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

PHP is not a good fit for your requirements (in a normal setup like apache-php, fastcgi etc.), because the PHP script gets executed from top to bottom for every request and cannot maintain any state between the requests without the use of external services or databases/files (Except e.g. http://php.net/manual/de/book.apc.php, but it is not intended for implementing a chat and will not scale to multiple servers.)

You should definitely look at Node.js and especially the Node.js module Socket.IO (A Websocket library). It's incredibly easy to use and rocks. Socket.IO can also scale to multiple chat servers with an optional redis backend, which means it's easier to scale.

Trying to use $_SESSION with a static session id as communication channel is not a solution by the way, because PHP saves the session data into files.