#!/usr/bin/python
#
# Python module to mass validating email address
#
# This module was inspired by (and use) validate_email library
# write by Syrus Akbary :
# 
#    https://github.com/SyrusAkbary/validate_email
#
# This main goal is to optimize mass validating using cache of
# bad (or good) domain or MX server.
#
# Author: Benjamin Renard
# Website: http://git.zionetrix.net/mass_validate_email
# Licence: LGPL

import sys
import logging

from validate_email import validate_email
import smtplib
import socket
import DNS

try:
	DNS.DiscoverNameServers()
except DNS.ServerError, e:
	logging.fatal("Error discovering DNS servers : %s" % e)
	sys.exit(1)

# options
class OptionsClass(object):

	def __init__(self):
		self.debug = False
		self.debugsmtp = False
		self.checkmx = False
		self.verifyaddress = False
		self.usesmtpvrfy = False
		self.refusemailifnotpermit = True
		self.refuseontemporaryerror = True

options=OptionsClass()

if options.verifyaddress:
	options.checkmx=True

def clean_mail(mail):
	mail=str(mail).lower().strip()
	return mail


domain_mx={}
valid_domain=[]
invalid_domain=[]
def check_mx(mail):
	dom = mail[mail.find('@')+1:]
	if not options.verifyaddress:
		if dom in valid_domain:
			return True
		elif dom in invalid_domain:
			return False
		else:
			try:
				mx_hosts = DNS.mxlookup(dom)
				if len(mx_hosts)>0:
					domain_mx[dom]=[]
					for mx in mx_hosts:
						domain_mx[dom].append(mx[1])
					logging.debug("MX of domain %s : %s" % (dom,','.join(domain_mx[dom])))
					valid_domain.append(dom)
					return True
				elif connect_to_mx(dom):
					domain_mx[dom]=[dom]
					logging.debug("MX of domain %s : %s" % (dom,','.join(domain_mx[dom])))
					valid_domain.append(dom)
					return True
				else:
					logging.debug("No valid MX of domain %s found" % dom)
					invalid_domain.append(dom)
					return False
			except DNS.ServerError, e:
				logging.debug('Error getting MX servers of domain %s : %s' % (dom,e))
				invalid_domain.append(dom)
				return False
	else:
		if dom in invalid_domain:
			return False
		if dom in domain_mx:
			for mx in domain_mx[dom]:
				con = connect_to_mx(mx)
				if not con:
					continue
				if check_mail_on_mx(dom,con,mail,ifNotPermit=(not options.refusemailifnotpermit)):
					return True
			return False
		else:
			try:
				mx_hosts = DNS.mxlookup(dom)
				if len(mx_hosts)>0:
					domain_mx[dom]=[]
					for mx in mx_hosts:
						domain_mx[dom].append(mx[1])
					valid_domain.append(dom)
					return check_mx(mail)
				else:
					# Directly check MX and mail
					con=connect_to_mx(dom)
					if not con:
						invalid_domain.append(dom)
						return False
					domain_mx[dom]=[dom]
					return check_mail_on_mx(dom,con,mail,ifNotPermit=(not options.refusemailifnotpermit))
			except DNS.ServerError, e:
				logging.debug('Error getting MX servers of domain %s : %s' % (dom,e))
				invalid_domain.append(dom)
				return False

valid_mx=[]
invalid_mx=[]
def verify_mx(mx,mail,check_mail=False):
	if not check_mail and mx in valid_mx:
		return True
	elif not check_mail and mx in invalid_mx:
		return False

def connect_to_mx(mx):
	if mx in invalid_mx:
		return False
	try:
		smtp = smtplib.SMTP(timeout=5)
		smtp.connect(mx)
		if options.debugsmtp:
			smtp.set_debuglevel(True)
		valid_mx.append(mx)
		return smtp
	except smtplib.SMTPConnectError:
		logging.debug("MX server %s does not respond from SMTP" % mx)
	except smtplib.SMTPServerDisconnected:
		logging.debug("MX server %s unexpectedly closed connection" % mx)
	except socket.gaierror:
		logging.debug("Can't resolv MX server %s" % mx)
	except socket.timeout:
		logging.debug("Connection timeout to SMTP server %s" % mx)
	except socket.error:
		logging.debug("Connection error on SMTP server %s" % mx)
	except Exception, e:
		logging.error("Unknown error (%s) connecting to SMTP server %s : %s" % (type(e),mx,e))
	invalid_mx.append(mx)
	return None

mx_refuse_check_mail=[]
def check_mail_on_mx(mx,smtp,mail,ifNotPermit=False):
	if mx in mx_refuse_check_mail:
		return ifNotPermit
	try:
		status, _ = smtp.helo()
		if status != 250:
			mx_refuse_check_mail.append(mx)
			return ifNotPermit

		if options.usesmtpvrfy:
			(status, msg) = smtp.verify(mail)
			if status >= 250 and status < 260:
				# Server normaly return an normalize email address
				for word in msg.split(' '):
					if validate_email(word):
						return True
		smtp.mail('')
		status, msg = smtp.rcpt(mail)
		if status >= 400 and status < 500:
			logging.debug('SMTP server return temporary error (code=%s) : %s' % (status,msg))
			return not options.refuseontemporaryerror
		elif status != 250:
			return False
		return True
	except smtplib.SMTPServerDisconnected:
		# Server not permits verify user
		mx_refuse_check_mail.append(mx)
		return ifNotPermit
	except smtplib.SMTPConnectError:
		return False

def mass_validate_email(mail,simple=False):
	mail=clean_mail(mail)
	if not validate_email(mail):
		return
	elif simple:
		return True
	elif options.checkmx:
		return check_mx(mail)
	else:
		return True

if __name__=='__main__':

	if len(sys.argv)!=2:
		print "Usage : %s [email]" % sys.argv[0]
		sys.exit(0)

	logging.basicConfig(level=logging.DEBUG)
	options.debugsmtp=True

	mail=sys.argv[1]

	print "Simple syntax validation :"
	print "=========================="
	print "Return : %s" % mass_validate_email(mail)

	options.checkmx=True
	print "\n\n"
	print "Syntax validation and domain MX check :"
	print "======================================="
	print "Return : %s" % mass_validate_email(mail)

	options.verifyaddress=True
	print "\n\n"
	print "Syntax validation, domain MX check and validation of email address by SMTP server :"
	print "==================================================================================="
	print "Return : %s" % mass_validate_email(mail)