main.py

import re
import smtplib
import dns.resolver
import pandas as pd
from tkinter import Tk
from tkinter.filedialog import askopenfilename, asksaveasfilename

def main():
	print("Program: Email Ping")
	print("Release: 1.0")
	print("Date: 2019-05-31")
	print("Author: Brian Neely")
	print()
	print()
	print("This program pings a email web server for a specified email address in a csv.")
	print("It assumes that the csv file is encoded in UTF-8 and is comma delimited.")
	print("A significant portion of the ping_email function is copied from the work of Scott Brady from his Python-Email-Verification-Script")
	print("His work and this work is licensed under the Apache License 2.0")
	print()
	print()

	print("Program Starting")
	# Hide Tkinter GUI
	Tk().withdraw()

	# Find input file
	print("Select File in")
	file_in = askopenfilename(initialdir="../", title="Select input file",
							  filetypes=(("Comma Separated Values", "*.csv"), ("all files", "*.*")))
	if not file_in:
		input("Program Terminated. Press Enter to continue...")
		exit()

	# Set ouput file
	file_out = asksaveasfilename(initialdir=file_in, title="Select output file",
								 filetypes=(("Comma Separated Values", "*.csv"), ("all files", "*.*")))
	if not file_out:
		input("Program Terminated. Press Enter to continue...")
		exit()

	# Read csv
	data = pd.read_csv(file_in, low_memory=False)

	# Find email column
	email_col = column_selection(list(data))

	# Test each email address
	for i in data[email_col]:
		print('')
		print(i)
		# data["Email Validity"] = ping_email(i)
		try:
			data.loc[data[email_col] == i, "Email Validity"] = ping_email(i)
		except:
			data.loc[data[email_col] == i, "Email Validity"] = "Domain Doesn't Exist"

	# Write CSV
	print("Writing CSV File...")
	data.to_csv(file_out, index=False)
	print("Wrote CSV File!")
	print()

	print("File written to: " + file_out)
	input("Press Enter to close...")


def ping_email(inputAddress):
	# Print what email is being tested
	# print("Testing: " + inputAddress)

	# Address used for SMTP MAIL FROM command
	fromAddress = 'noresponse@gmail.com'

	# Simple Regex for syntax checking
	regex = '^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,})$'

	# Email address to verify
	addressToVerify = str(inputAddress)

	# Lower case address
	addressToVerify = addressToVerify.lower()

	# Syntax check
	match = re.match(regex, addressToVerify)
	if match == None:
		return 'Bad Syntax'

	# Get domain for DNS lookup
	splitAddress = addressToVerify.split('@')
	domain = str(splitAddress[1])
	# print('Domain:', domain)

	# MX record lookup
	records = dns.resolver.query(domain, 'MX')
	mxRecord = records[0].exchange
	mxRecord = str(mxRecord)

	# SMTP lib setup (use debug level for full output)
	server = smtplib.SMTP()
	server.set_debuglevel(0)

	# SMTP Conversation
	server.connect(mxRecord)
	server.helo(server.local_hostname) ### server.local_hostname(Get local server hostname)
	server.mail(fromAddress)
	code, message = server.rcpt(str(addressToVerify))
	server.quit()

	#print(code)
	#print(message)

	# Assume SMTP response 250 is success
	if code == 250:
		return 'Success'
	else:
		return 'Failed'


def column_selection(headers):
	while True:
		try:
			print("Select column.")
			for j, i in enumerate(headers):
				print(str(j) + ": to perform sentiment analysis on column [" + str(i) + "]")
			column = headers[int(input("Enter Selection: "))]
		except ValueError:
			print("Input must be integer between 0 and " + str(len(headers)))
			continue
		else:
			break
	return column


if __name__ == '__main__':
	main()