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Updated on 2025-03-02

Summary of the application and practice of Python in blockchain smart contract development

Python's application and practice in blockchain smart contract development

1. 🚀 Basic concepts of smart contracts

What are smart contracts and their role in blockchain

Smart contracts are automatically executed and tampered with code snippets that exist on the blockchain. They are automatically triggered by specific conditions, simplifying complex contract execution processes. The key feature of smart contracts is decentralization, which makes it impossible for anyone to change once the contract is deployed. Smart contracts can be applied to multiple fields such as finance, law, and supply chain management. By reducing the participation of intermediary institutions, they reduce costs and improve efficiency.

Smart contract writing, deployment and execution process

Smart contracts are usually written in the Solidity language. First, developers need to define the structure, functions and variables of the contract. Here is a simple example of a Solidity contract:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract SimpleStorage {
    uint256 storedData;
    function set(uint256 x) public {
        storedData = x;
    }
    function get() public view returns (uint256) {
        return storedData;
    }
}

This contract allows the user to store and retrieve a number. After writing, compile and deploy it to the Ethereum network using a tool like the Remix IDE. After deployment, users can interact with the contract through or through the function of setting up and obtaining data.

2. 🔧 Python Smart Contract Framework

Write and deploy smart contracts using Brownie and

Brownie is a powerful Python framework for writing and deploying smart contracts. First install Brownie:

pip install eth-brownie

Initialize the Brownie project in the project directory:

brownie init

Next, you can create a contract file. Then, create a Python script in Brownie for deployment:

from brownie import SimpleStorage, accounts
def deploy_contract():
    account = accounts[0]
    simple_storage = ({"from": account})
    return simple_storage

Run this script from the command line to deploy the contract. Brownie provides simplified processes and commands that allow developers to easily deploy and interact with contracts.

Write smart contracts using Solidity and call and test them through Python

After the contract is deployed, you can use the library to call the contract's methods. First, install:

pip install web3

Then, you can write the following Python code to interact with the contract:

from web3 import Web3
# Connect to the Ethereum nodew3 = Web3(('http://127.0.0.1:8545'))
# Contract address and ABIcontract_address = 'Your contract address'
contract_abi = 'Contracted ABI'
simple_storage = (address=contract_address, abi=contract_abi)
# Set valuetx_hash = simple_storage.(10).transact({'from': [0]})
(tx_hash)
# Get the valuestored_data = simple_storage.().call()
print(stored_data)  # Output: 10

The above code shows how to use setting and obtaining data in smart contracts to achieve a comprehensive interaction with the contract.

3. 🌐 Django integrates with blockchain

Integrate in Django to achieve interaction with blockchains such as Ethereum

Django is a popular Python web framework that integrates seamlessly with blockchain. In a Django project, you can create a view that can be used to interact with smart contracts. First, make sure to install it in your Django project.

Create a Django view:

from  import JsonResponse
from web3 import Web3
def get_stored_data(request):
    w3 = Web3(('http://127.0.0.1:8545'))
    contract_address = 'Your contract address'
    contract_abi = 'Contracted ABI'
    simple_storage = (address=contract_address, abi=contract_abi)
    stored_data = simple_storage.().call()
    return JsonResponse({'stored_data': stored_data})

When the user accesses this view, the data stored in the contract will be returned, realizing basic interaction with Ethereum.

Use Python Web applications to handle cryptocurrency payments, smart contract calls and other functions

When processing cryptocurrency payments through Django, you can create a simple payment view. This view can accept user payment requests and call related functions of the smart contract. Here is the sample code:

def make_payment(request):
    if  == 'POST':
        amount = ['amount']
        tx_hash = simple_storage.(amount).transact({'from': [0]})
        (tx_hash)
        return JsonResponse({'status': 'Payment successful', 'tx_hash': tx_hash.hex()})

This code implements the basic function of users to make cryptocurrency payments in web applications, and realizes data storage and status updates by calling smart contracts.

4. 🛠️ Decentralized Application (DApp) Development

Build API for decentralized applications in Flask/FastAPI

Flask and FastAPI are lightweight Python web frameworks suitable for building backend APIs for DApps. In these frameworks, interaction with blockchain can be used. Here is an example of creating an API using FastAPI:

from fastapi import FastAPI
from web3 import Web3
app = FastAPI()
w3 = Web3(('http://127.0.0.1:8545'))
contract_address = 'Your contract address'
contract_abi = 'Contracted ABI'
simple_storage = (address=contract_address, abi=contract_abi)
@("/get-data")
def read_data():
    stored_data = simple_storage.().call()
    return {"stored_data": stored_data}

This API allows users to obtain data from smart contracts through HTTP requests, showing how to implement back-end logic in DApps.

Integrate blockchain wallet and authentication mechanism in Python web applications

Integrating blockchain wallets is an important step in DApp development. Existing wallet solutions, such as MetaMask, can be used to handle user authentication. By interacting with MetaMask on the front end, users can securely connect to their Ethereum wallet. Here is a simplified process:

  • Connect to MetaMask using JavaScript on the front end.
  • In the Flask/FastAPI backend, verify the user's request.
  • Process user operations through smart contract calls.
async function connectWallet() {
    if () {
        const accounts = await ({ method: 'eth_requestAccounts' });
        ('Connected account:', accounts[0]);
    }
}

This code snippet enables users to connect to their Ethereum wallet, ensuring the security of transactions and the validity of authentication.

5. 🔒 Security and Audit

Common types of smart contract security vulnerabilities and their protection

The security of smart contracts is crucial, and common security vulnerabilities include reentry attacks, integer overflows, and insufficient access control. To protect smart contracts, the following protective measures can be taken:

  • Use the contract library: For example, the secure contract library provided by OpenZeppelin uses standardized code to reduce vulnerability risks.
  • Testing and auditing: Perform adequate unit testing and auditing before deploying the contract to ensure the correctness and security of the logic. How to perform security audit of smart contracts through Python tools

Use Python tools for smart contract audits, which can leverage tools such as Slither and Mythril. Here is an example of contract analysis using Slither:

slither your_contract.sol

Slither will analyze contracts and return potential security issues to help developers fix vulnerabilities in a timely manner. This static analysis tool provides strong support for the security audit of smart contracts.

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