Telnet, SSL Telnet, SSH, and secure REPLs for use by hexagram30 projects
Start up the terminal project's components (including an SSL/encrypted Telnet server and a regular, unencrypted Telnet server):
$ lein start
To connect to the regular server, you may use any MUSH/MUD client or telnet
itself, e.g.:
rlwrap telnet localhost 1123
To connect to the encrypted Telnet server on Debian-based Linux, you can use
the SSL-enabled telnet program:
telnet-ssl -z ssl localhost 1122
For other operating systems, you can use netcat:
rlwrap ncat --telnet --ssl -n 127.0.0.1 1122
For use as part of a component-based system, see src/hxgm30/terminal/components/.
Note: SSH is not yet supported.
The telnet server instances (regular and SSL-encrypted) in this project both
utilize the Netty Java library. In addition, a Clojure server
namespace is provided that offers a straight-forward means of initializing,
starting, and stopping a telnet server with the respective public functions:
init, start, and stop.
High-level (Clojure API) initialization is responsible for setting up the
connection groups: one group for the "boss" thread that will be responsible for
accepting an incoming connection, and one group for the "worker" thread(s) that
will handle the traffic for the connection. Though it is possible to call init
manually, passing in options for the thread counts, by default init is called
by start and uses configuration to set the thread counts.
While calling init is optional, calling start is required. This function is
responsible for calling init if you haven't already, and for bootstrapping the
given telnet server. start returns the event loops from the call to init
(or the ones that were provided manually), and it is these event loops that are
passed to stop when it is time to shutdown the server.
The bootstrapping process is the code that's responsible for setting up the telnet initializer. One initializer is created for each telnet server, but its methods are called on a connection-by-connection basis: most important of these is the method that initializes the Netty channel.
In turn, the most important thing the channel initialization does is set up the handler that will respond to new lines sent over the wire.
The handler is responsible for several key actions:
- responding to when the channel first becomes active (this is usually where a banner/welcome screen is sent to the user)
- responding when a message is received
- flushing the context
- handling exceptions in communication
This is the part of the terminal code that ties into the shell implementations.
A donation account for supporting development on this project has been set up on Liberapay here:
You can learn more about Liberapay on its Wikipedia entry or on the service's "About" page.
Copyright © 2018, Hexagram30 <[email protected]>
Apache License, Version 2.0