service-validate-mail.py

#!/usr/bin/python3
# -*- coding: utf-8 -*-
#=============================================================
# Created: Tue 30 Nov 2021 10:47:14 PM -03
#=============================================================
# Description: API that checks if the email is valid.
# Autor: Leonardo Berbert Gomes

from flask import Flask
from flask import request
from flask import jsonify
from flask_restful import Resource, Api
from os import path
import json,re,sys,os
from email_validator import validate_email, EmailNotValidError

if path.exists('blacklist.conf') == False:
    print('\nIs not possible to start application without blacklist file \'blacklist.conf\'!!!\n')
    sys.exit(0)

config = open("blacklist.conf","r").read().splitlines()
pattern = '.*|.*'.join(config)

cli = sys.modules['flask.cli']
cli.show_server_banner = lambda *x: None

app = Flask(__name__)
api = Api(app)

class Mail(Resource):
    def post(self):
        data = json.loads(request.data)
        emailAddress = data['emailAddress']
        blacklist = re.match(pattern,emailAddress,re.IGNORECASE)
        if blacklist:
                return jsonify({
                    "emailAddress": str(emailAddress), 
                    "status": 2,
                    "bounce": { 
                    "type": 1, 
                    "detail": "Bad destination mailbox address", 
                    "code": 511
                    }
                })     
    
        if emailAddress:
            isValidate = ValidateMail(emailAddress)
            if isValidate == "1": # valid email
                return jsonify({
                                "emailAddress": str(emailAddress), 
                                "status": 1
                            })            
            else:
                return jsonify({
                    "emailAddress": str(emailAddress), 
                    "status": 2,
                    "bounce": { 
                    "type": 1, 
                    "detail": "Invalid mail format", 
                    "code": 990
                    }
                })
                
class Health(Resource):
    def get(self):
        response = "OK"
        return response
        
def ValidateMail(email):
    try:
        valid = validate_email(email)
        email = valid.email

        if email:
            return('1')
        else:
            return('0')
    except EmailNotValidError as e:
        print(str(e))

api.add_resource(Mail, '/api/v1/',methods = ['POST']) 
api.add_resource(Health, '/health',methods = ['GET'])

if __name__ == '__main__': 
    app.run(host='0.0.0.0')