A Basic Smart Contract Developer Course

Smart contracts are self-executing computer programs that instantly carry out a contract's conditions. They are tamper-proof, transparent, and safe since they are stored on a blockchain network. Decentralized autonomous organizations (DAOs), crowdfunding platforms, and digital asset exchanges are just a few examples of the numerous industries that have utilized smart contracts to transform their processes.

In this basic smart contract developer course, we'll explore the foundations of smart contract development and take you through some easy steps to creating your first smart contract.

Understanding Blockchain

It's important to have a fundamental understanding of blockchain technology before getting started with smart contract development. A blockchain is a decentralized ledger that securely and openly records transactions. It is simply a digital database of transactions that is duplicated and distributed across the whole network of computer systems connected to a blockchain network. Every time a new transaction takes place on the blockchain, a record of that transaction is added to each participant's ledger and it cannot be changed or removed. The blockchain is maintained by a network of computers known as nodes.

The Bitcoin blockchain, which was developed to enable safe and decentralized bitcoin transactions, is the most popular blockchain. Since its inception, several industries have embraced blockchain technology to develop blockchain applications. The emergence of bitcoin has also inspired the creation of other cryptocurrencies known as “altcoins" in the cryptocurrency market.

What is Ethereum?

Ethereum is a scalable, programmable, secure, and decentralized blockchain network It is the most commonly used blockchain by developers and enterprises to develop innovative blockchain-based solutions. Unlike Bitcoin, which is made exclusively for digital money transactions, Ethereum is intended to be a blockchain platform for building various applications and use cases.

The computational resources needed to process transactions and carry out smart contracts are paid for using the Ethereum network's digital currency, called Ether (ETH).

Introduction to Solidity

Solidity is the programming language that is used to create smart contracts on the Ethereum network. It is a high-level programming language that takes inspiration from some popular programming languages like C++, JavaScript, and Python. It's a simple program for developers to read and write.

Some popular DeFi projects that utilize Solidity for developing their smart contract applications are UniSwap, SushiSwap, and Aave.

In this smart contract developer course, we will write our first smart contract in Solidity and deploy it to the Ethereum network.

Setting up Your Development Environment

Setting up our development environment is necessary before we can start developing our smart contract. Here's how to set up a development environment for writing smart contracts;

1. Install a code editor: A code editor is the major tool you'll be using to write your smart contracts. Some popular picks include Visual Studio Code and Atom. You can download and install these programs for free.

2. Launch the Solidity compiler: You'll need to install a Solidity compiler to turn your code into something that can run on the blockchain. One popular option is Remix, which is an online Solidity compiler that you can access through your web browser. You can also download and install a local compiler if you prefer to.

3. Install a local blockchain: To test your contracts, you'll need to set up a local blockchain. One popular option is to use a local Ethereum blockchain like Ganache. This will allow you to test your contracts on your own computer before you deploy them on the live Ethereum network. You can download Ganache from the official website to get started.

4. Download a wallet: A wallet is a program that allows you to store, send, and receive cryptocurrency. You'll need a wallet to deploy your contracts on the Ethereum network. You can use a common option like MetaMask, which is available as a browser extension and mobile app. To install MetaMask, go to the official website and follow the instructions to set it up.

5. Get some Ether: Ether is the cryptocurrency used to pay for transactions on the Ethereum network. You'll need some real ether and testnet ether in your wallet to deploy your contracts and test it. You can get some test ether from Alchemy.

How to Write your First Smart Contract

Now that you have set up our development environment, you are ready to start writing your first smart contract. Here are the steps to take.

1. You need to define the contract structure. Input this code in your code editor:

pragma solidity ^0.8.0;

contract FirstContract {

}

2. Define some variables. You can define variables within the contract. For example, you might want to define a variable for storing the contract's balance. Add this in your code editor :

pragma solidity ^0.8.0;

contract FirstContract {

    uint256 public balance;

}

It is important to only use the appropriate data type for each variable. For example, you should use "address" data type for storing Ethereum addresses and "uint256" for storing positive numbers.

3. Define Functions. Functions in Solidity are used to perform specific actions. You can define functions to perform various actions like sending funds to another address or updating the contract's variables. 

For instance, you can define a function to deposit funds into the contract's balance with this:

pragma solidity ^0.8.0;

contract FirstContract {

    uint256 public balance;

    function deposit() public payable {

        balance += msg.value;

    }

}

Adding the"public" and "payable" keywords make the function publicly accessible and enable it to receive Ether.

4. Execute Access Controls. Access controls are important for ensuring the security of your smart contract. You can use the "modifier" keyword to define access control rules in the contract.

For instance, you might want to limit access to the deposit function to only the contract owner like this:

pragma solidity ^0.8.0;

contract FirstContract {

    uint256 public balance;

    address public owner;

    modifier onlyOwner {

        require(msg.sender == owner, "Only the contract owner can perform this action.");

        _;

    }

function deposit() public payable onlyOwner {

        balance += msg.value;

    }

    function setOwner(address new

Owner) public onlyOwner {

owner = newOwner;

}

}

In this example, the "onlyOwner" modifier is used to restrict access to the deposit and setOwner functions to only the contract owner. The "require" keyword is used to enforce this restriction.

