Creating a Cryptocurrency Wallet using GetBlock and Web3.js | Code Eater – Blockchain | English

Creating a Mini Decentralized Wallet with Web3.js

Welcome back to Code Eater! In today’s video, we will learn how to create our own mini decentralized wallet using Web3.js. We will generate random account addresses, similar to Metamask, and generate private keys from these addresses. Additionally, we will create our own transactions, learn how to sign them, and finally transfer ether from a sender to a receiver. Let’s dive into the exciting world of decentralized wallets!

Setting Up the Development Environment

To get started, open your Visual Studio Code editor and create a new file called “mini-wallet.js” in a new folder. Before we begin coding, we need to install some dependencies. Open your terminal and run the following commands:

npm init -y
npm install web3
npm install dotenv

The first command initializes a new npm project and creates a package.json file. The second command installs the web3.js library, which we will use to interact with the ethereum blockchain. The third command installs the dotenv package, which allows us to securely store API keys and private keys.

Now that we have our dependencies installed, let’s start coding our mini decentralized wallet!

Connecting to the Blockchain Network

In order to connect our computer to the blockchain network, we need a medium that acts as a bridge between the real world and the blockchain world. We will use GetBlock.io as our bridge. GetBlock.io provides APIs that allow our computer to communicate with the blockchain.

To get started, go to the GetBlock.io website and create an account. Once you’re logged in, generate an API key for your project. Copy the API key and create a new file called “.env” in your project folder. Inside the .env file, add the following:

API_KEY=YOUR_API_KEY
PRIVATE_KEY=YOUR_PRIVATE_KEY
NETWORK=goerli
NODE=https://YOUR_NODE_URL

Replace “YOUR_API_KEY” with your actual API key from GetBlock.io. Similarly, replace “YOUR_PRIVATE_KEY” with your Ethereum account’s private key. The NETWORK variable specifies the Ethereum network we want to connect to (in this case, Goerli test network). Finally, replace “YOUR_NODE_URL” with the JSON-RPC URL provided by GetBlock.io for the Goerli network.

In your JavaScript code, import the dotenv and web3 modules:

require('dotenv').config();
const Web3 = require('web3');

Next, create an instance of the Web3 object and connect it to the Ethereum network:

const web3 = new Web3(process.env.NODE);

Now, if you log the web3 object, you should see a valid instance of the Web3 object, indicating a successful connection to the blockchain network.

Generating Random Account Addresses

Similar to Metamask, we want our mini decentralized wallet to be able to generate random account addresses. To do this, we can use the web3.eth.accounts.create() method:

const account = web3.eth.accounts.create();
console.log(account.address);

This code will generate a random Ethereum account address and log it to the console. You can run the script to see the generated address.

Generating Private Key from Account Address

In addition to generating account addresses, we also want to generate private keys from these addresses. This is necessary for signing transactions. To generate a private key from an account address, we can use the web3.eth.accounts.privateKeyToAccount() method:

const privateKey = process.env.PRIVATE_KEY;
const accountFrom = web3.eth.accounts.privateKeyToAccount(privateKey);
console.log(accountFrom.address);

Replace “PRIVATE_KEY” with the actual private key from your .env file. This code will generate an account address from the provided private key and log it to the console. You can run the script to see the generated address.

Signing and Sending Transactions

Now that we have our account addresses and private keys, we can proceed to sign and send transactions. First, let’s create a function to sign transactions:

async function signTransaction(rawTransaction) {
  const gas = await web3.eth.estimateGas(rawTransaction);
  return await accountFrom.signTransaction(rawTransaction);
}

This function takes a raw transaction object as input and estimates the gas required for the transaction. It then signs the transaction using the private key associated with the “accountFrom” address.

Next, let’s create a function to send the signed transaction:

async function sendTransaction(signedTransaction) {
  return await web3.eth.sendSignedTransaction(signedTransaction.rawTransaction);
}

This function takes the signed transaction object as input and sends it to the Ethereum network for processing.

Now, let’s create a raw transaction to send some ether from one account to another:

const to = '0x1234567890abcdef1234567890abcdef12345678';
const value = web3.utils.toWei('0.01', 'ether');
const rawTransaction = {
  from: accountFrom.address,
  to: to,
  value: value,
  gas: gas,
};

Replace “0x1234567890abcdef1234567890abcdef12345678” with the actual account address you want to send ether to. The “value” variable represents the amount of ether to send (in this case, 0.01 ether).

Finally, let’s sign and send the transaction:

const signedTransaction = await signTransaction(rawTransaction);
const receipt = await sendTransaction(signedTransaction);
console.log(receipt);

This code signs the raw transaction using the “signTransaction” function and sends the signed transaction using the “sendTransaction” function. The receipt object contains information about the transaction, such as the transaction hash and block number.

Run the script to send the transaction. You can check the transaction details on a blockchain explorer like Etherscan.io using the transaction hash provided in the receipt object.

Frequently Asked Questions (FAQs)

1. How do I generate a random account address?

To generate a random account address, you can use the web3.eth.accounts.create() method. This will create a new Ethereum account with a random address and private key.

2. How do I generate a private key from an account address?

To generate a private key from an account address, you can use the web3.eth.accounts.privateKeyToAccount() method. This method takes the private key as input and returns an account object with the associated address.

3. How do I sign a transaction?

To sign a transaction, you can use the account object’s signTransaction() method. This method takes a raw transaction object as input and returns a signed transaction object.

4. How do I send a signed transaction to the Ethereum network?

To send a signed transaction to the Ethereum network, you can use the web3.eth.sendSignedTransaction() method. This method takes the signed transaction object as input and sends it to the network for processing.

5. How do I estimate the gas required for a transaction?

To estimate the gas required for a transaction, you can use the web3.eth.estimateGas() method. This method takes a raw transaction object as input and returns the estimated gas value.

That’s it! You have successfully created your own mini decentralized wallet using Web3.js. You can now generate random account addresses, generate private keys from these addresses, sign transactions, and send ether from one account to another. Happy coding!