enigma-bbs/mods/telnet_bridge.js

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/* jslint node: true */
'use strict';
// ENiGMA½
const MenuModule = require('../core/menu_module.js').MenuModule;
const resetScreen = require('../core/ansi_term.js').resetScreen;
const setSyncTermFontWithAlias = require('../core/ansi_term.js').setSyncTermFontWithAlias;
// deps
const async = require('async');
const _ = require('lodash');
const net = require('net');
const EventEmitter = require('events');
const buffers = require('buffers');
/*
Expected configuration block:
{
module: telnet_bridge
...
config: {
host: somehost.net
port: 23
}
}
*/
// :TODO: ENH: Support nodeMax and tooManyArt
exports.getModule = TelnetBridgeModule;
exports.moduleInfo = {
name : 'Telnet Bridge',
desc : 'Connect to other Telnet Systems',
author : 'Andrew Pamment',
};
const IAC_DO_TERM_TYPE = new Buffer( [ 255, 253, 24 ] );
class TelnetClientConnection extends EventEmitter {
constructor(client) {
super();
this.client = client;
}
restorePipe() {
if(!this.pipeRestored) {
this.pipeRestored = true;
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// client may have bailed
if(_.has(this, 'client.term.output')) {
this.client.term.output.unpipe(this.bridgeConnection);
this.client.term.output.resume();
}
}
}
connect(connectOpts) {
this.bridgeConnection = net.createConnection(connectOpts, () => {
this.emit('connected');
this.pipeRestored = false;
this.client.term.output.pipe(this.bridgeConnection);
});
this.bridgeConnection.on('data', data => {
this.client.term.rawWrite(data);
//
// Wait for a terminal type request, and send it eactly once.
// This is enough (in additional to other negotiations handled in telnet.js)
// to get us in on most systems
//
if(!this.termSent && data.indexOf(IAC_DO_TERM_TYPE) > -1) {
this.termSent = true;
this.bridgeConnection.write(this.getTermTypeNegotiationBuffer());
}
});
this.bridgeConnection.once('end', () => {
this.restorePipe();
this.emit('end');
});
this.bridgeConnection.once('error', err => {
this.restorePipe();
this.emit('end', err);
});
}
disconnect() {
if(this.bridgeConnection) {
this.bridgeConnection.end();
}
}
getTermTypeNegotiationBuffer() {
//
// Create a TERMINAL-TYPE sub negotiation buffer using the
// actual/current terminal type.
//
let bufs = buffers();
bufs.push(new Buffer(
[
255, // IAC
250, // SB
24, // TERMINAL-TYPE
0, // IS
]
));
bufs.push(
new Buffer(this.client.term.termType), // e.g. "ansi"
new Buffer( [ 255, 240 ] ) // IAC, SE
);
return bufs.toBuffer();
}
}
function TelnetBridgeModule(options) {
MenuModule.call(this, options);
const self = this;
this.config = options.menuConfig.config;
// defaults
this.config.port = this.config.port || 23;
this.initSequence = function() {
let clientTerminated;
async.series(
[
function validateConfig(callback) {
if(_.isString(self.config.host) &&
_.isNumber(self.config.port))
{
callback(null);
} else {
callback(new Error('Configuration is missing required option(s)'));
}
},
function createTelnetBridge(callback) {
const connectOpts = {
port : self.config.port,
host : self.config.host,
};
let clientTerminated;
self.client.term.write(resetScreen());
self.client.term.write(` Connecting to ${connectOpts.host}, please wait...\n`);
const telnetConnection = new TelnetClientConnection(self.client);
telnetConnection.on('connected', () => {
self.client.log.info(connectOpts, 'Telnet bridge connection established');
if(self.config.font) {
self.client.term.rawWrite(setSyncTermFontWithAlias(self.config.font));
}
self.client.once('end', () => {
self.client.log.info('Connection ended. Terminating connection');
clientTerminated = true;
telnetConnection.disconnect();
});
});
telnetConnection.on('end', err => {
if(err) {
self.client.log.info(`Telnet bridge connection error: ${err.message}`);
}
callback(clientTerminated ? new Error('Client connection terminated') : null);
});
telnetConnection.connect(connectOpts);
}
],
err => {
if(err) {
self.client.log.warn( { error : err.message }, 'Telnet connection error');
}
if(!clientTerminated) {
self.prevMenu();
}
}
);
};
}
require('util').inherits(TelnetBridgeModule, MenuModule);