Webbased chat in php without using database or file

Question

I am trying to implement a realtime chat application using PHP . Is it possible to do it without using a persistent data storage like database or file . Basically what I need is

Answer 1

One solution to achieving this is by writing a PHP socket server.

<?php

// Set time limit to indefinite execution

set_time_limit (0);

// Set the ip and port we will listen on

$address = '192.168.0.100';

$port = 9000;

$max_clients = 10;

// Array that will hold client information

$clients = Array();

// Create a TCP Stream socket

$sock = socket_create(AF_INET, SOCK_STREAM, 0);

// Bind the socket to an address/port

socket_bind($sock, $address, $port) or die('Could not bind to address');

// Start listening for connections

socket_listen($sock);

// Loop continuously

while (true) {

    // Setup clients listen socket for reading

    $read[0] = $sock;

    for ($i = 0; $i < $max_clients; $i++)

    {

        if ($client[$i]['sock']  != null)

            $read[$i + 1] = $client[$i]['sock'] ;

    }

    // Set up a blocking call to socket_select()

    $ready = socket_select($read,null,null,null);

    /* if a new connection is being made add it to the client array */

    if (in_array($sock, $read)) {

        for ($i = 0; $i < $max_clients; $i++)

        {

            if ($client[$i]['sock'] == null) {

                $client[$i]['sock'] = socket_accept($sock);

                break;

            }

            elseif ($i == $max_clients - 1)

                print ("too many clients")

        }

        if (--$ready <= 0)

            continue;

    } // end if in_array



    // If a client is trying to write - handle it now

    for ($i = 0; $i < $max_clients; $i++) // for each client

    {

        if (in_array($client[$i]['sock'] , $read))

        {

            $input = socket_read($client[$i]['sock'] , 1024);

            if ($input == null) {

                // Zero length string meaning disconnected

                unset($client[$i]);

            }

            $n = trim($input);

            if ($input == 'exit') {

                // requested disconnect

                socket_close($client[$i]['sock']);

            } elseif ($input) {

                // strip white spaces and write back to user

                $output = ereg_replace("[ \t\n\r]","",$input).chr(0);

                socket_write($client[$i]['sock'],$output);

            }

        } else {

            // Close the socket

            socket_close($client[$i]['sock']);

            unset($client[$i]);

        }

    }

} // end while

// Close the master sockets

socket_close($sock);

?>

You would execute this by running it through command line and would always have to run for your PHP clients to connect to it. You could then write a PHP client that would connect to the socket.

<?php
$fp = fsockopen("www.example.com", 80, $errno, $errstr, 30);
if (!$fp) {
    echo "$errstr ($errno)<br />\n";
} else {
    $out = "GET / HTTP/1.1\r\n";
    $out .= "Host: www.example.com\r\n";
    $out .= "Connection: Close\r\n\r\n";
    fwrite($fp, $out);
    while (!feof($fp)) {
        echo fgets($fp, 128);
    }
    fclose($fp);
}
?>

You would have to use some type of ajax to call with jQuery posting the message to this PHP client.

http://devzone.zend.com/209/writing-socket-servers-in-php/ http://php.net/manual/en/function.fsockopen.php

Answer 2

Just tried something I had never done before in response to this question. Seemed to work but I only tested it once. Instead of using a Socket I had an idea of using a shared Session variable. Basically I forced the Session_id to be the same value regardless of the user therefore they are all sharing the same data. From a quick test it seems to work. Here is what I did:

session_id('12345');
session_start();
$session_id = session_id();
$_SESSION['test'] = $_SESSION['test'] + 1;
echo "session: {$session_id} test: {$_SESSION['test']} <br />";

So my thought process was that you could simply store the chat info in a Session variable and force everyone regardless of who they are to use a shared session. Then you can simply use ajax to continually reload the current Session variable, and use ajax to edit the session variable when adding a message. Also you would probably want to set the Session to never expire or have a really long maxlifetime.

As I said I just played around with this for a few minutes to see if it would work.

Answer 3

Is it possible to do it without using a persistent data storage like database or file?

It is possible but you shouldn't use. Database or file based doesn't slows down chat. It will be giving additional security to your chat application. You can make web based chat using ajax and sockets without persistent data.

You should see following posts:

1. Is database based chat room bad idea?
2. Will polling from a SQL DB instead of a file for chat application increase performance?
3. Using memcached as a database buffer for chat messages
4. persistent data in php question
5. https://stackoverflow.com/questions/6569754/how-can-i-develop-social-network-chat-without-using-a-database-for-storing-the-c
6. File vs database for storage efficiency in chat app

Answer 4

You will want to use Sockets. This article will cover exactly what you want to do: http://devzone.zend.com/209/writing-socket-servers-in-php/

Answer 5

Better use a node.js server for this. WebSockets aren't cross-browser nowadays (except socket.io for node.js that works perfect)

Answer 6

You didn't say it had to all be written it PHP :)

Install RabbitMQ, and then use this chat implementation built on top of websockets and RabbitMQ.

Your PHP is pretty much just 'chat room chrome'. It's possible most of your site would fit within the 5 meg limit of offline HTML5 content, and you have a very flexible (and likely more robust than if you did it yourself) chat system.

It even has 20 messages of chat history if you leave the room.

https://github.com/videlalvaro/rabbitmq-chat