In today’s technological landscape, performance is crucial for delivering efficient and responsive web applications. One way to improve performance is by implementing a caching system, which stores frequently accessed data for faster retrieval. In this blog post, we’ll explore how to implement a proxy-based distributed caching system in JavaScript.

Why Proxy-based Distributed Caching?

Traditional caching systems typically rely on a centralized server to store and retrieve cached data. While this can work well for small-scale applications, it can become a bottleneck when dealing with high volume and distributed systems. A proxy-based approach allows us to distribute the caching across multiple servers, enabling better scalability and improved performance.

Setting Up the Proxy Server

To begin, we need to set up a proxy server that will handle the caching functionality. We can use a popular Node.js package called ‘http-proxy’ for this purpose. Let’s install it using npm:

npm install http-proxy

Once installed, we can create our proxy server using the following code:

const httpProxy = require('http-proxy');
const cache = new Map(); // in-memory cache

const proxy = httpProxy.createProxyServer({});

proxy.on('proxyRes', function (proxyRes, req, res, options) {
  const { path } = req; // extract request path
  if (!cache.has(path)) {
    cache.set(path, proxyRes); // cache the response
  }
});

proxy.on('proxyReq', function (proxyReq, req, res, options) {
  const { path } = req; // extract request path
  if (cache.has(path)) {
    // serve cached response if available
    const cachedRes = cache.get(path);
    res.setHeader('Content-Type', cachedRes.headers['Content-Type']);
    res.end(cachedRes.body);
  }
});

proxy.listen(3000); // start the proxy server

How it Works

Our proxy server intercepts incoming requests using the proxyReq event. If the requested data is already cached, we serve the cached response instead of forwarding the request to the origin server. We use an in-memory cache implemented as a Map object for simplicity, but you can replace it with a more advanced caching mechanism like Redis if needed.

For each response from the origin server, we capture it using the proxyRes event. We then store the response in the cache using the request path as the key. This ensures that subsequent requests for the same path will be served from the cache without hitting the origin server.

Integrating with your Web Application

To integrate the caching system with your web application, you’ll need to configure your application server to forward requests to the caching proxy server. This can usually be achieved by setting up a reverse proxy, such as Nginx, that forwards requests to the proxy server.

By implementing a proxy-based distributed caching system, you can significantly improve the performance and scalability of your web application. Cached responses can be served directly from the cache, reducing the load on your origin server and improving response times.

#distributedcaching #proxycaching