PowerDNS-Admin/app/models.py

import os
import ldap
import ldap.filter
import time
import base64
import bcrypt
import itertools
import traceback
import pyotp
import re
import dns.reversename
import sys
import logging as logger

from datetime import datetime
from urllib.parse import urljoin
from distutils.util import strtobool
from distutils.version import StrictVersion
from flask_login import AnonymousUserMixin

from app import app, db
from app.lib import utils

logging = logger.getLogger(__name__)

if 'LDAP_TYPE' in app.config.keys():
    LDAP_URI = app.config['LDAP_URI']

    if 'LDAP_USERNAME' in app.config.keys() and 'LDAP_PASSWORD' in app.config.keys(): #backward compatability
        LDAP_BIND_TYPE = 'search'
    if 'LDAP_BIND_TYPE' in app.config.keys():
        LDAP_BIND_TYPE = app.config['LDAP_BIND_TYPE']
    if LDAP_BIND_TYPE == 'search':
        LDAP_USERNAME = app.config['LDAP_USERNAME']
        LDAP_PASSWORD = app.config['LDAP_PASSWORD']

    LDAP_SEARCH_BASE = app.config['LDAP_SEARCH_BASE']
    LDAP_TYPE = app.config['LDAP_TYPE']
    LDAP_FILTER = app.config['LDAP_FILTER']
    LDAP_USERNAMEFIELD = app.config['LDAP_USERNAMEFIELD']

    LDAP_GROUP_SECURITY = app.config.get('LDAP_GROUP_SECURITY')
    if LDAP_GROUP_SECURITY == True:
        LDAP_ADMIN_GROUP = app.config['LDAP_ADMIN_GROUP']
        LDAP_USER_GROUP = app.config['LDAP_USER_GROUP']
else:
    LDAP_TYPE = False

if 'PRETTY_IPV6_PTR' in app.config.keys():
    import dns.inet
    import dns.name
    PRETTY_IPV6_PTR = app.config['PRETTY_IPV6_PTR']
else:
    PRETTY_IPV6_PTR = False

PDNS_STATS_URL = app.config['PDNS_STATS_URL']
PDNS_API_KEY = app.config['PDNS_API_KEY']
PDNS_VERSION = app.config['PDNS_VERSION']
API_EXTENDED_URL = utils.pdns_api_extended_uri(PDNS_VERSION)

# Flag for pdns v4.x.x
# TODO: Find another way to do this
if StrictVersion(PDNS_VERSION) >= StrictVersion('4.0.0'):
    NEW_SCHEMA = True
else:
    NEW_SCHEMA = False

class Anonymous(AnonymousUserMixin):
  def __init__(self):
    self.username = 'Anonymous'


class User(db.Model):

    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(64), index=True, unique=True)
    password = db.Column(db.String(64))
    firstname = db.Column(db.String(64))
    lastname = db.Column(db.String(64))
    email = db.Column(db.String(128))
    avatar = db.Column(db.String(128))
    otp_secret = db.Column(db.String(16))
    role_id = db.Column(db.Integer, db.ForeignKey('role.id'))

    def __init__(self, id=None, username=None, password=None, plain_text_password=None, firstname=None, lastname=None, role_id=None, email=None, avatar=None, otp_secret=None, reload_info=True):
        self.id = id
        self.username = username
        self.password = password
        self.plain_text_password = plain_text_password
        self.firstname = firstname
        self.lastname = lastname
        self.role_id = role_id
        self.email = email
        self.avatar = avatar
        self.otp_secret = otp_secret

        if reload_info:
            user_info = self.get_user_info_by_id() if id else self.get_user_info_by_username()

            if user_info:
                self.id = user_info.id
                self.username = user_info.username
                self.firstname = user_info.firstname
                self.lastname = user_info.lastname
                self.email = user_info.email
                self.role_id = user_info.role_id
                self.otp_secret = user_info.otp_secret

    def is_authenticated(self):
        return True

    def is_active(self):
        return True

    def is_anonymous(self):
        return False

    def get_id(self):
        try:
            return unicode(self.id)  # python 2
        except NameError:
            return str(self.id)  # python 3

