How to build an Post Office Info App Using Pin Codes – India API?

So today, I am building a post office info app that will take the area pin code from the user and list all the post offices in the area. So without any further ado, let’s jump in!

Stack

We need to choose a stack first to build this application. I have decided to go with the Jamstack.

I am going to use Next.js for the frontend and TailwindCSS for the styling.

If you don’t know about Next.js, it is a JavaScript framework built on top of React and provides features like server-side rendering, static site generation, etc. Tailwind is a CSS framework that provides utility classes to speed up the development process.

Choosing The API

Let’s find an API that we can use to search for post offices. Go to RapidAPI Hub and create an account if you haven’t already and then search for “post offices api” in the search section.

You will see different search results related to food APIs. For this piece, I am using Pin Codes – India API.

It is a free API, so you do not need to subscribe to it. However, you will need your RapidAPI key. Go ahead and save the x-rapidapi-key so you can use it later.

Building The UI

You can create a Next.js boilerplate with TailwindCSS integrated by running the following command in your terminal. So let’s do that.

sh
Copy
npx create-next-app -e with-tailwindcss post-office-info-app

This command is going to take a minute to set everything up. After generating the boilerplate, you will see a folder with the name post-office-info-app has been created. Open this folder in your preferred code editor. I will use VSCode for this project.

Project Files

When you open the project in your code editor, you will see the following directories and files in the root directory:

• pages directory: Inside it, you will have files index.js, _app.js, and another directory called api. You only need to know about the index.js file that is the main entry point in your project.
• public directory: This directory contains icons. You place your static files here to load later in the application.
• node_modules: It’s another directory that contains all the node modules you are using in your application.
• package.json: This file contains the metadata of your project.
• package-lock.json: This file is responsible for tracking the exact version of every installed package.
• postcss.config.js: This file contains PostCSS configurations.
• tailwind.config.js: It contains TailwindCSS configurations.
• readme.md: It’s a markdown file for documentation.

Before we move on to writing the code, open this file, and copy all of its content, then paste it inside the tailwind.config.js file in your project. These are some TailwindCSS configurations I have done specifically for this project. I have added some colors that you do not have by default with TailwindCSS and set some screen sizes.

Now let’s start writing the code. I am going to do it in steps so you can follow along.

→ STEP #1

Open the pages/index.js file and remove all the existing code. After this, copy-paste the following code there:

jsx
Copy
export default function Home() {
	return (
		<div className="flex flex-col items-center">
			<h2 className="font-raleway font-bold text-6xl text-primary pt-20 pb-6 md:text-3xl">
				Post <span className="text-danger">Office</span> Finder App
			</h2>
			<h3 className="text-danger text-2xl font-raleway font-bold uppercase tracking-wide mb-14 md:text-base md:px-4 md:text-center">
				Get India Post Office Details using the pin code
			</h3>
		</div>
	);
}

It will create two headings for you with the text “Post Office Finder App” and “Get India Post Office Details using the pin code”. You can change it to anything you prefer.

→ STEP #2

Now let’s create an input field and a search button. The user will be able to type the pin code in the input box and use the search button to get the post office details.

For this, copy the following code and paste it in pages/index.js:

jsx
Copy
export default function Home() {
	return (
		<div className="flex flex-col items-center">
			<h2 className="font-raleway font-bold text-6xl text-primary pt-20 pb-6 md:text-3xl">
				Post <span className="text-danger">Office</span> Finder App
			</h2>
			<h3 className="text-danger text-2xl font-raleway font-bold uppercase tracking-wide mb-14 md:text-base md:px-4 md:text-center">
				Get India Post Office Details using the pin code
			</h3>
			<div className="flex flex-col justify-between items-center w-full md:items-center">
				<form className="flex w-full justify-center md:flex-col md:w-5/6 ">
					<input
						autoFocus={true}
						type="number"
						className="border-none outline-none w-2/5 bg-primary px-4 py-2 rounded-sm font-raleway md:w-full"
						placeholder="Pin code..."
					/>
					<button className="outline-none border border-danger text-secondary font-bold font-raleway ml-4 w-52 px-12 py-2 rounded-sm bg-danger text-primary transition duration-300 hover:bg-bc hover:text-primary md:ml-0 md:mt-4">
						Search
					</button>
				</form>
			</div>
		</div>
	);
}

This code is going to create an input field and button. I have also styled them a little bit using TailwindCSS.

