GNU Prolog-PHP multi-tier integration

The paper provides a concept of GNU-Prolog integration with PHP using ANSI C socket server as a middleware. Web application programming becomes more and more important issue. The meaning of HTTP based applications grows together with popularity of the internet. There ware a few methods of integration web programming together with CLP proposed so far. The simplest and most obvious way is to run CLP program in CGI mode, but it has disadvantages as well. For some appliance CLP programs can have long execution time that could cause web server timeouts. For that reason a new approach is proposed: to separate user interface (web based) from CLP program execution. That goal is achieved by means of socket server written in ANSI C. One of popular CLP tools used in general purpose is the GNU-Prolog, besides it is quite well documented and distributed under convenient license too. Together with PHP scripts it could give users powerful and easy to use environment to build web based applications that use CLP technique. The present paper describes the attempt of finding a good way to work PHP together with GNU-Prolog.