Unique Chat Implementation using PHP, AJAX, and JSON
I have developed a unique chat application after researching various resources like tutorials and books. One of the valuable resources that I relied on is a book/tutorial called "AJAX and PHP: Building Responsive Web Applications: Chapter 5: AJAX chat and JSON". You can access it by visiting this link: AJAX and PHP: Building Responsive Web Applications: Chapter 5: AJAX chat and JSON. This resource provided me with step-by-step instructions to create a complete chat script.
Innovative Approach - Comet based Chat Integration
Apart from traditional AJAX-based methods, I also explored the concept of "Comet" in combination with PHP for building a more responsive chat system. I came across an informative article by zeitoun titled "Comet and PHP" which explains how Comet enables web servers to send data to clients without the need for client requests. You can learn more about it by visiting this link: zeitoun.
I will share two different ways to implement Comet with PHP:
- An approach based on hidden iframes using server timestamps
- An alternative method using classic AJAX non-returning requests
The first method allows real-time display of the server time on clients while showcasing a mini-chat. To implement this method, you will require a backend PHP script named "backend.php", a frontend HTML script containing the JavaScript code named "index.html", and either the Prototype JS library or jQuery.
The backend script ("backend.php") is responsible for handling persistent HTTP requests by creating an infinite loop that continuously returns the server time as long as the client is connected. On the other hand, the frontend script ("index.html") creates a "comet" JavaScript object that connects the backend script to the time container tag on the webpage.
Method 1: iframe + server timestamp
<?php
header("Cache-Control: no-cache, must-revalidate");
header("Expires: Sun, 5 Mar 2012 05:00:00 GMT");
flush();
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Comet php backend</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
<script type="text/javascript">
var comet = window.parent.comet;
</script>
<?php
while(1) {
echo '<script type="text/javascript">';
echo 'comet.printServerTime('.time().');';
echo '</script>';
flush();
sleep(1);
}
?>
</body>
</html>
Innovative Approach - AJAX non-returning request
Similar to the previously mentioned method, this approach also requires a backend PHP script named "backend.php", a frontend HTML script containing the JavaScript code named "index.html", and a data exchange file named "data.txt". However, in addition to handling the persistent HTTP requests for displaying server time, the backend script ("backend.php") performs two additional tasks. It writes new chat messages into the "data.txt" file and creates an infinite loop until the "data.txt" file is modified.
Alternatively
If you are interested in exploring other unique chat applications, I recommend checking out the following resources:
- BlaB! Lite: An AJAX-based chat system that supports MySQL, SQLite & PostgreSQL databases and can be viewed with any browser.
- Gmail/Facebook Style jQuery Chat: A jQuery chat module that seamlessly integrates Gmail/Facebook style chat into your existing website.
- Writing a JavaScript/PHP Chat Server: A tutorial on creating a JavaScript/PHP chat server implementation.
- CometChat: A chat solution that runs on shared servers and only requires PHP + mySQL.