How to Fetch Domain Information Using WHOIS API in JavaScript

Fetching WHOIS Information Using WHOIS API in JavaScript

• **Install Required Packages**: To work with APIs in JavaScript, particularly in a Node.js environment, you will need Node.js installed on your machine. Additionally, you'll need to install packages to make HTTP requests. The `axios` package is a popular choice. Run the following command to install it:

npm install axios

• **Set Up Environment Variables**: While working with APIs, you will often need to use an API key for authentication. Store this in an environment variable to keep it secure and to facilitate easy configuration switches between development and production environments.

require('dotenv').config(); // Ensure you have the dotenv package installed
const WHOIS_API_KEY = process.env.WHOIS_API_KEY;

• **Create a Function to Fetch Domain Information**: You will need to create a function that takes a domain as input and then makes an HTTP GET request to the WHOIS API endpoint. Make sure to handle the response and any potential errors appropriately. Here is an example using `axios`:

const axios = require('axios');

async function fetchDomainInfo(domainName) {
  const apiEndpoint = `https://api.example.com/whois?domain=${domainName}&apiKey=${WHOIS_API_KEY}`;

  try {
    const response = await axios.get(apiEndpoint);
    const domainInfo = response.data;
    
    return domainInfo;
  } catch (error) {
    console.error('Error fetching domain information:', error);
    throw error;
  }
}

• **Parse and Use the Data**: After fetching the domain information, you might need to parse it to extract specific details like domain status, registrant contact details, expiry dates, etc. Make sure you understand the structure of the WHOIS data returned and code accordingly.

async function displayDomainInfo(domainName) {
  try {
    const domainInfo = await fetchDomainInfo(domainName);
    
    console.log('Domain Name:', domainInfo.domainName);
    console.log('Registrar:', domainInfo.registrarName);
    console.log('Created On:', domainInfo.createdDate);
    console.log('Expires On:', domainInfo.expiryDate);
    // Continue with other data fields as necessary
  } catch (error) {
    console.error('Could not retrieve domain information:', error);
  }
}

// Example usage
displayDomainInfo('example.com');

• **Error Handling and Logging**: Implement robust error handling to manage potential issues such as network errors, API throttling, or unreachable endpoints. Additionally, include logging to track requests for auditing and debugging purposes.

const fs = require('fs');

function logError(error) {
  fs.appendFile('error.log', `${new Date()}: ${error}\n`, (err) => {
    if (err) console.error('Failed to log error:', err);
  });
}

async function fetchDomainInfoWithLogging(domainName) {
  try {
    return await fetchDomainInfo(domainName);
  } catch (error) {
    logError(error);
    throw error;
  }
}

• **Security and Performance Considerations**: Be aware of API rate limits and ensure that your application handles them gracefully. Also, consider caching responses for frequently queried domains to reduce the number of API calls. Always handle API keys and other credentials securely to prevent unauthorized access.

const cache = new Map();

async function getCachedDomainInfo(domainName) {
  if (cache.has(domainName)) {
    console.log('Returning cached data for', domainName);
    return cache.get(domainName);
  }

  const domainInfo = await fetchDomainInfoWithLogging(domainName);
  cache.set(domainName, domainInfo);

  return domainInfo;
}