    def __repr__(self):
        return '<User {0}>'.format(self.username)

    def get_totp_uri(self):
        return "otpauth://totp/PowerDNS-Admin:{0}?secret={1}&issuer=PowerDNS-Admin".format(self.username, self.otp_secret)

    def verify_totp(self, token):
        totp = pyotp.TOTP(self.otp_secret)
        return totp.verify(int(token))

    def get_hashed_password(self, plain_text_password=None):
        # Hash a password for the first time
        #   (Using bcrypt, the salt is saved into the hash itself)
        if plain_text_password == None:
            return plain_text_password

        pw = plain_text_password if plain_text_password else self.plain_text_password
        return bcrypt.hashpw(pw.encode('utf-8'), bcrypt.gensalt())

    def check_password(self, hashed_password):
        # Check hased password. Useing bcrypt, the salt is saved into the hash itself
        if (self.plain_text_password):
            return bcrypt.checkpw(self.plain_text_password.encode('utf-8'), hashed_password.encode('utf-8'))
        return False

    def get_user_info_by_id(self):
        user_info = User.query.get(int(self.id))
        return user_info

    def get_user_info_by_username(self):
        user_info = User.query.filter(User.username == self.username).first()
        return user_info

    def ldap_search(self, searchFilter, baseDN):
        searchScope = ldap.SCOPE_SUBTREE
        retrieveAttributes = None

        try:
            ldap.set_option(ldap.OPT_X_TLS_REQUIRE_CERT, ldap.OPT_X_TLS_NEVER)
            l = ldap.initialize(LDAP_URI)
            l.set_option(ldap.OPT_REFERRALS, ldap.OPT_OFF)
            l.set_option(ldap.OPT_PROTOCOL_VERSION, 3)
            l.set_option(ldap.OPT_X_TLS,ldap.OPT_X_TLS_DEMAND)
            l.set_option( ldap.OPT_X_TLS_DEMAND, True )
            l.set_option( ldap.OPT_DEBUG_LEVEL, 255 )
            l.protocol_version = ldap.VERSION3
            if LDAP_BIND_TYPE == "direct":
                global LDAP_USERNAME; LDAP_USERNAME = self.username
                global LDAP_PASSWORD; LDAP_PASSWORD = self.password


            l.simple_bind_s(LDAP_USERNAME, LDAP_PASSWORD)
            ldap_result_id = l.search(baseDN, searchScope, searchFilter, retrieveAttributes)
            result_set = []
            while 1:
                result_type, result_data = l.result(ldap_result_id, 0)
                if (result_data == []):
                    break
                else:
                    if result_type == ldap.RES_SEARCH_ENTRY:
                        result_set.append(result_data)
            return result_set

        except ldap.LDAPError as e:
            logging.error(e)
            raise

    def is_validate(self, method):
        """
        Validate user credential
        """
        if method == 'LOCAL':
            user_info = User.query.filter(User.username == self.username).first()

            if user_info:
                if user_info.password and self.check_password(user_info.password):
                    logging.info('User "{0}" logged in successfully'.format(self.username))
                    return True
                logging.error('User "{0}" input a wrong password'.format(self.username))
                return False

            logging.warning('User "{0}" does not exist'.format(self.username))
            return False

        if method == 'LDAP':
            allowedlogin = False
            isadmin = False
            if not LDAP_TYPE:
                logging.error('LDAP authentication is disabled')
                return False

            if LDAP_TYPE == 'ldap':
                searchFilter = "(&({0}={1}){2})".format(LDAP_USERNAMEFIELD, self.username, LDAP_FILTER)
                logging.info('Ldap searchFilter "{0}"'.format(searchFilter))
            elif LDAP_TYPE == 'ad':
                searchFilter = "(&(objectcategory=person)({0}={1}){2})".format(LDAP_USERNAMEFIELD, self.username, LDAP_FILTER)

            result = self.ldap_search(searchFilter, LDAP_SEARCH_BASE)
            if not result:
                logging.warning('LDAP User "{0}" does not exist'.format(self.username))
                return False

