WebSocket is a communication protocol used for efficient full-duplex communication between web browsers and servers over Transmission Control Protocol (TCP).

In this article, we will take a look at the history of the technologies used in dynamic websites. Then, we will introduce WebSocket as the modern approach in fulfilling these requirements while fixing the shortcomings of earlier techniques.

We will use the Ballerina language to demonstrate how you can effectively use the WebSocket features.

The Dynamic Web: Looking Back

HTTP is commonly used for a typical request / response scenario. Using JavaScript, the  XMLHTTPRequest object (and now the  Fetch API) helped send requests from the client to servers in the background. This allows us to execute data operations without refreshing or loading another web page.

However, this didn’t support the need for server push scenarios, where requests are initiated from the server and sent to the client. So people came up with workarounds to make it possible.

A couple of those options are polling and long polling.

Regular polling works by creating a new HTTP connection that sends a request to the server looking for new updates. If there is any communication that needs to be done from the server to the client, the server will at this point return the message to the client. In the event there is nothing new, the server will reply saying so. Following the response from the server, the connection will be closed.

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