Run the following commands to install:

• Web3.py:  $ Pip Install web3
• Solcx:       $ pip install py-solc-x
• Eth_Utils:  $ pip install eth-utils==1.1.2
• Dotenv:     $ pip install python-dotenv

Note: When installing you might find issues related to library version. If you observe, try with below to resolve:

$ pip install web3==4.1.9

$ pip install eth-utils==1.10.0

Details of the Platform for performing blockchain operations:

No need to worry if you do not have prior experience or knowledge on Solidity, I have an article on this and it a “16 Step Guide to Setup and program a Ledger Smartcontract using Solidity” will help you understand step by step, till then you can use the sample file “SimpleStorage.sol” – Download

We will be using “Gananche” tool to perform blockchain operations locally before deploying. This tool is used to test blockchain transactions, inspect changes etc.. (Tool has both CLI and GUI)

7 Steps to Setup and program Smartcontract:

STEP – 1: Importing Libraries

from eth_utils import address

from web3 import Web3

import os

from solc import compile_standard, install_solc

from dotenv import load_dotenv

import json

STEP – 2: Reading the .SOL file using python

with open("./SimpleStorage.sol", "r") as file:

    simple_storage_file = file.read()

STEP – 3: Compiling the Smartcontract

For this Step we use “py_solc_x” library to use standard compile function. This is used to break the code into Assembly Language, which is much closer to Machine Language for execution.

Before going into code, we need to understand 4 parameters used to compile Smartcontracts:

lauguage: Solidaty language to understand the details of the Smartcontract

sources: Smartcontract file, content and variables used to store information of Smartcontract

outputSelection: To get information related to ABI, Metadata, Bytecode and its sourcemap.

solc_version: This is the version used in the Smartcontract code

Once we understand the above information, Open the file and save it into JSON formatted file:

compiled_sol = compile_standard(

    {

        "language": "Solidity",

        "sources": {"SimpleStorage.sol": {"content": simple_storage_file}},

        "settings": {

            "outputSelection": {

                "*": {

                    "*": ["abi", "metadata", "evm.bytecode", "evm.bytecode.sourceMap"]

                }

            }

        },

    },

    solc_version="0.6.0",

)

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

    json.dump(compiled_sol, file)

STEP – 4: Extraction (ABI & Bytecode from Solidity Smartcontract)

Bytecode contains the information for code execution. It includes the key commands in assembly language that are executed at low-level or machine-level instead of the whole smart contract. In other words, this is the code that is executed by Ethereum Virtual Machine (EVM) and which governs the working of the smart contract file.

Below code is in JSON format, this is from the compiled contract file

# get bytecode

bytecode = compiled_sol["contracts"]["SimpleStorage.sol"]["SimpleStorage"]["evm"][

    "bytecode"

]["object"]

Besides, ABI is “Application Binary Interface” this is also an important piece of information for a Smartcontract.

ABI in Smartcontract is responsible for interaction between methods and structures, it is similar to Application Programming Interface (API). In the above compiled JSON object if you print the data, you will find ABI with Smartcontract file inputs, names, rdata types and outputs etc..

# get abi

abi = json.loads(

    compiled_sol["contracts"]["SimpleStorage.sol"]["SimpleStorage"]["metadata"]

)["output"]["abi"]

STEP – 5: Local Ethereum Blockchain connection using Ganache

Install Ganache tool, use Quick Start and get the information from the tool.

w3 = Web3(

    Web3.HTTPProvider("HTTP://127.0.0.1:7545")

)

chain_id = 1337

my_address = "0x23959D4e00640f2D152dA3F96474504e63Aa6d2D"

# private_key = os.getenv("PRIVATE_KEY")

private_key = "0x4d08735ff981fa51e9c56c79c99d121c9f66754c27926ca5014fdaa2d71e904f"

Few things to consider here:

• Add a 0x before pasting the private key from Ganache.
• It is good practice not to leave your private key in the code. Instead, create a new file–.env. In this file, write “PRIVATE_KEY=0x,” and after 0x, paste in the private key.
• To find out the Chain IDs of different blockchains, head here.

STEP – 6: Performing Smartcontract Transaction using Python 

This is the part where you need to keeps your eyes wide open and do not get disturbed. 

initialize the smart contract in Python by setting parameters for ABI and Bytecode

# initialize contract

SimpleStorage = w3.eth.contract(abi=abi, bytecode=bytecode)

Next it is important to know about Nonce - it’s an arbitrary number that can be used once in blockchain communication. Nonce tracks the number of transactions with help of function – “getTransactionCount” on the addressed used.

nonce = w3.eth.getTransactionCount(my_address)

Few things to consider here:

After creating Smartcontract in Python, there are 3 more things to do –