            try:
                ldap_username = ldap.filter.escape_filter_chars(result[0][0][0])
                if LDAP_GROUP_SECURITY:
                    try:
                        if LDAP_TYPE == 'ldap':
                            ldap_user_dn = ldap.filter.escape_filter_chars(result[0][0][0])
                            logging.info(result[0][0][0])
                        if (self.ldap_search('(member={0})'.format(ldap_user_dn) ,LDAP_ADMIN_GROUP)):
                            allowedlogin = True
                            isadmin = True
                            logging.info('User {0} is part of the "{1}" group that allows admin access to PowerDNS-Admin'.format(self.username,LDAP_ADMIN_GROUP))
                        if (self.ldap_search('(member={0})'.format(ldap_user_dn) ,LDAP_USER_GROUP)):
                            #if (group == LDAP_USER_GROUP):
                            allowedlogin = True
                            logging.info('User {0} is part of the "{1}" group that allows user access to PowerDNS-Admin'.format(self.username,LDAP_USER_GROUP))
                        if allowedlogin == False:
                            logging.error('User {0} is not part of the "{1}" or "{2}" groups that allow access to PowerDNS-Admin'.format(self.username,LDAP_ADMIN_GROUP,LDAP_USER_GROUP))
                            return False
                    except Exception as e:
                        logging.error('LDAP group lookup for user "{0}" has failed'.format(e))
                        return False
                    logging.info('User "{0}" logged in successfully'.format(self.username))
            except Exception as e:
                logging.error('User "{0}" input a wrong LDAP password'.format(e))
                return False

            # create user if not exist in the db
            if not User.query.filter(User.username == self.username).first():
                self.firstname = self.username
                self.lastname = ''
                try:
                    # try to get user's firstname & lastname from LDAP
                    # this might be changed in the future
                    self.firstname = result[0][0][1]['givenName']
                    self.lastname = result[0][0][1]['sn']
                    self.email = result[0][0][1]['mail']
                except Exception as e:
                    logging.info("reading ldap data threw an exception {0}".format(e))

                # first register user will be in Administrator role
                self.role_id = Role.query.filter_by(name='User').first().id
                if User.query.count() == 0:
                    self.role_id = Role.query.filter_by(name='Administrator').first().id

                # user will be in Administrator role if part of LDAP Admin group
                if LDAP_GROUP_SECURITY:
                    if isadmin == True:
                        self.role_id = Role.query.filter_by(name='Administrator').first().id

                self.create_user()
                logging.info('Created user "{0}" in the DB'.format(self.username))

            # user already exists in database, set their admin status based on group membership (if enabled)
            if LDAP_GROUP_SECURITY:
                self.set_admin(isadmin)
            self.update_profile()
            return True
        else:
            logging.error('Unsupported authentication method')
            return False

    def create_user(self):
        """
        If user logged in successfully via LDAP in the first time
        We will create a local user (in DB) in order to manage user
        profile such as name, roles,...
        """

        # Set an invalid password hash for non local users
        self.password = '*'

        db.session.add(self)
        db.session.commit()

    def create_local_user(self):
        """
        Create local user witch stores username / password in the DB
        """
        # check if username existed
        user = User.query.filter(User.username == self.username).first()
        if user:
            return {'status': False, 'msg': 'Username is already in use'}

        # check if email existed
        user = User.query.filter(User.email == self.email).first()
        if user:
            return {'status': False, 'msg': 'Email address is already in use'}

        # first register user will be in Administrator role
        self.role_id = Role.query.filter_by(name='User').first().id
        if User.query.count() == 0:
            self.role_id = Role.query.filter_by(name='Administrator').first().id

        self.password = self.get_hashed_password(self.plain_text_password)

        if self.password:
            self.password = self.password.decode("utf-8")

        db.session.add(self)
        db.session.commit()
        return {'status': True, 'msg': 'Created user successfully'}

    def update_profile(self, enable_otp=None):
        """
        Update user profile
        """

        user = User.query.filter(User.username == self.username).first()
        if not user:
            return False

