1. Local contracts with Python and Ganache

This scripts compiles a contract and gets the bytecode and abi

bytecode is the compiled machine code that will be deployed to the Ethereum blockchain.
abi is the Application Binary Interface, which defines the functions and events in the smart contract, allowing interaction with it after deployment.

from solcx import compile_standard, install_solc
import json

with open("./SimpleWallet.sol", "r") as file:
    simple_storage_file = file.read()

# Compile
install_solc("0.8.0")
compiled_sol = compile_standard(
    {
        "language": "Solidity",
        "sources": {"SimpleWallet.sol": {"content": simple_storage_file}},
        "settings": {
            "outputSelection": {
                "*": {
                    "*": ["abi", "metadata", "evm.bytecode", "evm.bytecode.sourceMap"]
                }
            }
        },
    },
    solc_version="0.8.0",
)

with open("compiled_code.json", "w") as file:
    json.dump(compiled_sol, file)

# bytecode
# ABI
bytecode = compiled_sol["contracts"]["SimpleWallet.sol"]["SimpleWallet"]["evm"][
    "bytecode"
]["object"]
abi = json.loads(
    compiled_sol["contracts"]["SimpleWallet.sol"]["SimpleWallet"]["metadata"]
)["output"]["abi"]

This reads the content of the Solidity file SimpleWallet.sol into the variable simple_storage_file.
The compile_standard function compiles the solidity code and output is stored in the compiled_sol variable.
The bytecode and ABI are extracted from the compiled Solidity code

Deploying into local Ganache EVM

Ganache is a personal blockchain for rapid Ethereum and Filecoin distributed application development. You can use Ganache across the entire development cycle; enabling you to develop, deploy, and test your dApps in a safe and deterministic environment.

Ganache UI

Pasted image 20240621154320.png

Here we can get an address and a private key to deploy a contract with

w3 = Web3(Web3.HTTPProvider("http://127.0.0.1:7545"))

# Debug: Check connection and network ID
if w3.is_connected():
    print("Connected to Web3")
    print(f"Network ID: {w3.eth.chain_id}")
else:
    print("Failed to connect to Web3")

chain_id = 1337
my_address = "0xc7677e5e27D02AA7ea6Bd721d51D570058552154"
private_key = os.getenv("PRIVATE_KEY")

# Create the contract in Python
SimpleStorage = w3.eth.contract(abi=abi, bytecode=bytecode)
# Get the latest transaction
nonce = w3.eth.get_transaction_count(my_address)
# Submit the transaction that deploys the contract
transaction = SimpleStorage.constructor().build_transaction(
    {
        "chainId": chain_id,
        "gasPrice": w3.eth.gas_price,
        "from": my_address,
        "nonce": nonce,
    }
)
# Sign the transaction
signed_txn = w3.eth.account.sign_transaction(transaction, private_key=private_key)
print("Deploying Contract!")
# Send it!
tx_hash = w3.eth.send_raw_transaction(signed_txn.rawTransaction)
# Wait for the transaction to be mined, and get the transaction receipt
print("Waiting for transaction to finish...")
tx_receipt = w3.eth.wait_for_transaction_receipt(tx_hash)
print(f"Done! Contract deployed to {tx_receipt.contractAddress}")

chain_id: The chain ID of the Ganache network you are working with.
my_address: The Ethereum address from which transactions will be sent.
private_key: The private key associated with my_address, retrieved from environment variables for security.

Interacting with the contract

Here we call the getBalance function from the Simple Wallet contract we deployed
If we just deploy the contract we should get 0
Then we send wei to the contract, we can do this by calling the function deposit and sending wei
Then we call getBalance again and we should see that now the contract returns 1 eth

simple_wallet = w3.eth.contract(address=tx_receipt.contractAddress, abi=abi)

print(simple_wallet.functions.getBalance().call())

tx = simple_wallet.functions.deposit().build_transaction(
    {
        "chainId": chain_id,
        "gasPrice": w3.eth.gas_price,
        "from": my_address,
        "nonce": nonce + 1,
        "value": w3.to_wei(1, "ether"),  # Sending 1 ETH
    }
)
signed_tx = w3.eth.account.sign_transaction(tx, private_key=private_key)
hash = w3.eth.send_raw_transaction(signed_tx.rawTransaction)
recipt = w3.eth.wait_for_transaction_receipt(hash)

print(simple_wallet.functions.getBalance().call())

Using ganache CLI instead of UI

Install ganache cli using npm

npm install -g ganache

You can use the deterministic parameter to always use the same addresses and private keys

ganache --deterministic

ganache v7.9.2 (@ganache/cli: 0.10.2, @ganache/core: 0.10.2)
Starting RPC server

Available Accounts
==================
(0) 0x90F8bf6A479f320ead074411a4B0e7944Ea8c9C1 (1000 ETH)