# httpsrv.h | documentation

    #charset "us-ascii"
    #pragma once

    /*
     *   Copyright 2010 Michael J. Roberts.
     *
     *   This file is part of TADS 3.
     *
     *   This module defines the HTTPServer intrinsic class.  This class is used
     *   to set up a network HTTP server, which has a number of potential
     *   applications:
     *
     *   - Run a game in a client/server configuration, so that the user
     *   interface is running in a Web browser on one machine, and the game
     *   itself is running on a separate server machine on the network.  This
     *   lets the game run on handheld devices that might be too slow to run the
     *   game directly, allows running the game without any software
     *   installation, and makes the game more portable by depending only on a
     *   browser being available rather than requiring a TADS interpreter.
     *
     *   - Run a game in with a browser-based UI, so that it can take advantage
     *   of HTML DOM and Javascript.  Modern browsers are more powerful than HTML
     *   TADS, so it's possible to create a more elaborate and customized game UI
     *   by running in a browser.
     *
     *   - Create a multi-user game, by running the game on a server and writing
     *   the game to accept connections from more than one player.
     */

    /*
     *   HTTP Server Object.  This implements a multi-threaded, background server
     *   that runs concurrently with the game program.  The server listens for
     *   and accepts incoming connection requests from clients, and then handles
     *   HTTP protocol transactions with connected clients.  Client requests are
     *   routed to the byte code program via network events, which the program
     *   can retrieve via the getNetEvent() function.
     *
     *   Construction: to set up an HTTP server, simply create an HTTPServer
     *   object with 'new':
     *
     *.     local srv = new HTTPServer(hostname, portnum?, maxUploadSize?);
     *
     *   'hostname' is a string giving the domain name or IP address that the
     *   server will bind to for accepting connections.  For a server that
     *   accepts connections from separate client machines, this is simply the
     *   external IP address of the local machine.  (This is specified as an
     *   argument because some machines have more than one network interface, and
     *   thus have more than one IP address or domain name.)
     *
     *   'portnum' is the TCP/IP port number wehre the server will listen for
     *   incoming connections.  If this is omitted or nil, the operating system
     *   will automatically select an available port number and assign it to the
     *   server.  Using a specific port number allows you to create a service on
     *   a "well known" port, which makes it easier for clients to find the
     *   service; but a given port can only be used by one server at a time, so
     *   using a pre-selected port number runs the risk that some other process
     *   will already be using the same port.
     *
     *   'maxUploadSize' is the maximum size in bytes for any single request's
     *   content.  Content sizes over this limit will be rejected.  Some HTTP
     *   requests, such as POST, can include uploaded content from the client,
     *   and the HTTP protocol itself supports essentially unlimited sizes for
     *   these objects.  Uploads consume resources on the server, though, so it's
     *   often desirable to set a size limit to prevent errant or malicious
     *   clients from overwhelming the server with a very large upload.
     *   Depending on the specific function of your server, you might or might
     *   not wish to set a limit.  If you omit this argument or set it to nil,
     *   unlimited upload sizes will be allowed.  Note that this limit applies to
     *   each individual upload separately; it's not a lifetime limit for the
     *   server or for any session.
     *
     *   Creating an HTTPServer object with 'new' automatically starts the
     *   server.  The object will create a background thread that will listen for
     *   incoming connections on the given network address and port number, so
     *   the server is active as soon as the 'new' finishes.  You can create any
     *   number of servers, as long as they have different port numbers.  When a
     *   connection request is received, the server will accept the connection
     *   and automatically create another background thread to handle requests on
     *   that connection.  Each incoming request will be forwarded to the game
     *   program to handle, via the network message queue.
     */
    intrinsic class HTTPServer 'http-server/030000': Object
    {
        /*
         *   Shut down the server.  This immediately disconnects the server from
         *   its network port; no further client connections will be accepted
         *   once the server shuts down.  In addition, all of the server threads
         *   that were started by this server object will be notified to
         *   terminate.
         *
         *   If 'wait' is omitted or is nil, the routine sends the shutdown
         *   notification to the main server and to its server threads, then
         *   immediately returns.  This means that one or more of the server's
         *   background threads might continue to run for a while after
         *   shutdown() returns.  The main practical consideration is that the
         *   port number used by the server might not be immediately available
         *   for use by a new server object, since the port won't be closed until
         *   the server actually exits.
         *
         *   If 'wait' is true, this routine won't return until all of the server
         *   threads have actually terminated.
         *
         *   The return value is true if all server threads have terminated, nil
         *   if any server threads are still running.  It's legal to call this
         *   routine repeatedly, so you can make repeated calls to shutdown(nil)
         *   to poll for completion.  This is useful if you need to wait until
         *   the server shuts down to move on to a next step, but you have other
         *   work you can perform in the meantime.  If you don't have any other
         *   work, you can avoid burning CPU time by calling shutdown(true),
         *   which waits (without consuming CPU time) for the server to exit.
         */
        shutdown(wait?);

        /*
         *   Get the listening address.  This returns a string giving the
         *   original binding address specified when the object was constructed.
         *   This can contain either a host name or an IP address, since either
         *   form can be used in the constructor.
         */
        getAddress();

        /*
         *   Get the listening IP address.  This returns the numerical IP address
         *   where the server is listening for connections.
         */
        getIPAddress();

        /*
         *   Get the port number.  This returns an integer giving the TCP/IP
         *   network port number on which this server is listening for incoming
         *   connections.  Clients connect to the port by including it in the
         *   HTTP URL, after the host name.  For example, if the server is on
         *   port 10815, the client would connect to a URL of the form
         *   http://myserver.com:10815/index.htm.
         */
        getPortNum();
    }

TADS 3 Library Manual
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