        user.firstname = self.firstname if self.firstname else user.firstname
        user.lastname = self.lastname if self.lastname else user.lastname
        user.email = self.email if self.email else user.email
        user.password = self.get_hashed_password(self.plain_text_password) if self.plain_text_password else user.password
        user.avatar = self.avatar if self.avatar else user.avatar

        if enable_otp is not None:
            user.otp_secret = ""

        if enable_otp == True:
            # generate the opt secret key
            user.otp_secret = base64.b32encode(os.urandom(10)).decode('utf-8')

        try:
            db.session.add(user)
            db.session.commit()
            return True
        except Exception:
            db.session.rollback()
            return False

    def get_domain_query(self):
        return db.session.query(User, DomainUser, Domain) \
            .filter(User.id == self.id) \
            .filter(User.id == DomainUser.user_id) \
            .filter(Domain.id == DomainUser.domain_id)

    def get_domain(self):
        """
        Get domains which user has permission to
        access
        """
        return [q[2] for q in self.get_domain_query()]

    def delete(self):
        """
        Delete a user
        """
        # revoke all user privileges first
        self.revoke_privilege()

        try:
            User.query.filter(User.username == self.username).delete()
            db.session.commit()
            return True
        except:
            db.session.rollback()
            logging.error('Cannot delete user {0} from DB'.format(self.username))
            return False

    def revoke_privilege(self):
        """
        Revoke all privielges from a user
        """
        user = User.query.filter(User.username == self.username).first()

        if user:
            user_id = user.id
            try:
                DomainUser.query.filter(DomainUser.user_id == user_id).delete()
                db.session.commit()
                return True
            except:
                db.session.rollback()
                logging.error('Cannot revoke user {0} privielges'.format(self.username))
                return False
        return False

    def set_admin(self, is_admin):
        """
        Set role for a user:
            is_admin == True  => Administrator
            is_admin == False => User
        """
        user_role_name = 'Administrator' if is_admin else 'User'
        role = Role.query.filter(Role.name==user_role_name).first()

        try:
            if role:
                user = User.query.filter(User.username==self.username).first()
                user.role_id = role.id
                db.session.commit()
                return True
            else:
                return False
        except:
            db.session.roleback()
            logging.error('Cannot change user role in DB')
            logging.debug(traceback.format_exc())
            return False


class Role(db.Model):
    id = db.Column(db.Integer, primary_key = True)
    name = db.Column(db.String(64), index=True, unique=True)
    description = db.Column(db.String(128))
    users = db.relationship('User', backref='role', lazy='dynamic')

    def __init__(self, id=None, name=None, description=None):
        self.id = id
        self.name = name
        self.description = description

    # allow database autoincrement to do its own ID assignments
    def __init__(self, name=None, description=None):
        self.id = None
        self.name = name
        self.description = description

    def __repr__(self):
        return '<Role {0}r>'.format(self.name)

class DomainSetting(db.Model):
    __tablename__ = 'domain_setting'
    id = db.Column(db.Integer, primary_key = True)
    domain_id = db.Column(db.Integer, db.ForeignKey('domain.id'))
    domain = db.relationship('Domain', back_populates='settings')
    setting = db.Column(db.String(255), nullable = False)
    value = db.Column(db.String(255))

    def __init__(self, id=None, setting=None, value=None):
        self.id = id
        self.setting = setting
        self.value = value

    def __repr__(self):
        return '<DomainSetting {0} for {1}>'.format(setting, self.domain.name)

    def __eq__(self, other):
        return self.setting == other.setting

    def set(self, value):
        try:
            self.value = value
            db.session.commit()
            return True
        except:
            logging.error('Unable to set DomainSetting value')
            logging.debug(traceback.format_exc())
            db.session.rollback()
            return False

class Domain(db.Model):
    id = db.Column(db.Integer, primary_key = True)
    name = db.Column(db.String(255), index=True, unique=True)
    master = db.Column(db.String(128))
    type = db.Column(db.String(6), nullable = False)
    serial = db.Column(db.Integer)
    notified_serial = db.Column(db.Integer)
    last_check = db.Column(db.Integer)
    dnssec = db.Column(db.Integer)
    settings = db.relationship('DomainSetting', back_populates='domain')

