Assignment : Integration with frontend

1. Download the frontend from this link https://drive.google.com/file/d/1UuALet56_czOseatkx2-jCsgUwWiYFAO/view?usp=sharingthen run npm i when you run it should look like this

then npm i axios

2.  Then go to your backend run npm i cors then add the code below to your index.js 

const express = require("express");
const app = express();
//add this line 👇
const cors = require("cors");
const usersRouter = require("./routers/users");
const transactionsRouter = require("./routers/transactions");

const port = 5000;
app.use(express.json());
//add this line 👇
app.use(cors({ origin: ["http://localhost:5173"], credentials: true }));

app.use("/users", usersRouter);
app.use("/transactions", transactionsRouter);

app.listen(port, () => {
	console.log(`Example app listening on port ${port}`);
});

3. Then go to frontend->src->pages->Homepage.jsx add this codethese

import axios from "axios";

//edit the getBalance 👇
const getBalance = async (userId) => {
		const balance = await axios.get(
			`http://localhost:5000/transactions/balance?userId=${userId}`
		);
		setUserData({ balance: balance.data.data.balance });
	};
useEffect(() => {
		getBalance(1);
	}, []);

4. When restart the balance on your web should be base on your database

5. Go to your backend in the directory controllers->transactions create deposit.js

6. write down this code

const connection = require("../../services/database");

const deposit = async (req, res) => {
	const { userId, amount, note } = req.body;
	// Check if userId and amount is number or not
	const checkUserId = new RegExp(/^\d+$/).test(userId);
	const checkAmount = new RegExp(/^\d+$/).test(amount);
	// Return error if the userId and amount are null or it's not a number
	if (!userId || !checkUserId || !amount || !checkAmount) {
		return res.json({
			success: false,
			data: null,
			error: "Invalid input",
		});
	}
	try {
		// Get user data
		const userDataQuery = await connection
			.promise()
			.query(`SELECT firstname FROM users WHERE id = ${userId}`);
		const firstname = userDataQuery[0][0].firstname;
		if (!firstname) {
			return res.status(404).json({
				success: false,
				data: null,
				error: "User not found",
			});
		}
		// Insert the transaction log to the database
		await connection
			.promise()
			.query(
				`INSERT INTO banks (owner, sender, amount, type, bank, note) VALUES ('${userId}', '${firstname}', '${amount}', 'deposit', 'SCB', '${note}')`
			);
		// Update the balance
		await connection
			.promise()
			.query(
				`UPDATE users SET balance = balance + ${amount} WHERE id = ${userId}`
			);
		// Return success if balance is upadated
		return res.json({
			success: true,
			data: null,
			error: null,
		});
	} catch (error) {
		console.error("Error:", error);
		return res.status(500).json({
			success: false,
			data: null,
			error: error.message,
		});
	}
};
module.exports = deposit;

7. Add this to transaction.js in directory routers

const express = require("express");
const getBalance = require("../controllers/transactions/getBalance");
const updateBalance = require("../controllers/transactions/updateBalance");
//add this line 👇
const deposit = require("../controllers/transactions/deposit");
const transactionsRouter = express.Router();

transactionsRouter.get("/balance", getBalance);
transactionsRouter.patch("/update", updateBalance);
//add this line 👇
transactionsRouter.post("/deposit", deposit);
module.exports = transactionsRouter;

8. Go to your Homepage.jsx and update the handleDeposit function

const handleDeposit = async (amount, note) => {
		await axios.post(`http://localhost:5000/transactions/deposit`, {
			userId: 1,
			amount: amount,
			note: note,
		});
  		// call the function to update the balance after we make a deposit
		getBalance(1);
	};

9. Now it's your turn try to make the /withdraw and /all endpoint in transactions controllers work in the backend and then integrate with frontend

Hints

 Withdraw

• When writing the endpoint don't forget to make sure that if the balance is more than the amount that you are going to withdraw
• The balance need to be deduct with the amount

getAllTransactions

• Hints uncomment this in directory components->HomePage->TransactionCard.jsx when doing the /transactions/all
• Assign the value to the useState of transactions,setTransactions

-END-