My First Backend Application: Palindrome Checker

In this project, I ventured into the world of backend development to create a simple Node.js application that checks if a given string is a palindrome. A palindrome is a word, phrase, or sequence of characters that reads the same forward as backward (ignoring spaces, punctuation, and capitalization).

Learning Journey

Node.js and HTTP Server: I learned how to set up a basic HTTP server using Node.js and handle different HTTP requests.
Server-Side Logic: Implementing the palindrome logic on the server side was a key learning point. This approach ensures that the logic is secure and cannot be tampered with by the end-users.
Parsing URL and Query Strings: I got hands-on experience with parsing URLs and query strings to extract parameters from the HTTP requests.
Sending JSON Responses: I learned how to send JSON responses back to the client and handle different HTTP status codes.
Handling Static Files: I figured out how to serve static files like HTML, CSS, and JavaScript from the server.

Project Structure

The main components of the project include:

server.js: This is the heart of the application where the server is set up, and different HTTP requests are handled.
index.html: The main HTML file that provides a user interface for inputting strings and displaying results.
css/style.css: A simple CSS file to add some styling to the web page.
js/main.js: The frontend JavaScript that interacts with the backend API.

How to Run the Application

First, make sure you have Node.js installed on your computer.
Download or clone the project files to your local machine.
Open a terminal and navigate to the project's directory.
Run npm install to install the required dependencies.
Start the server with node server.js.
Open your browser and visit http://localhost:8000.
Enter a string in the input box and click the "Check" button to see if it's a palindrome.

Backend Logic: Palindrome Check

Here is a simplified explanation of how the server handles palindrome checks:

function isPalindrome(str) {
	let copy = str.toLowerCase().split("").reverse().join("");
	return str.toLowerCase() === copy; // true or false
}

else if (page == "/api") {
	if ("palindrome" in params) {
		const word = params["palindrome"];
		if (word !== "") {
			const isWordPalindrome = isPalindrome(word);
			res.writeHead(200, { "Content-Type": "application/json" });
			res.end(JSON.stringify({ result: isWordPalindrome }));
		} else {
			res.writeHead(400, { "Content-Type": "application/json" });
			res.end(JSON.stringify({ error: "Please enter a word to check." }));
		}
	}
}

In this part of the code, when a request comes to the /api endpoint, the server checks if there is a palindrome parameter in the query string. If the parameter is there and not an empty string, the server runs the isPalindrome function to check if the word is a palindrome and sends the result back as a JSON object. If the parameter is missing or an empty string, the server responds with an error message, guiding the user to enter a word.

Project Demo

Below is a gif demonstrating how the project works. You can see how the user inputs a word, clicks the "Check" button, and immediately receives feedback on whether the word is a palindrome or not.

Conclusion

This project was a fantastic opportunity for me to dive into backend development, learn about server-side logic, and understand how to interact with APIs. I now feel more confident in my abilities to create backend functionalities and look forward to applying these learnings in future projects.