    def __init__(self, id=None, name=None, master=None, type='NATIVE', serial=None, notified_serial=None, last_check=None, dnssec=None):
        self.id = id
        self.name = name
        self.master = master
        self.type = type
        self.serial = serial
        self.notified_serial = notified_serial
        self.last_check = last_check
        self.dnssec = dnssec

    def __repr__(self):
        return '<Domain {0}>'.format(self.name)

    def add_setting(self, setting, value):
        try:
            self.settings.append(DomainSetting(setting=setting, value=value))
            db.session.commit()
            return True
        except Exception as e:
            logging.error('Can not create setting {0} for domain {1}. {2}'.format(setting, self.name, e))
            return False

    def get_domain_info(self, domain_name):
        """
        Get all domains which has in PowerDNS
        """
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY
        jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain_name)), headers=headers)
        return jdata

    def get_domains(self):
        """
        Get all domains which has in PowerDNS
        """
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY
        jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones'), headers=headers)
        return jdata

    def get_id_by_name(self, name):
        """
        Return domain id
        """
        try:
            domain = Domain.query.filter(Domain.name==name).first()
            return domain.id
        except:
            return None

    def update(self):
        """
        Fetch zones (domains) from PowerDNS and update into DB
        """
        db_domain = Domain.query.all()
        list_db_domain = [d.name for d in db_domain]
        dict_db_domain = dict((x.name,x) for x in db_domain)

        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY
        try:
            jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones'), headers=headers)
            list_jdomain = [d['name'].rstrip('.') for d in jdata]
            try:
                # domains should remove from db since it doesn't exist in powerdns anymore
                should_removed_db_domain = list(set(list_db_domain).difference(list_jdomain))
                for d in should_removed_db_domain:
                    # revoke permission before delete domain
                    domain = Domain.query.filter(Domain.name==d).first()
                    domain_user = DomainUser.query.filter(DomainUser.domain_id==domain.id)
                    if domain_user:
                        domain_user.delete()
                        db.session.commit()
                    domain_setting = DomainSetting.query.filter(DomainSetting.domain_id==domain.id)
                    if domain_setting:
                        domain_setting.delete()
                        db.session.commit()

                    # then remove domain
                    Domain.query.filter(Domain.name == d).delete()
                    db.session.commit()
            except:
                logging.error('Can not delete domain from DB')
                logging.debug(traceback.format_exc())
                db.session.rollback()

            # update/add new domain
            for data in jdata:
                d = dict_db_domain.get(data['name'].rstrip('.'), None)
                changed = False
                if d:
                    # existing domain, only update if something actually has changed
                    if ( d.master != str(data['masters'])
                        or d.type != data['kind']
                        or d.serial != data['serial']
                        or d.notified_serial != data['notified_serial']
                        or d.last_check != ( 1 if data['last_check'] else 0 )
                        or d.dnssec != data['dnssec'] ):

                            d.master = str(data['masters'])
                            d.type = data['kind']
                            d.serial = data['serial']
                            d.notified_serial = data['notified_serial']
                            d.last_check = 1 if data['last_check'] else 0
                            d.dnssec = 1 if data['dnssec'] else 0
                            changed = True

                else:
                    # add new domain
                    d = Domain()
                    d.name = data['name'].rstrip('.')
                    d.master = str(data['masters'])
                    d.type = data['kind']
                    d.serial = data['serial']
                    d.notified_serial = data['notified_serial']
                    d.last_check = data['last_check']
                    d.dnssec = 1 if data['dnssec'] else 0
                    db.session.add(d)
                    changed = True
                if changed:
                    try:
                        db.session.commit()
                    except:
                        db.session.rollback()
            return {'status': 'ok', 'msg': 'Domain table has been updated successfully'}
        except Exception as e:
            logging.error('Can not update domain table. Error: {0}'.format(e))
            return {'status': 'error', 'msg': 'Can not update domain table'}

    def add(self, domain_name, domain_type, soa_edit_api, domain_ns=[], domain_master_ips=[]):
        """
        Add a domain to power dns
        """
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY

