Quick Guide to Realtime Data in Realtor.com Connections Plus without Webhooks

Aug 11, 2024 • 7 minute read

Hey there, fellow Javascript devs! Ready to dive into the world of real-time data fetching from Realtor.com Connections Plus API? Great! We're going to explore how to keep your real estate app up-to-date using good old polling instead of webhooks. Let's get started!

Setting Up Your Environment

First things first, make sure you've got Node.js installed and your Realtor.com API credentials handy. We'll be using axios for our HTTP requests and dotenv for managing environment variables. Go ahead and install them:

npm install axios dotenv

Implementing the Polling Mechanism

Alright, let's build our polling function. Here's a simple example to get us started:

const axios = require('axios');
require('dotenv').config();

const poll = async (interval) => {
  while (true) {
    try {
      await fetchData();
      await new Promise(resolve => setTimeout(resolve, interval));
    } catch (error) {
      console.error('Polling error:', error);
    }
  }
};

Fetching Data from the API

Now, let's create our fetchData function to actually grab the data from Realtor.com:

const fetchData = async () => {
  const url = 'https://api.realtor.com/connections-plus/v1/listings';
  const headers = {
    'Authorization': `Bearer ${process.env.REALTOR_API_KEY}`,
    'Content-Type': 'application/json'
  };

  try {
    const response = await axios.get(url, { headers });
    return response.data;
  } catch (error) {
    throw new Error(`API request failed: ${error.message}`);
  }
};

Efficient Polling Strategies

To be a good API citizen and avoid rate limits, let's implement an adaptive polling interval:

let pollInterval = 5000; // Start with 5 seconds

const adaptivePolling = async () => {
  while (true) {
    try {
      const startTime = Date.now();
      const data = await fetchData();
      const endTime = Date.now();

      processData(data);

      // Adjust polling interval based on response time
      pollInterval = Math.max(5000, (endTime - startTime) * 2);
      
      await new Promise(resolve => setTimeout(resolve, pollInterval));
    } catch (error) {
      console.error('Polling error:', error);
      // Increase interval on error
      pollInterval = Math.min(pollInterval * 2, 60000);
    }
  }
};

Processing and Storing Data

Let's process our fetched data and compare it with what we already have:

let lastData = null;

const processData = (newData) => {
  if (JSON.stringify(newData) !== JSON.stringify(lastData)) {
    console.log('New data received!');
    lastData = newData;
    updateUI(newData);
  }
};

Updating the User Interface

Here's a simple event emitter to trigger UI updates:

const EventEmitter = require('events');
const uiEmitter = new EventEmitter();

const updateUI = (data) => {
  uiEmitter.emit('update', data);
};

// In your UI code
uiEmitter.on('update', (data) => {
  // Update your UI here
  console.log('Updating UI with new data');
});

Error Handling and Retry Logic

Let's implement some retry logic with exponential backoff:

const retry = async (fn, maxRetries = 3, delay = 1000) => {
  for (let i = 0; i < maxRetries; i++) {
    try {
      return await fn();
    } catch (error) {
      if (i === maxRetries - 1) throw error;
      await new Promise(resolve => setTimeout(resolve, delay * Math.pow(2, i)));
    }
  }
};

// Usage
const fetchWithRetry = () => retry(fetchData);

Performance Considerations

To minimize API calls, let's implement a simple caching strategy:

const cache = new Map();

const fetchWithCache = async (key) => {
  if (cache.has(key)) {
    const { data, timestamp } = cache.get(key);
    if (Date.now() - timestamp < 60000) { // 1 minute cache
      return data;
    }
  }
  
  const data = await fetchData();
  cache.set(key, { data, timestamp: Date.now() });
  return data;
};

Wrapping Up

And there you have it! You've now got a solid foundation for fetching real-time data from Realtor.com Connections Plus API using polling. Remember, while polling is great for many scenarios, always keep an eye on your API usage and consider optimizing as your app scales.

Keep experimenting and happy coding!