Achieving Basic Long Polling Implementation

Long Polling is a polling technique that keeps connections open for an extended period, facilitating instant response when server updates become available. Its implementation can be quite straightforward.

Apache as a Request Handler

To serve requests using Apache, create a PHP script like msgsrv.php. Here's a simple example:

// Simulate data availability after a random delay
sleep(rand(2, 10));
echo("Hi! Here's a random number: " . rand(1, 10));

Run this script on Apache. Note that using a high-volume webserver like Apache may result in exhausted worker threads.

Using a JavaScript Script

In JavaScript, you can use a script like long_poller.htm to initiate polling requests:

This script continuously makes requests to msgsrv.php, displaying responses in a div. It uses a simple rate limiter to prevent excessive requests.

Benefits of Long Polling

Long Polling offers resilience and simplicity. In case of network interruptions, the client retries automatically. It's a suitable choice for applications requiring immediate updates from the server, such as instant messaging or chat applications.