        if NEW_SCHEMA:
            domain_name = domain_name + '.'
            domain_ns = [ns + '.' for ns in domain_ns]

        if soa_edit_api not in ["DEFAULT", "INCREASE", "EPOCH", "OFF"]:
            soa_edit_api = 'DEFAULT'

        elif soa_edit_api == 'OFF':
            soa_edit_api = ''

        post_data = {
            "name": domain_name,
            "kind": domain_type,
            "masters": domain_master_ips,
            "nameservers": domain_ns,
            "soa_edit_api": soa_edit_api
        }

        try:
            jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones'), headers=headers, method='POST', data=post_data)
            if 'error' in jdata.keys():
                logging.error(jdata['error'])
                return {'status': 'error', 'msg': jdata['error']}
            else:
                logging.info('Added domain {0} successfully'.format(domain_name))
                return {'status': 'ok', 'msg': 'Added domain successfully'}
        except Exception as e:
            logging.error('Cannot add domain {0}'.format(domain_name))
            logging.debug(traceback.print_exc())
            return {'status': 'error', 'msg': 'Cannot add this domain.'}

    def update_soa_setting(self, domain_name, soa_edit_api):
        domain = Domain.query.filter(Domain.name == domain_name).first()
        if not domain:
            return {'status': 'error', 'msg': 'Domain doesnt exist.'}
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY

        if soa_edit_api not in ["DEFAULT", "INCREASE", "EPOCH", "OFF"]:
            soa_edit_api = 'DEFAULT'

        elif soa_edit_api == 'OFF':
            soa_edit_api = ''

        post_data = {
            "soa_edit_api": soa_edit_api,
            "kind": domain.type
        }

        try:
            jdata = utils.fetch_json(
            urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain.name)), headers=headers,
            method='PUT', data=post_data)
            if 'error' in jdata.keys():
                logging.error(jdata['error'])
                return {'status': 'error', 'msg': jdata['error']}
            else:
                logging.info('soa-edit-api changed for domain {0} successfully'.format(domain_name))
                return {'status': 'ok', 'msg': 'soa-edit-api changed successfully'}
        except Exception as e:
            logging.debug(e)
            logging.debug(traceback.format_exc())
            logging.error('Cannot change soa-edit-api for domain {0}'.format(domain_name))
            return {'status': 'error', 'msg': 'Cannot change soa-edit-api this domain.'}

    def create_reverse_domain(self, domain_name, domain_reverse_name):
        """
        Check the existing reverse lookup domain,
        if not exists create a new one automatically
        """
        domain_obj = Domain.query.filter(Domain.name == domain_name).first()
        domain_auto_ptr = DomainSetting.query.filter(DomainSetting.domain == domain_obj).filter(DomainSetting.setting == 'auto_ptr').first()
        domain_auto_ptr = strtobool(domain_auto_ptr.value) if domain_auto_ptr else False
        system_auto_ptr = Setting.query.filter(Setting.name == 'auto_ptr').first()
        system_auto_ptr = strtobool(system_auto_ptr.value)
        self.name = domain_name
        domain_id = self.get_id_by_name(domain_reverse_name)
        if None == domain_id and \
            (
                system_auto_ptr or \
                domain_auto_ptr
            ):
            result = self.add(domain_reverse_name, 'Master', 'DEFAULT', '', '')
            self.update()
            if result['status'] == 'ok':
                history = History(msg='Add reverse lookup domain {0}'.format(domain_reverse_name), detail=str({'domain_type': 'Master', 'domain_master_ips': ''}), created_by='System')
                history.add()
            else:
                return {'status': 'error', 'msg': 'Adding reverse lookup domain failed'}
            domain_user_ids = self.get_user()
            domain_users = []
            u = User()
            for uid in domain_user_ids:
                u.id = uid
                tmp = u.get_user_info_by_id()
                domain_users.append(tmp.username)
            if 0 != len(domain_users):
                self.name = domain_reverse_name
                self.grant_privielges(domain_users)
                return {'status': 'ok', 'msg': 'New reverse lookup domain created with granted privilages'}
            return {'status': 'ok', 'msg': 'New reverse lookup domain created without users'}
        return {'status': 'ok', 'msg': 'Reverse lookup domain already exists'}

