Create README.md

README.md

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+# Send Transaction using web3
+
+Write a contract, build and deploy it using truffle on Rinkeby testnet. Write a JavaScript code to sign and send a transaction to the deployed contract. Write a JavaScript code to get the transaction (calling a getter function).
+
+
+## Roadmap
+
+- Setting up Environment for Truffle
+
+- Installing necessary tools
+
+- Writing Smart Contract
+- Compiling and deploying Smart Contract on Public Blockchain (Rinkeby)
+- Writing a JavaScript code to sign and send transaction
+- Writing a JavaScript code to get transaction (calling a getter function)
+- Testing scripts
+
+
+## Setting up Environement for truffle
+### Prerequisite for truffle
+
+Node.js => 14.0.0-17.0.0
+
+Git => 2.10.0
+
+NPM => 6.14.15-9.0.0
+
+Truffle suit => 5.0.0-6.0.0
+
+Ganache => 6.0.0-8.0.0
+
+Install  truffle with npm
+
+```bash
+  npm install -g truffle
+```
+
+Install web3
+
+```bash
+  npm install web3
+```
+
+Install dotenv
+
+```bash
+  npm install dotenv
+```
+
+Install truffle hdwallet provider
+
+```bash
+npm install @truffle/hdwallet-provider
+```
+
+## Getting started
+
+Run the following commands
+
+```bash
+npm init -y
+npx truffle init
+```
+
+#### Now replace ```Migrations.sol``` contract with your custom contract in the contracts folder
+
+```bash
+//SPDX-License-Identifier:GPL-3.0
+
+pragma solidity >= 0.7.0 <0.9.0;
+
+contract SendTx
+{
+    uint public number;
+
+    /**
+    * @dev set function is used to set the value of number.
+    * @param _num - Will be assigned to variable number.
+    */
+    function set(uint _num) public{
+        number = _num;
+    }
+
+    /**
+     * @dev get function is used to get the value of number.
+     */
+    function get() public view returns(uint)
+    {
+        return number;
+    }
+}
+```
+Now replace the ```1_Migrations.js``` file with the following file
+
+```bash
+const SendTx = artifacts.require("SendTx");
+
+module.exports = function (deployer) {
+  deployer.deploy(SendTx);
+};
+```
+
+Now configure the ```truffle-config.js``` file like this...
+where mnemonic is the security phrase of your wallet like MetaMask
+
+```bash
+const HDWalletProvider = require('@truffle/hdwallet-provider');
+const mnemonic = 'Enter your mnemonic here';
+
+module.exports = {
+    networks: {
+    rinkeby: {
+        provider: () => new HDWalletProvider(mnemonic, `Enter your infura API`),
+        network_id: 4,
+        gas: 5500000,
+        confirmations: 2,
+        timeoutBlocks: 200,
+        skipDryRun: true
+    },
+    },
+   mocha: {
+   },
+   compilers: {
+     solc: {
+       version: "0.8.15",
+     }
+   },
+ };
+```
+
+## Time to compile and deploy the contract on Rinkeby testnet
+
+```bash
+npx truffle migrate --network rinkeby
+```
+
+### You will get a contract address, copy and paste that address in the ```process.env``` file (that we will create next)
+
+now create a file with name ```process.env``` and paste the following code in it
+
+```bash
+API_URL = "Paste your infura API URL here"
+PRIVATE_KEY = "Paste your private key here"
+CONTRACT_ADDRESS = "Paste your "
+ACCOUNT_ADDRESS = "0x049fd9EbD3e514D28745Eac8c9D6B67655479d2b"
+```
+
+## Writing JavaScript files
+
+Create two JavaScript files i test folder named ```sendTx.js``` and ```getTx.js``` for sending and getting transaction and paste the following codes in them...
+
+```sendTx.js```
+
+```bash
+const Web3 = require("web3");
+require("dotenv").config({path: __dirname + "/./../process.env"});
+const abiFile = require("../build/contracts/SendTx.json");
+
+const web3 = new Web3(process.env.API_URL);
+
+const pvtKey = process.env.PRIVATE_KEY;
+const contractAddress = process.env.CONTRACT_ADDRESS;
+const accountAddress = process.env.ACCOUNT_ADDRESS;
+
+const contract = new web3.eth.Contract(abiFile.abi, contractAddress);
+
+const sendTransaction = async() =>
+{
+    const _from = accountAddress;
+
+    const tx = {
+        from: _from,
+        to: contractAddress,
+        gas: 300000,
+        data: contract.methods.set(2017).encodeABI()
+    }
+
+    const signed = await web3.eth.accounts.signTransaction(tx, pvtKey);
+
+    web3.eth.sendSignedTransaction(signed.rawTransaction).on(
+        "receipt", (receipt)=>{
+            console.log(receipt);
+        }
+    )
+}
+console.log("Sending Transaction and saving value of number as 2017 ...");
+sendTransaction();
+```
+
+``` getTx.js```
+
+```bash
+const Web3 = require('web3');
+require("dotenv").config({path: __dirname + "/./../process.env"});
+const abiFile = require("../build/contracts/SendTx.json");
+
+const getTransaction = async()=>
+{
+    const web3 = new Web3(process.env.API_URL);
+    const CONTRACT_ADDRESS = process.env.CONTRACT_ADDRESS;
+    const CONTRACT_ABI =  abiFile.abi;
+
+    const sendTxContract = new web3.eth.Contract(CONTRACT_ABI,CONTRACT_ADDRESS);
+    const getTx = await sendTxContract.methods.get().call()
+    console.log("Calling get Function and getting the value of number which is :", getTx);
+    console.log("Transaction sucessfull ...");
+}
+getTransaction();
+```
+
+Save these files
+
+# Testing
+
+Now it's time to test our scripts by interacting with contract that we have deployed on Rinkeby testnet
+
+Run the following command
+
+```bash
+node test/sendTx.js
+```
+
+You should get response like this...
+
+![send](https://user-images.githubusercontent.com/96762657/182704637-5a44e0e0-9bdf-4566-baa1-dada3dd5080a.PNG)
+
+Now run the ```getTx.js``` file by following command
+
+```bash
+node test/getTx.js
+```
+
+You should get result like this...
+
+![get](https://user-images.githubusercontent.com/96762657/182705306-2bd6ec22-9a22-4693-bb75-6afb9c7de404.PNG)
+
+
+## It's Done