→ STEP #3

Let’s create some states to store the pin code and the post office details that we will receive from the API. For this, copy-paste the following code in pages/index.js:

jsx
Copy
import {useState} from 'react';
export default function Home() {
	const [pinCode, setPinCode] = useState();
	const [info, setInfo] = useState(null);
	return (
		<div className="flex flex-col items-center">
			<h2 className="font-raleway font-bold text-6xl text-primary pt-20 pb-6 md:text-3xl">
				Post <span className="text-danger">Office</span> Finder App
			</h2>
			<h3 className="text-danger text-2xl font-raleway font-bold uppercase tracking-wide mb-14 md:text-base md:px-4 md:text-center">
				Get India Post Office Details using the pin code
			</h3>
			<div className="flex flex-col justify-between items-center w-full md:items-center">
				<form className="flex w-full justify-center md:flex-col md:w-5/6 ">
					<input
						autoFocus={true}
						type="number"
						className="border-none outline-none w-2/5 bg-primary px-4 py-2 rounded-sm font-raleway md:w-full"
						placeholder="Pin code..."
						onChange={e => setPinCode(e.target.value)}
					/>
					<button className="outline-none border border-danger text-secondary font-bold font-raleway ml-4 w-52 px-12 py-2 rounded-sm bg-danger text-primary transition duration-300 hover:bg-bc hover:text-primary md:ml-0 md:mt-4">
						Search
					</button>
				</form>
			</div>
		</div>
	);
}

You can see that I have added an onChange event handler to set the state value as soon as the user types something in the input box.

→ STEP #4

Let’s integrate the API now. For this, first, create a .env.local file and paste the following in it:

sh
Copy
NEXT_PUBLIC_RAPIDAPI_KEY=YOUR-RAPIDAPI-KEY

You need to replace YOUR-RAPIDAPI-KEY here with the API key you got when you subscribed to the Pin Codes – India API. It is the value of x-rapidapi-key that you saved earlier.

Now download and add axios in your project. For this, run the following command in the terminal:

sh
Copy
npm install axios

Now import axios at the top of the pages/index.js.

js
Copy
import axios from 'axios';

→ STEP #5

RapidAPI Hub provides you with code snippets in different languages for integrating the API. I am going to use the (JavaScript) Axios one.

Fetching data using (JavaScript) Axios

Now create a file with the name info.js inside the pages/api directory. It is going to create a REST API endpoint for you. The endpoint point will look like this:

sh
Copy
http://localhost:3000/api/info

Now copy the following code in this file:

js
Copy
import axios from 'axios';
export default function handler(req, res) {
	if (req.method === 'GET') {
		const options = {
			method: 'POST',
			url: 'https://pincode.p.rapidapi.com/',
			headers: {
				'content-type': 'application/json',
				'x-rapidapi-host': 'pincode.p.rapidapi.com',
				'x-rapidapi-key': process.env.NEXT_PUBLIC_RAPIDAPI_KEY
			},
			data: {searchBy: 'pincode', value: req.query.pinCode}
		};
		axios
			.request(options)
			.then(function (response) {
				res.status(200).json(response.data);
			})
			.catch(function (error) {
				console.error(error);
			});
	} else {
		res.status(400);
	}
}

This code makes an API call to the Pin Codes – India API on the server and returns the results to the user. It executes when the user makes an API call to the info endpoint I mentioned above.