    def get_reverse_domain_name(self, reverse_host_address):
        c = 1
        if re.search('ip6.arpa', reverse_host_address):
            for i in range(1,32,1):
                address = re.search('((([a-f0-9]\.){'+ str(i) +'})(?P<ipname>.+6.arpa)\.?)', reverse_host_address)
                if None != self.get_id_by_name(address.group('ipname')):
                    c = i
                    break
            return re.search('((([a-f0-9]\.){'+ str(c) +'})(?P<ipname>.+6.arpa)\.?)', reverse_host_address).group('ipname')
        else:
            for i in range(1,4,1):
                address = re.search('((([0-9]+\.){'+ str(i) +'})(?P<ipname>.+r.arpa)\.?)', reverse_host_address)
                if None != self.get_id_by_name(address.group('ipname')):
                    c = i
                    break
            return re.search('((([0-9]+\.){'+ str(c) +'})(?P<ipname>.+r.arpa)\.?)', reverse_host_address).group('ipname')

    def delete(self, domain_name):
        """
        Delete a single domain name from powerdns
        """
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY
        try:
            jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain_name)), headers=headers, method='DELETE')
            logging.info('Delete domain {0} successfully'.format(domain_name))
            return {'status': 'ok', 'msg': 'Delete domain successfully'}
        except Exception as e:
            logging.error('Cannot delete domain {0}'.format(domain_name))
            logging.debug(traceback.print_exc())
            return {'status': 'error', 'msg': 'Cannot delete domain'}

    def get_user(self):
        """
        Get users (id) who have access to this domain name
        """
        user_ids = []
        query = db.session.query(DomainUser, Domain).filter(User.id==DomainUser.user_id).filter(Domain.id==DomainUser.domain_id).filter(Domain.name==self.name).all()
        for q in query:
            user_ids.append(q[0].user_id)
        return user_ids

    def grant_privielges(self, new_user_list):
        """
        Reconfigure domain_user table
        """

        domain_id = self.get_id_by_name(self.name)

        domain_user_ids = self.get_user()
        new_user_ids = [u.id for u in User.query.filter(User.username.in_(new_user_list)).all()] if new_user_list else []

        removed_ids = list(set(domain_user_ids).difference(new_user_ids))
        added_ids = list(set(new_user_ids).difference(domain_user_ids))

        try:
            for uid in removed_ids:
                DomainUser.query.filter(DomainUser.user_id == uid).filter(DomainUser.domain_id==domain_id).delete()
                db.session.commit()
        except:
            db.session.rollback()
            logging.error('Cannot revoke user privielges on domain {0}'.format(self.name))

        try:
            for uid in added_ids:
                du = DomainUser(domain_id, uid)
                db.session.add(du)
                db.session.commit()
        except:
            db.session.rollback()
            logging.error('Cannot grant user privielges to domain {0}'.format(self.name))


    def update_from_master(self, domain_name):
        """
        Update records from Master DNS server
        """
        domain = Domain.query.filter(Domain.name == domain_name).first()
        if domain:
            headers = {}
            headers['X-API-Key'] = PDNS_API_KEY
            try:
                jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}/axfr-retrieve'.format(domain.name)), headers=headers, method='PUT')
                return {'status': 'ok', 'msg': 'Update from Master successfully'}
            except:
                return {'status': 'error', 'msg': 'There was something wrong, please contact administrator'}
        else:
            return {'status': 'error', 'msg': 'This domain doesnot exist'}

    def get_domain_dnssec(self, domain_name):
        """
        Get domain DNSSEC information
        """
        domain = Domain.query.filter(Domain.name == domain_name).first()
        if domain:
            headers = {}
            headers['X-API-Key'] = PDNS_API_KEY
            try:
                jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}/cryptokeys'.format(domain.name)), headers=headers, method='GET')
                if 'error' in jdata:
                    return {'status': 'error', 'msg': 'DNSSEC is not enabled for this domain'}
                else:
                    return {'status': 'ok', 'dnssec': jdata}
            except:
                return {'status': 'error', 'msg': 'There was something wrong, please contact administrator'}
        else:
            return {'status': 'error', 'msg': 'This domain doesnot exist'}

