random php… a multi-channel chat rooom class using memcached for persistence

why? i dunno… just because… just a toy…

no sql, no flat file, no write permissions required anywhere, no fuss

class mc_chat {

        var $chan = null;
        var $mc = null;
        var $ret = 5;

        function __construct($memcached, $channel, $retention=5) {
                $this->mc = $memcached;
                $this->chan = $channel;
                $this->ret = $retention;
        }

        function messages( $from=0 ) {
                $max = (int)$this->mc->get("$this->chan:max:posted");
                $min = (int)$this->mc->get("$this->chan:min:posted");
                $messages = array();
                for ( $i=$min; $i< =$max; $i++ ) {
                        if ( $i < $from )
                                continue;
                        $m = $this->get($i);
                        if ( $m['user'] && $m['message'] )
                                $messages[$i] = $m;
                }
                return $messages;
        }

        function get($id) {
                return array(
                        'user' =>(string)$this->mc->get("$this->chan:msg:$id:user"),
                        'message' => (string)$this->mc->get("$this->chan:msg:$id"),
                );
        }

        function add($user, $message) {
                $id = (int)$this->mc->increment("$this->chan:max:posted");
                if ( !$id ) {
                        $id=1;
                        $this->mc->set("$this->chan:max:posted", 1);
                }
                $this->mc->set("$this->chan:msg:$id:user", (string)$user);
                $this->mc->set("$this->chan:msg:$id", (string)$message);
                if ( $id >= $this->ret ) {
                        if ( !$this->mc->increment("$this->chan:min:posted") )
                                $this->mc->set("$this->chan:min:posted", 1);
                }

        }

}

$mc = new Memcache;
$mc->connect('localhost', 11211);
$keep_messages = 10;
$chatter_id = 1;
$chat = new mc_chat($mc, 'chat-room-id', $keep_messages);
$chat->add($chatter_id, date("r").": $chatter_id : foo");
$chat->messages(37); // messages only above id=37
$chat->messages(); // all the latest messages

class mc_chat {

var $chan = null;

var $mc = null;

var $ret = 5;

function __construct($memcached, $channel, $retention=5) {

$this->mc = $memcached;

$this->chan = $channel;

$this->ret = $retention;

}

function messages( $from=0 ) {

$max = (int)$this->mc->get("$this->chan:max:posted");

$min = (int)$this->mc->get("$this->chan:min:posted");

$messages = array();

for ( $i=$min; $i< =$max; $i++ ) {

if ( $i < $from )

continue;

$m = $this->get($i);

if ( $m['user'] && $m['message'] )

$messages[$i] = $m;

}

return $messages;

}

function get($id) {

return array(

'user' =>(string)$this->mc->get("$this->chan:msg:$id:user"),

'message' => (string)$this->mc->get("$this->chan:msg:$id"),

);

}

function add($user, $message) {

$id = (int)$this->mc->increment("$this->chan:max:posted");

if ( !$id ) {

$id=1;

$this->mc->set("$this->chan:max:posted", 1);

}

$this->mc->set("$this->chan:msg:$id:user", (string)$user);

$this->mc->set("$this->chan:msg:$id", (string)$message);

if ( $id >= $this->ret ) {

if ( !$this->mc->increment("$this->chan:min:posted") )

$this->mc->set("$this->chan:min:posted", 1);

}

$mc = new Memcache;

$mc->connect('localhost', 11211);

$keep_messages = 10;

$chatter_id = 1;

$chat = new mc_chat($mc, 'chat-room-id', $keep_messages);

$chat->add($chatter_id, date("r").": $chatter_id : foo");

$chat->messages(37); // messages only above id=37

$chat->messages(); // all the latest messages

3 thoughts on “random php… a multi-channel chat rooom class using memcached for persistence”

jenz 2009/02/17 at 12:09 AM

Pretty slick. I was actually looking for something like this last week

Reply ↓
Roy Klopper 2009/03/12 at 11:28 PM

Really nice and simple implementation of a chat adapter love it!

Reply ↓
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