Ssh-chat, part 2

Hello, Habr. This is the second article in the ssh-chat series.

What we will do:

• Add the ability to create custom formatting functions.
• Add markdown support.
• Add bot support.
• Enhance password security (hash and salt).
  Unfortunately, file sending will not be available.

Custom formatting functions.

Currently, the following formatting functions are supported:

• @color
• @bold
• @underline
• @hex
• @box
  But we should add the ability to create custom functions:
  All functions are stored in an object called methods.
  So it's enough to create a function registerMethod.:

// parserExec.js at end
module.exports.registerMethod  =  function(name, func) {
  methods[name] =  func
}

This method also needs to be returned after creating the server.

// index.js at require part
const { registerMethod } = require('./parserExec')

// index.js at end
module.exports.registerMethod  =  registerMethod

Now when creating the server, we can register formatting methods. Example:

const chat = require('.')
const { formatNick } = require('./format')

chat({})

chat.registerMethod('hello', function(p, name){
  return 'Hi, ' + formatNick(name) + '!'
})

Markdown support.

Markdown is very convenient, so we'll add it with marked terminal.

// format.js near require
const marked = require('marked');
const TerminalRenderer = require('marked-terminal');

marked.setOptions({
  renderer: new TerminalRenderer()
});

// format.js line 23
message = marked(message)

Bots.

How it will work.

let writeBotBob = chat.registerBot({
  name: 'botBob',

  onConnect(nick, write){
    write('@hello{' + nick + '}')
  },

  onDisconnect(nick, write){},

  onMessage(nick, message, write) {
    if(message == 'botBob!') write('I'm here')
  },

  onCommand(command, write) {
    write('Doing ' + command)
  }
})

onCommand can be called using @bot(botBob){Command}

Everything for working with bots is described in the file:

let bots = []; // Все боты

let onWrite = () => {}; 

function getWrite(bot) { // Генерирует метод отправки сообщения для бота
  return msg => {
    onWrite(bot.name, msg);
  };
}

module.exports.message = function message(nick, message) { // index.js выполнит эту функцию после отправки сообщения
  bots.forEach(bot => {
    try {
      bot.onMessage(nick, message, getWrite(bot));
    } catch (e) {
      console.error(e);
    }
  });
};

module.exports.connect = function message(nick) { // При соединении
  bots.forEach(bot => {
    try {
      bot.onConnect(nick, getWrite(bot));
    } catch (e) {
      console.error(e);
    }
  });
};

module.exports.disConnect = function message(nick) { // При отсоединении
  bots.forEach(bot => {
    try {
      bot.onDisconnect(nick, message, getWrite(bot));
    } catch (e) {
      console.error(e);
    }
  });
};

module.exports.command = function message(name, message) { // При выполнении команды
  bots.forEach(bot => {
    if (bot.name == name) {
      try {
        bot.onCommand(message, getWrite(bot));
      } catch (e) {
        console.error(e);
      }
    }
  });
};

module.exports.registerBot = function(bot) {
  bots.push(bot);
  return  getWrite(bot)
};

module.exports.onMessage = func => {
  onWrite = func;
};

What can be done with bots:

• Load monitoring.
• Deploy
• Task board.

Hash and salt.

Why not ssh keys? Because ssh keys will differ on different devices.
Let's create a file that will be responsible for checking and creating passwords.

// crypto.js
const crypto = require('crypto');

function genRandomString(length) {
  return crypto
    .randomBytes(Math.ceil(length / 2))
    .toString('hex')
    .slice(0, length);
}

function sha512(password, salt){
  const hash = crypto.createHmac('sha512', salt); /** Hashing algorithm sha512 */
  hash.update(password);
  const value = hash.digest('hex');
  return value
};

function checkPass(pass, obj){
  return obj.password == sha512(pass, obj.salt)
}

function encodePass(pass){
  const salt = genRandomString(16)
  return JSON.stringify({
    salt,
    password: sha512(pass, salt)
  })
}

module.exports.encodePass = encodePass
module.exports.checkPass = checkPass

Also, a script for salting and hashing the password.

// To generate password run node ./encryptPassword password
const { encodePass } =require('./crypto')
console.log(encodePass(process.argv[2]))

Update in users.json and instead of comparison in lobby.js, use checkPassword.

Summary

As a result, we have an ssh chat with formatting capabilities and bots.
Final repository.

Source: habr.com