ProjectEngine is a piece of server software that retrieves files on request - much like a standard web server - but can also run computations before serving up an output file. This provides a versatile environment for doing computing on a shared server.
ProjectEngine is currently packaged as a component of WorkingWiki, though it is capable of being used independently.
To do: documentation of the internal design of WorkingWiki and ProjectEngine.
See also: ProjectEngine/URIs - specification of the URI scheme used by PE.