Architecture

FrePPLe has a 3-tier architecture, typical for most web applications.

• Browser based front-end:

  The user interface is completely web browser based, using state of the art web techniologies such as HTML5 and ajax.

  FrePPLe supports most modern browsers: Google Chrome, Firefox, Safari, Internet Explorer(>=10) and Opera.
• Web server:

  The web server retrieves data from the database and serves the content as HTML pages to the user.

  FrePPLe supports the Apache web server, and also has a built-in Python-based web server.

  Long running tasks (such as the planning algorithm, database backup, scenario copying, ...) don’t run in the web server process. Instead, the web server will spawn a separate worker process to execute these.
• Database backend:

  The planning data are stored in a PostgreSQL relational database.

  The database schema is simple and stable, which makes is possible to integrate with external applications directly at the database level.

A special use case is to use frePPle as a backend planning engine without user interface. In this case the planning engine can be embedded in another system. Users use the other system as the front-end, and frePPLe’s algorithms are used in the back-end to generate the plans.