Quick Guide to Realtime Data in Walmart without Webhooks

Aug 11, 2024 • 6 minute read

Hey there, fellow JavaScript devs! Ready to dive into the world of real-time Walmart data without the luxury of webhooks? Don't worry, we've got you covered. In this guide, we'll walk through how to set up a robust polling mechanism to keep your integration up-to-date with the latest from Walmart's API. Let's get started!

Setting up the Walmart API Client

First things first, let's get our API client set up. Assuming you've already got your Walmart API credentials, here's a quick snippet to get you going:

const axios = require('axios');
const crypto = require('crypto');

const walmartClient = axios.create({
  baseURL: 'https://marketplace.walmartapis.com',
  headers: {
    'WM_SEC.ACCESS_TOKEN': process.env.WALMART_ACCESS_TOKEN,
    'WM_QOS.CORRELATION_ID': crypto.randomUUID(),
    'Accept': 'application/json',
    'Content-Type': 'application/json'
  }
});

Implementing the Polling Mechanism

Now, let's set up our polling function. We'll use a simple interval to repeatedly check for new data:

const POLL_INTERVAL = 60000; // 1 minute

function startPolling() {
  setInterval(async () => {
    try {
      await fetchWalmartData();
    } catch (error) {
      console.error('Polling error:', error);
      // Implement retry logic here if needed
    }
  }, POLL_INTERVAL);
}

Fetching Data from Walmart API

Let's fetch some data! We'll use the orders endpoint as an example:

async function fetchWalmartData() {
  const response = await walmartClient.get('/v3/orders', {
    params: {
      createdStartDate: getLastPollTime(),
      limit: 100
    }
  });
  
  processOrders(response.data.list);
  updateLastPollTime();
}

Processing and Storing Data

Once we've got our data, let's process and store it:

function processOrders(orders) {
  orders.forEach(order => {
    // Update your local database or state
    updateOrderInDatabase(order);
    
    // Notify your UI
    notifyUIOfNewOrder(order);
  });
}

Optimizing Polling Performance

To keep things smooth, let's implement some adaptive polling:

let pollInterval = 60000;

function adjustPollInterval(orderCount) {
  if (orderCount > 50) {
    pollInterval = Math.max(pollInterval / 2, 30000);
  } else if (orderCount === 0) {
    pollInterval = Math.min(pollInterval * 2, 300000);
  }
}

Notifying the User Interface

Keep your UI in sync with events:

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

function notifyUIOfNewOrder(order) {
  orderEmitter.emit('newOrder', order);
}

// In your UI code
orderEmitter.on('newOrder', (order) => {
  // Update your UI here
  updateOrderList(order);
});

Best Practices and Considerations

Remember to handle network issues gracefully:

async function fetchWalmartData() {
  try {
    const response = await walmartClient.get('/v3/orders', {
      params: {
        createdStartDate: getLastPollTime(),
        limit: 100
      },
      timeout: 5000 // Set a reasonable timeout
    });
    
    processOrders(response.data.list);
    updateLastPollTime();
  } catch (error) {
    if (error.response) {
      console.error('API error:', error.response.status, error.response.data);
    } else if (error.request) {
      console.error('Network error:', error.message);
    } else {
      console.error('Error:', error.message);
    }
    // Implement exponential backoff here
  }
}

Conclusion

And there you have it! You're now equipped to handle real-time Walmart data like a pro, even without webhooks. Remember, polling isn't perfect, but it's a solid solution until Walmart rolls out webhook support (fingers crossed!).

Keep an eye on your API usage, stay within rate limits, and don't be afraid to tweak your polling intervals based on your specific needs. Happy coding!

Additional Resources

Now go forth and build some awesome Walmart integrations! 🚀