle migrate --network fuji

22. Now let’s move on to creating a simple UI for interacting with our e-Voting dApp. Create a new src directory and navigate inside of it.

mkdir src

cd src

23. Make a new server.js file and input the following code into the file:

var express = require('express');
var app = express();

//JSON file for deployed contract and network information
const electionJSON = require('../build/contracts/Election.json')

require("dotenv").config();

app.use(express.static("./"));

app.get('/', (req,res) => {
    res.send('index.html');
});

app.get('/electionJSON', (req,res) => {
    res.send(electionJSON);
});

app.listen(process.env.PORT || 3000, () => {
    console.log('Server started at 3000');
});

24. Make another new file called index.html with the following content:

<!DOCTYPE html>

<html lang="en">
  <head>
    <title>Election</title>
  </head>

  <link href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" rel="stylesheet">

  <body>
    <div style="width: 40%; margin: 50px auto" class="card">
            <!-- Account address will be rendered here -->
            <center id="account" style="margin-top: 20px"></center>

            <!-- Loading will appear until blockchain data is loaded -->
            <center id='loader' style="margin:20px;">Loading...</center>

            <br><br>

            <!-- Blockchain data would appear here -->
            <div id="content" style="display:none" class="container" style="margin-top:30px;">
                <!-- Table for fetching election data of the candidates -->
                <table class="table table-bordered">
                    <tr>
                        <td>#</td>
                        <td>Name</td>
                        <td>Votes</td>
                    </tr>
                    <tbody id="candidateResults">

                    </tbody>
                </table>

                <!-- Form to submit vote to a candidate -->
                <form onSubmit="App.castVote(); return false;" style="display:none">
                    <div class="form-group">
                        <label>Select Candidate</label>
                        <center>
                            <select class="form-control" id="candidatesSelect">
                                <option>Select here...</option>
                            </select><br>
                            <input type="submit" class="btn btn-primary" value="Vote">
                        </center>
                    </div>
                </form>

                <!-- This would appear and form will be hidden if the address has already voted -->
                <div id="hasVoted" style="display:none; text-align: center">
                    <b>Thank you for voting !!!</b>
                </div>
            </div>
        </div>
  </body>

  <!--jQuery CDN-->
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>

  <!--web3 module for interacting with blockchain-->
  <script language="javascript" type="text/javascript" src="https://cdn.jsdelivr.net/gh/ethereum/[email protected]/dist/web3.js"></script>

  <!--Truffle Contract module for interacting with smart contract in javascript-->
  <script src="https://rajranjan0608.github.io/ethereum-electionVoting/src/contract.js"></script>

  <!--Our custom javascript code for interaction-->
  <script type="module" language="javascript" src="index.js"></script>
</html>

You can change the styling of this code to reflect your candidate's names, different colors and themes, and even photos of each candidate.

25. Then, make another new file called index.js with the following content:

// App would contain all the necessary functions for interaction
var App = {
  loading: false,
  contracts: {},

  // Main function to be called first
  load: async () => {
    await App.loadWeb3();
    await App.loadAccount(); 
    await App.loadContract();
    await App.render();
  },

  // Loading web3 on the browser
  loadWeb3: async () => {
    if(typeof web3 !== 'undefined') {
      web3 = new Web3(web3.currentProvider);
      App.web3Provider = web3.currentProvider;
    }else {
      window.alert("Please connect to Metamask");
    }

    if(window.ethereum) {
      window.web3 = new Web3(ethereum);
      try {
        await ethereum.enable();
      }catch (error) {
        console.log(error);
      }
    }else if(window.web3) {
      App.web3Provider = web3.currentProvider;
      window.web3 = new Web3(web3.currentProvider);
    }else{
      console.log('Non-Ethereum Browser detected');
    }
  },

  // This function would load account from Metamask to our dApp
  loadAccount: async() => {
    await web3.eth.getAccounts().then((result)=>{
      App.account = result[0];
      console.log(App.account);
    });
  },

  // This function would help in loading contract to App.election
  loadContract: async () => {
    // Static pre-deployed contracts should be handled like this
    const election = await $.getJSON('/electionJSON');
    App.contracts.election = TruffleContract(election);
    App.contracts.election.setProvider(App.web3Provider);
    App.election = await App.contracts.election.deployed();
  },

  // This function will be called after the browser is ready for blockchain interaction
  render: async() => {
    if(App.loading) {
      return;
    }
    App.setLoading(true);
    $('#account').html(App.account);
    App.renderCandidates();
    App.setLoading(false);
  },

  // This will render blockchain data to the frontend.
  renderCandidates: async() => {
    var candidatesCount = await App.election.candidatesCount();

    $("#candidateResults").html("");
    $("#candidatesSelect").html("");

    for(var i=1; i <= candidatesCount; i++) {
      const candidate = await App.election.candidates(i);

      const id = candidate[0];
      const name = candidate[1];
      const voteCount = candidate[2];

      var candidateTemplate1 = "<tr>"+
                                  "<td>" + id + "</td>" +
                                  "<td>" + name + "</td>" +
                                  "<td>" + voteCount + "</td>" +
                              "</tr>";      
      $("#candidateResults").append(candidateTemplate1);

      var hasVoted = await App.election.voters(App.account);
      if(!hasVoted) {
        $("form").show();
        $("#hasVoted").hide();
      }else {
        $("#hasVoted").show();
        $("form").hide();
      }

      var candidateTemplate2 = "<option value='"+i+"'>" + name + "</option>";
      $("#candidatesSelect").append(candidateTemplate2);
    }
  },

  // This function will call vote() on Fuji testnet
  castVote: async() => {
    const candidateID = $("#candidatesSelect").val();
    await App.election.vote(candidateID, { from: App.account });
    App.renderCandidates();
  },

  setLoading: (boolean) => {
    App.loading = boolean;
    const loader = $('#loader');
    const content = $('#content');
    if(boolean) {
      loader.show();
      content.hide();
    }else {
      loader.hide();
      content.show();
    }
  }
};

// Driver function to initiate the blockchain interaction
$(() => {
  window.addEventListener('load', ()=>{
    App.load();
  });
});

window.App = App;

26. Start the e-Voting dApp with the following command:

node server.js

27. You can view your dApp at http://localhost:3000/ and interact with the webpage we created with the files in the src directory.

Congratulations! You’ve created an e-Voting app that is powered by blockchain and stored on decentralized storage!