connection.js

'use strict';
const debug = require('debug')('pop3-connection');
const TEN_MINUTES = 10 * 60 * 1000;
const States = require('./states');

var POP3Connnection = module.exports = function(server, socket, connection_id) {
  debug('connection ' + connection_id, socket.remoteAddress);
  var self = this;
  this.socket = socket;
  this.server = server;
  this.connection_id = connection_id;
  this.state = States.AUTHENTICATION;
  this.UID = this.connection_id + "." + (+new Date());
  this.response("+OK POP3 Server ready <" + self.UID + "@" + self.server_name + ">");
};

POP3Connnection.prototype.response = function response(message) {
  let resBuffer;
  if (message.toString) {
    message = message.toString();
  }
  if (typeof message == "string") {
    debug('responding', this.user, message.substring(0, 60));
    resBuffer = new Buffer(message + "\r\n", "utf-8");
  } else {
    resBuffer = Buffer.concat([message, new Buffer("\r\n", "utf-8")]);
  }

  this.socket.write(resBuffer);
};

/**
 * POP3Server#destroy() -> undefined
 *
 * Clears the used variables just in case (garbage collector should
 * do this by itself)
 **/
POP3Connnection.prototype.destroy = function destroy() {
  const remoteAddress = this.socket ? this.socket.remoteAddress : null;
  debug('destroying connection', this.user, this.connection_id, remoteAddress);

  if (this.timer) {
    clearTimeout(this.timer);
  }
  this.timer = null;

  if (this.server.connected_users[this.user]) {
    delete this.server.connected_users[this.user];
  }

  if (this.socket && this.socket.end) {
    this.socket.end();
  }
};

// kill client after inactivity
POP3Connnection.prototype.updateTimeout = function() {
  if (this.timer) clearTimeout(this.timer);
  this.timer = setTimeout((function() {
    if (!this.socket)
      return;
    if (this.state == States.TRANSACTION) {
      this.state = States.UPDATE;
    }
    debug("Connection closed for client inactivity", this.user);
    this.destroy();
  }).bind(this), TEN_MINUTES);
};