#Nodejs cache how to
#Nodejs cache code

Then, after the network call returns, probably 10-50ms later, the invisible magic calls the callback function. Because the callback has not yet been invoked, the cacheResp has not yet been set! So you see an empty cache. There is some invisible magic (it's not important to understand what/how) that will trigger the callback ~later~, but line 7 is done. At this point, line 7 has executed in its entirety. So, the cache.get() kicks off some work, and. This pattern is known as asynchronous JavaScript. The important thing to know is that because there is a callback function, the results of the cache.get() will be sent back via a callback. You may wonder, Which remote system? Where is the remote system? That's not important right now. This network call is sending out a request to a remote system. It's just doing in-memory things in JavaScript. The amount of time required to execute lines 1-6 is. The effect of lines 2-5 is to define a function. In the above (modified) code, lines 1-6 get executed.

#Nodejs cache code

Your code is like this: var cacheResp = Ĭonsole.log('**** Cache 1: **** ' + cacheResp) Ĭonsole.log('**** Cache 2: **** ' + cacheResp) īy using a named function for the callback, we could rewrite it to this: /* 1 */ var cacheResp = The callback function gets called *later*. What that means is, it returns *immediately*. Our cache middleware is the following.Īpp. We’ll make use of memory-cache npm module in order to be able to add content to cache. Our goal here is to enable server-side cache for our application with minimal effort.

#Nodejs cache how to

There are many ways of doing it, it could be done with NGINX or a CDN like CloudFlare, but in this example we’ll see how to do it with Node.js and Express with minimal work and in a flexible way. In our example above, the first request that reaches our server would still take 2 seconds to generate the HTML, but the following requests would hit the cache instead and the server would be able to send the response in a few milliseconds. The goal of server-side cache is responding to the same content for the same request independently of the client’s request.

This is where server-side cache comes in handy.

Think about the home page of a large news portal, do they process their HTML over and over again for each visitor? But, what if we have a complex and heavy page that takes 2 second to generate the HTML output? Even if we enable client-side cache for this page, the web server will still need to render the page for each different user accessing our web application. When dealing with web applications we can make good use of client side caching using response headers which all browsers currently support. About server-side cacheĬaching is a commonly used technique to improve the performance of any application, be it desktop, mobile or web. The framework’s middleware architecture makes it easy to plug-in extra features with minimal effort and in a standardized way.įor this article we’ll cover a very small and simple, yet powerful and useful middleware that will help you boost your express web application performance without any external dependency. Express is the most extensible web framework I’ve seen so far.