A wApp registers at the Spark webserver (SSVR) asking to handle an url (can be a host name or a path) If the registration is accepted all requests concerning this url are forwarded to the registered application, that processes them, creates the reponse and transmits it back to the webserver, that forwards it back to the client.
The application/webserver comunication is achieved through TCP/IP: this allow the Spark webserver to be on a different server than the application. The same url family can be handled by more than an instance of the application: a number of instances of the application can run on different servers, and the requests are dispatched each time to a different application instance, allowing load balancing. The IP addresses from which an application can register can be restricted.
The applications are created deriving from the Spark wApp Framework.
The Spark wApp Framework (SWAF) handles the communication with the Spark http server (SSVR), handles the
site structure and handles the templating system and offers some services (as periodic function calls...)
to the wApps