Aikido example web server
-------------------------

This example shows a simple but functional HTTP server.
It serves up the usual mix of file types to a
browser and adds a feature called 'Aikido Server
Pages'.  This is different from the usual
idea of server pages where the server processes
special comments in the html source to get
different effects.

Aikido Server Pages are like a light-weight
CGI program - it produces HTML as output.  When 
the server is asked to serve up a page with
the extension '.aikidosp' it loads the page
into the server and executes it as an aikido
script.  The script has to provide a function
called 'send' taking 2 arguments as follows:

public function send (url, httpstream) {
}

The first argument is the URL object representing
the sender of the request.  This contains a
number of facilities, such as the arguments
supplied to the URL.  See the file url.aikido
for full details of the URL object.

The second argument is a stream through which
the script may send data.  This is a stream
that formats the data using the HTTP protocol.

Typically, the script will create an instance
if the class HTML.Page.  This object understands
how to format html data.  See the file htmlpage.aikido
for information on what is avialable.

Running the server
------------------

The server runs on port 8000 of the local machine.
To test it, run the server by:

% aikido webserver

The go to a browser and type the url of the local
machine specifying port 8000.  Something like this
will probably work:

http://localhost:8000


User directories
----------------

If the file portion of the incoming URL starts with
a tilde (~) then the following name is taken as
the name of a user of the system.  The server will
look for a file called 'index.html' (and others)
in the public_html sub-directory of the user's
home directory.

If the file index.html doesn't exist then the following
files are searched for, in the order given:

index.shtml
index.htm
index.aikidosp

Threading
---------

The server runs in a multithreaded mode.  When the program
starts, it spawns a set of threads whose sole purpose
in life is to process incoming HTTP requests.  When a
request is received, a thread is woken up and assigned
to the request.  There is a maximum of 10 requests that
can be processed at once (the constant MAX_REQUESTS in
the webserver.aikido file).

If too many requests arrive at the same time, the threads
will get around to processing them in the order in which
they were received.


Limitations
-----------

This is an example program and is not meant to be a full
web server.  It does not support authentication of the
user in any way.  It probably has some bugs too...