In modern web applications, it is common to have data stored locally on the client-side using technologies like IndexedDB. However, there may be scenarios where you need to synchronize this locally stored data with a remote server or system, such as Apache Kafka. In this blog post, we will explore how to implement data synchronization between IndexedDB and Apache Kafka.

Prerequisites

Before getting started, make sure you have the following in place:

1. A basic understanding of IndexedDB and Apache Kafka.
2. Node.js and npm installed on your machine.

Step 1: Setting up IndexedDB

First, we need to set up IndexedDB in our web application to store and retrieve data locally. Here’s an example code snippet to create an IndexedDB database and add data to it:

const request = indexedDB.open('myDatabase', 1);

request.onupgradeneeded = function(event) {
  const db = event.target.result;
  const objectStore = db.createObjectStore('myObjectStore', { keyPath: 'id' });
};

request.onsuccess = function(event) {
  const db = event.target.result;
  const transaction = db.transaction(['myObjectStore'], 'readwrite');
  const objectStore = transaction.objectStore('myObjectStore');
  
  const data = { id: 1, name: 'John Doe', age: 30 };
  const addRequest = objectStore.add(data);

  addRequest.onsuccess = function(event) {
    console.log('Data added to IndexedDB');
  };
};

Step 2: Writing a Kafka Producer

Next, we need to write a Kafka producer that sends the data from IndexedDB to the Kafka broker. We can use the kafkajs library for this purpose. Install the library using the following command:

npm install kafkajs

Here’s an example code snippet for the Kafka producer:

const { Kafka } = require('kafkajs');

const kafka = new Kafka({
  clientId: 'my-producer',
  brokers: ['localhost:9092']
});

const producer = kafka.producer();

async function sendToKafka(topic, data) {
  await producer.connect();
  await producer.send({
    topic,
    messages: [
      { value: JSON.stringify(data) }
    ]
  });
  await producer.disconnect();
}

Step 3: Synchronizing Data

Now that we have our IndexedDB set up and a Kafka producer ready, we can synchronize the data by periodically fetching records from IndexedDB and sending them to Kafka.

One approach is to use a timer or a cron job to trigger the synchronization process. Here’s an example code snippet that synchronizes the data every 5 minutes:

setInterval(async () => {
  const db = await indexedDB.open('myDatabase');
  const transaction = db.transaction(['myObjectStore'], 'readonly');
  const objectStore = transaction.objectStore('myObjectStore');
  const cursor = objectStore.openCursor();

  await cursor.iterate(cursor => {
    sendToKafka('myTopic', cursor.value);
    cursor.continue();
  });
}, 5 * 60 * 1000);

Conclusion

By following these steps, you can implement data synchronization between IndexedDB and Apache Kafka in your web application. With IndexedDB acting as a local data store and Apache Kafka handling the data synchronization with the server-side, you can provide a seamless and efficient data synchronization experience for your users.

#dataSync #ApacheKafka