Deploying your Smart Contract

Once you have finished writing the contract, it's time to test and deploy it to the Ethereum network. To do this, we need to use a tool, such as Remix, to compile and deploy the contract. You can also use a local blockchain network, such as Ganache, to test the contract before deploying it live on the main Ethereum network.

You can use the following code to deploy the previous contract:

pragma solidity ^0.8.0;

contract FirstContract {

uint256 public balance;

address public owner;

modifier onlyOwner {

    require(msg.sender == owner, "Only the contract owner can perform this action.");

    _;

}

function deposit() public payable onlyOwner {

    balance += msg.value;

}

function setOwner(address newOwner) public onlyOwner {

    owner = newOwner;

}

constructor() public {

    owner = msg.sender;

}

}

Another option is to open Remix in your browser and paste the code of your smart contract into the editor.

Click on the “Compile” button to compile the code and make sure there are no errors.

Once the code has been compiled, click on the “Run” tab.

Select the environment you want to deploy your contract to, such as a local blockchain network (Ganache) or the Ethereum network. 

Connect to the selected network by entering your wallet address and private key.

Once connected, you will see the deploy button. Click on it to deploy the contract to the Ethereum network.

You should see a transaction hash, which verifies that your contract has been successfully deployed to the Ethereum network.

Interacting with the Contract

To interact with the smart contract, you can use a web3 interface, such as MetaMask, which allows you to send transactions and call functions on the contract from your web browser.

Here is how to start interacting with the smart contract we just created:

1. Install MetaMask on your web browser.

2. Connect MetaMask to the Ethereum network where your contract is deployed.

3. The next thing to do is to obtain the contract's address and ABI (Application Binary Interface). The ABI is a representation of the contract's interface and defines the functions and variables that can be accessed.

4. The next step is to create a web page. On the page, add forms or buttons that allow you to call the contract's functions. You can use a web3 library such as web3.js to interact with the contract from your web page.

5. Initialize web3 and connect to the Ethereum network using this code

const Web3 = require('web3');

const web3 = new Web3(Web3.givenProvider || "http://localhost:8545");

6. Load the contract's ABI and create a contract object:

const abi = [{...}];

const contract = new web3.eth.Contract(abi, contractAddress);

7. Call the contract's functions by calling the appropriate method on the contract object. For instance, to call the deposit function use this code:

contract.methods.deposit().send({value: web3.utils.toWei('1', 'ether')});

This code sends 1 Ether to the deposit function of the contract.

You can also read the contract's state by calling the appropriate 'getter' function. For example, to get the balance use this code:

contract.methods.balance().call().then(function(balance) {

    console.log(balance);

});

This code retrieves the balance from the contract and logs it to the console.

Best Practices for Smart Contract Development

To guarantee the security and reliability of your smart contracts, You must comply with best practices consciously. Here are some key principles to bear in mind:

1. Test carefully before deployment: Use tools like Remix or Truffle to carefully test your smart contract before deploying it to the main Ethereum network. By doing this, any bugs or security holes will be found before they are accessed by the public.

2. Use libraries: When designing smart contracts, reusing code from libraries can help you avoid common security flaws and save time. Use only libraries from reliable sources, and always read the documentation and source code to learn how the libraries operate.

3. Keep your code simple: Simple code is simpler to read and less likely to have security flaws. Keep your code as simple as you can, and stay away from complicated codes.

4. Monitor your contracts: Once your contracts have been deployed to the Ethereum network, keep an eye on them for any unusual activity. To keep track of the transactions and events that your contracts generate, you can use a tool like Etherscan.

5. Create code that is clear and easy to read. Make sure your code is well-structured, commented on, and understandable to other developers. The contract will be simpler to maintain and audit as a result.

6. The objective of the contract should be kept straightforward: Ensure that your contract only has the bare minimum number of functions and lines of code necessary to fulfill its intended purpose. By doing this, the attack surface is decreased and the contract is simpler to understand and verify.
7. Check the contract code: Ask a third-party security expert to evaluate the contract code to find any potential security holes.
8. Maintain the contract's upgradeability: Consider the potential that you could later need to upgrade your contract. To make changes or address bugs without deploying a new contract, design your contract to be upgradeable if necessary.

Conclusion

In this brief smart contract development course, we looked at the fundamentals of developing smart contracts and guided you through the creation, deployment, and interaction with your first smart contract. Although this is only the tip of the iceberg, it gives you a strong foundation to build on as you continue your adventure in the exciting world of smart contract development. Don't forget to follow some of the best practices we have outlined. It will help you reduce the risk of security vulnerabilities and guarantee the reliability and safety of your solidity smart contracts.