gistfile1.js

var net = require('net');
var extend = require('node.extend');

function Session(lime){
  this.lime = lime;

	this.store = {};

	this.mode = 0;
	// 0 - expecting helo/ehlo
	// 1 - expecting mail
	// 2 - expecting rcpt
	// 3 - expecting data (or more rcpt)
	// 4 - data (expecting .)

	this.from = '';
	this.to = [];
	this.body = '';

	this.c = null;

	var t = this;

	this.listen = function(){
		t.c.on('data', function(data){
			var line = data.toString().trim();
			var parts = line.split(' ');
			var remainder = parts.slice(1).join(' ');
			if(4 > t.mode) {
				var command = parts[0].toLowerCase();
				if(t.commands[command])
					t.commands[command](remainder);
				else
					t.unknown(line);
			} else {
				t.body += data;
				if(data.toString().match(/(^|\n)\.(\r?\n)?$/)){
					t.body = t.body.replace(/\r?\n\.\r?\n$/,'');
					t.lime.trigger('data_post',function(response){
						if(2 === response){
							t.c.write('554 I didn\'t like your message, so it wasn\'t saved\r\n');
						} else {
							t.mode = 1;
							t.c.write('250 OK I haz all your data, now whatcha gonna do?\r\n');
						}
					},t,[t.from,t.to,t.body]);
				}
			}
		});
	}

	this.commands = {
		helo: function(remainder){
			t.lime.trigger('helo',function(response){
				if(2 === response)
					t.c.end();
				else {
					t.mode = 1;
					t.c.write('250 limebin.com Hello, you look nice today!\r\n');
				}
			},t);
		},

		ehlo: function(remainder){
			t.lime.trigger('helo',function(response){
				if(2 === response)
					t.c.end();
				else {
					t.mode = 1;
					t.c.write('250-limebin.com Hello, you look nice today!\r\n');
					t.c.write('250 size 10485760\r\n');
				}
			},t);
		}, 

		mail: function(remainder){
			var matches;
			var from = '';
			if(!(matches=remainder.match(/^from:\s?<?(.*?)>?\s?$/i))){
				t.lime.trigger('invalid',function(response){
					if(2 === response)
						t.c.end();
					else
						t.c.write('501 Check your syntax, bro!\r\n');
				},t);
				return;
			}
			from = matches[1].trim();
			if(0==t.mode){
				t.lime.trigger('invalid',function(response){
					if(2 === response)
						t.c.end();
					else
						t.c.write('503 That\'s a little rude, you should say HELO first!\r\n');
				},t);
				return;
			}

			t.lime.trigger('mail',function(response){
				if(2 === response){
					t.c.write('451 We do not accept mail from that address.\r\n');
				} else {
					t.mode = 2;
					t.to = [];
					t.from = from;
					t.c.write('250 OK Now why don\'t you tell me where to send it?\r\n');
				}
			},t,from);
		},

		rcpt: function(remainder){
			var matches;
			var to = '';
			if(!(matches=remainder.match(/^to:\s?<?(.*?)>?\s?$/i))){
				t.lime.trigger('invalid',function(response){
					if(2 === response)
						t.c.end();
					else
						t.c.write('501 Check your syntax, bro!\r\n');
				},t);
				return;
			}
			to = matches[1].trim();

			if(0==t.mode){
				t.lime.trigger('invalid',function(response){
					if(2 === response)
						t.c.end();
					else
						t.c.write('503 That\'s a little rude, you should say HELO first!\r\n');
				},t);
				return;
			} else if(1==t.mode){
				t.lime.trigger('invalid',function(response){
					if(2 === response)
						t.c.end();
					else
						t.c.write('503 WHOA BUDDY, YOU ARE GETTING AHEAD OF YOURSELF, MAIL FIRST!\r\n');
				},t);
				return;
			}

			t.lime.trigger('rcpt',function(response){
				if(2 === response){
					t.c.write('550 WHO DAT?\r\n');
				} else if(1 === response) {
					t.mode = 3;
					t.to.push(to);
					t.c.write('250 OK Got it, now what?\r\n');
				} else {
					t.c.write('550 WHO DAT?\r\n');
				}
			},t,to);
		},

		data: function(remainder){
			if(0==t.mode){
				t.lime.trigger('invalid',function(response){
					if(2 === response)
						t.c.end();
					else
						t.c.write('503 That\'s a little rude, you should say HELO first!\r\n');
				},t);
				return;
			} else if(1==t.mode){
				t.lime.trigger('invalid',function(response){
					if(2 === response)
						t.c.end();
					else
						t.c.write('503 WHOA BUDDY, YOU ARE GETTING AHEAD OF YOURSELF, MAIL FIRST!\r\n');
				},t);
				return;
			} else if(2==t.mode){
				t.lime.trigger('invalid',function(response){
					if(2 === response)
						t.c.end();
					else
						t.c.write('503 Now who do you expect me to deliver this to?  RCPT FIRST!\r\n');
				},t);
				return;
			}

			t.lime.trigger('data',function(response){
				if(2 === response){
					t.c.end();
				} else {
					t.mode = 4;
					t.c.write('354 Go ahead, give me your tired, your poor, your huddled data yearning to breathe free.\r\n');
				}
			},t);
		},

		quit: function(remainder){
			t.lime.trigger('helo',function(response){
				if(2 === response)
					t.c.end();
				else {
					t.c.write('221 Leaving me already?  I\'ll miss you, visit again soon!\r\n');
					t.c.end();
				}
			},t);
		}
	}

	this.unknown = function(line){
		t.lime.trigger('unknown',function(response){
			if(2 === response)
				t.c.end()
			else
				t.c.write('502 SAY WHAT?\r\n');
		},t);
	}
}

Session.prototype.start = function(c){
	var t = this;
	this.c=c;
	this.lime.trigger('connect',function(response){
		if(2 === response)
			c.end();
		else {
			c.write('220 limebin.com ESMTP Welcome to the best mail server EVAR!!!1!!one!!eleven!!!11!\r\n');
			t.listen();
		}
	},t);
}

function Lime(){
	this.callbacks = {
		'connect':[],
		'helo':[],
		'mail':[],
		'rcpt':[],
		'data':[],
		'data_post':[],
		'quit':[],
		'unknown':[],
		'invalid':[]
	};
}

Lime.prototype.start = function(){
	var lime = this;
	var server = net.createServer(function(c) {
		var s = new Session(lime);
		s.start(c);
	});

	server.listen(25);
}

Lime.prototype.on = function(event, callback){
	if(this.callbacks[event])
		this.callbacks[event].push(callback);
}

Lime.prototype.trigger = function(event, callback, con, data, callbacks){
	if(!this.callbacks[event] || !this.callbacks[event].length){
		return callback(0);
	}
	if(!callbacks){
		callbacks = extend([],this.callbacks[event]);
	} else if(!callbacks.length) {
		return callback(0);
	}

	var cb = callbacks.shift();
	var t = this;

	var timeoutTimer = setTimeout(function(){
		callbacks = [];
		callback(2);
	},5000);

	var next = function(resp, message){
		timeoutFunction = function(){}
		clearTimeout(timeoutTimer);
		
		if(resp && (1===resp || 2===resp))
			return callback(resp, message);
		
		t.trigger(event,callback,con,data,callbacks);
	}
	if(cb)
		cb(next,con,data);
}

exports.CONT = 0;
exports.OK = 1;
exports.DENY = 2;
exports.server = Lime;