Once you are done, copy the following code in the pages/index.js file:

jsx
Copy
import {useState} from 'react';
import axios from 'axios';
export default function Home() {
	const [pinCode, setPinCode] = useState();
	const [info, setInfo] = useState(null);
	const [btnText, setBtnText] = useState('Search');
	/**
	 *
	 *
	 * @param
	 */
	const getPostOfficeInfo = async e => {
		e.preventDefault();
		try {
			setBtnText('Loading...');
			const res = await axios.get(`/api/info`, {
				params: {
					pinCode
				}
			});
			setInfo(res.data);
		} catch (err) {
			console.log(err);
		}
		setBtnText('Search');
	};
	return (
		<div className="flex flex-col items-center">
			<h2 className="font-raleway font-bold text-6xl text-primary pt-20 pb-6 md:text-3xl">
				Post <span className="text-danger">Office</span> Finder App
			</h2>
			<h3 className="text-danger text-2xl font-raleway font-bold uppercase tracking-wide mb-14 md:text-base md:px-4 md:text-center">
				Get India Post Office Details using the pin code
			</h3>
			<div className="flex flex-col justify-between items-center w-full md:items-center">
				<form className="flex w-full justify-center md:flex-col md:w-5/6 ">
					<input
						autoFocus={true}
						type="number"
						className="border-none outline-none w-2/5 bg-primary px-4 py-2 rounded-sm font-raleway md:w-full"
						placeholder="Pin code..."
						onChange={e => setPinCode(e.target.value)}
					/>
					<button
						className="outline-none border border-danger text-secondary font-bold font-raleway ml-4 w-52 px-12 py-2 rounded-sm bg-danger text-primary transition duration-300 hover:bg-bc hover:text-primary md:ml-0 md:mt-4"
						onClick={getPostOfficeInfo}
					>
						{btnText}
					</button>
				</form>
				{info && (
					<div className="flex flex-col text-primary text-sm text-raleway mt-12 w-3/6 h-4/5  md:flex-col md:w-4/6 md:h-full md:mb-12">
						{info.map(postOffice => {
							return (
								<div key={info.indexOf(postOffice)}>
									<h3 className="font-raleway font-semibold text-danger text-2xl text-primary pb-6 md:text-xl">
										{postOffice.office}
									</h3>
									<table className="bg-white w-full text-primary mb-8 md:text-sm md:mx-2">
										<tbody className="text-primary font-normal">
											<tr>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													Circle
												</th>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													{postOffice.circle}
												</th>
											</tr>
											<tr>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													Delivery
												</th>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													{postOffice.delivery}
												</th>
											</tr>
											<tr>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													District
												</th>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													{postOffice.district}
												</th>
											</tr>
											<tr>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													Division
												</th>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													{postOffice.division}
												</th>
											</tr>
											<tr>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													Phone
												</th>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													{postOffice.phone}
												</th>
											</tr>
											<tr>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													Region
												</th>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													{postOffice.region}
												</th>
											</tr>
											<tr>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													Related Head Office
												</th>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													{
														postOffice.related_headoffice
													}
												</th>
											</tr>
											<tr>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													Taluk
												</th>
												<th className="border border-primary text-left px-4 py-4 font-normal">
													{postOffice.taluk}
												</th>
											</tr>
										</tbody>
									</table>
								</div>
							);
						})}
					</div>
				)}
			</div>
			<div className="flex flex-col mt-10 justify-end h-36 md:h-24">
				<p className="block mb-10 text-center text-primary text-xs">
					Made by RapidAPI DevRel Team -{' '}
					<a
						className="hover:text-danger"
						href="https://github.com/RapidAPI/DevRel-Examples-External"
					>
						See more examples like this
					</a>
				</p>
			</div>
		</div>
	);
}

You can see that I have created a function, getPostOfficeInfo, to request the API. I have also created a UI that is conditionally rendering on the screen based on the info state variable’ value.

Wrap Up

That’s it. We have successfully built an Post Office Finder App using Pin Codes – India API. You can find the source code of this web app here.

In the end, it will look something like this:

Post Office Finder App built with Next.js and Pin Codes – India API