How do Lightning Components interact with Salesforce?

Hi All,

Today one of my blog visitor asked me, how do Lightning Components interact with Salesforce? How does Lightning component get data from server? I thought to write an article on this, it might help you also to understand the architecture of Lightning Component Framework.

Below image will help you in understanding this.

 

1. Whenever a Lightning Component or an App runs on browser of Mobile device, it first download all component resources(i.e. Styles, Scripts, Markup) on mobile device. They are contained in browser’s memory to support display and processing that is why we call it client-side.
2. Now if you want to call a apex method from client side, you will fire an event on client side. This event will call a JavaScript method on client-side. This client-side method will make an HTTP requests to Salesforce to call apex method on server-side. Like you do in VisualForce using action function or other JavaScript.
3. This HTTP request to call apex method will be asynchronous. Asynchronous means you will make the request and forget about it and the controller returns to the client. The processing will be done on server-side.
4. In the meantime Salesforce processes the logic by executing some apex.
5. Finally when it is done with processing and gets some resulted data or not, it makes a callback to the browser/client-side. The client response by invoking an associated JavaScript callback function which extract data passed back by apex methods. This data can be assigned to component attributes. Now display will be automatically refreshed.

Hope this will be helpful 🙂