App Webserver As a Functor

Example code demonstrating how SML modules, in particular functors, can be used for structuring a web framework.

The code in its current state is only useful for demonstration, it is not ready for production. Also, it's probably a bit far fetched to call the current code a "framework".

Architecture

The overall idea is that you make a web-application by implementing a structure, say App, with the signature WebApp. Then you give App to a functor which will then take care of creating a web server (or in communicate with one).

The framework consists of two files:

• HtmlUtils.sml contains a structure HtmlUtils where the type reply for HTTP replies is declared, the module also contains some simple-mined (read inefficient) utility functions for creating HTML pages.

• WebServerFct.sml contains the signature WebApp and the functor WebServerFct.

Examples

Compile the examples with the command:

$ mosmlc -toplevel HtmlUtils.sml WebServerFct.sml App.sml -o appserver

Where App.sml is the example you want to compile.

• CountingEcho.sml an echo server, that also counts how many times it has been called.

• PhonebookApp.sml an phonebook with shared state across clients. Uses an in-memory "database" implemented as a list.

  Shows how to deal (rudimentary) with the query path of an URL (http://en.wikipedia.org/wiki/Query_string).