net-repl : A Network Read-Eval-Print Loop

_net-repl_ : A Network Read-Eval-Print Loop
===========================================

By the Untyped Dudes
    Noel Welsh   (noel at untyped dot com)
    Dr D Gurnell (daveg at untyped dot com)

Keywords: _net-repl_, _repl_, _read-eval-print_,
	  _read-eval-print loop_


Introduction
============

The net-repl library provides a REPL that reads from and
writes to a TCP network port, instead of the usual console
IO.  This is useful if you wish to interact with a long
running program, such as a web-server, that does not have a
console.


Usage
=====

Somewhere in your program add the following lines:

  (require (planet "net-repl.ss" ("untyped" "net-repl.plt" 1)))
  (run-net-repl)

You will now have a REPL running on port 9876 (see the API
documentation for how you can change the port).  Just telnet
to this port from the same machine running the REPL and type
away.  Type

  (close)

to close your connection when you've finished.


Security & Other Warnings
-------------------------

The net REPL only allows access from the localhost
(127.0.0.1).  However anyone with shell access to your
machine can access the REPL.  Therefore don't run the net
REPL on a public machine.

If you run

  (exit)

you'll quit the entire MzScheme process.  This can be
useful, but can also unexpectedly bring down your server.
Be careful!


net-repl API
============

> (with-net-repl-port [port-k])
with-net-repl-port : (parameter-of natural)

A natural number giving the port the net REPL should listen
to.  Defaults to 9876.


> (with-net-repl-timeout [timeout])
with-net-repl-timeout : (parameter-of (U natural #f))

The time, in seconds, that a connection thread is allowed to
run before it is terminated, or #f indicating connections
can run forever.  Defaults to #f.

> (run-net-repl)
run-net-repl : () -> thread-descriptor

Runs the net REPL server is a new thread.  Returns the
thread-descriptor of the net REPL thread.