Understanding Long Polling

Introduction#

Long Polling is a technique used in web development to achieve real-time communication between a client and a server. It's a predecessor to technologies like WebSockets and Server-Sent Events (SSE). In this lesson, you'll explore how Long Polling works and its role in enabling asynchronous communication.

The Basics of Long Polling#

Long Polling revolves around the idea of keeping a connection open for an extended period, waiting for new information to be available. Instead of the traditional request-response model, where the client repeatedly polls the server for updates, Long Polling involves the server holding onto a request until new data is ready to be sent.

How Long Polling Works Step by Step#

1. Client Requests Information:

   • The process begins with the client sending a regular HTTP request to the server, typically using AJAX.

2. Server Holds the Request:

   • The server receives the request and holds onto it without immediately responding.

   • Once new data is available, the server responds to the waiting request with the updated information.

3. Client Processes Data:

   • The client processes the received data and immediately initiates a new request to keep the connection open.

4. Repeat the Process:

   • The cycle repeats, with the client continuously polling the server for updates.