    def enable_domain_dnssec(self, domain_name):
        """
        Enable domain DNSSEC
        """
        domain = Domain.query.filter(Domain.name == domain_name).first()
        if domain:
            headers = {}
            headers['X-API-Key'] = PDNS_API_KEY
            try:
                # Enable API-RECTIFY for domain, BEFORE activating DNSSEC
                post_data = {
                    "api_rectify": True
                }
                jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain.name)), headers=headers, method='PUT', data=post_data)
                if 'error' in jdata:
                    return {'status': 'error', 'msg': 'API-RECTIFY could not be enabled for this domain', 'jdata' : jdata}

                # Activate DNSSEC
                post_data = {
                    "keytype": "ksk",
                    "active": True
                }
                jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}/cryptokeys'.format(domain.name)), headers=headers, method='POST',data=post_data)
                if 'error' in jdata:
                    return {'status': 'error', 'msg': 'Cannot enable DNSSEC for this domain. Error: {0}'.format(jdata['error']), 'jdata' : jdata}

                return {'status': 'ok'}

            except:
                logging.error(traceback.print_exc())
                return {'status': 'error', 'msg': 'There was something wrong, please contact administrator'}

        else:
            return {'status': 'error', 'msg': 'This domain does not exist'}

    def delete_dnssec_key(self, domain_name, key_id):
        """
        Remove keys DNSSEC
        """
        domain = Domain.query.filter(Domain.name == domain_name).first()
        if domain:
            headers = {}
            headers['X-API-Key'] = PDNS_API_KEY
            try:
                # Deactivate DNSSEC
                jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}/cryptokeys/{1}'.format(domain.name, key_id)), headers=headers, method='DELETE')
                if jdata != True:
                    return {'status': 'error', 'msg': 'Cannot disable DNSSEC for this domain. Error: {0}'.format(jdata['error']), 'jdata' : jdata}

                # Disable API-RECTIFY for domain, AFTER deactivating DNSSEC
                post_data = {
                    "api_rectify": False
                }
                jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain.name)), headers=headers, method='PUT', data=post_data)
                if 'error' in jdata:
                    return {'status': 'error', 'msg': 'API-RECTIFY could not be disabled for this domain', 'jdata' : jdata}

                return {'status': 'ok'}

            except:
                logging.error(traceback.print_exc())
                return {'status': 'error', 'msg': 'There was something wrong, please contact administrator','domain': domain.name, 'id': key_id}

        else:
            return {'status': 'error', 'msg': 'This domain doesnot exist'}


class DomainUser(db.Model):
    __tablename__ = 'domain_user'
    id = db.Column(db.Integer, primary_key = True)
    domain_id = db.Column(db.Integer, db.ForeignKey('domain.id'), nullable = False)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable = False)

    def __init__(self, domain_id, user_id):
        self.domain_id = domain_id
        self.user_id = user_id

    def __repr__(self):
        return '<Domain_User {0} {1}>'.format(self.domain_id, self.user_id)


class Record(object):
    """
    This is not a model, it's just an object
    which be assigned data from PowerDNS API
    """

    def __init__(self, name=None, type=None, status=None, ttl=None, data=None):
        self.name = name
        self.type = type
        self.status = status
        self.ttl = ttl
        self.data = data

    def get_record_data(self, domain):
        """
        Query domain's DNS records via API
        """
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY
        try:
            jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain)), headers=headers)
        except:
            logging.error("Cannot fetch domain's record data from remote powerdns api")
            return False

        if NEW_SCHEMA:
            rrsets = jdata['rrsets']
            for rrset in rrsets:
                r_name = rrset['name'].rstrip('.')
                if PRETTY_IPV6_PTR: # only if activated
                    if rrset['type'] == 'PTR': # only ptr
                        if 'ip6.arpa' in r_name: # only if v6-ptr
                            r_name = dns.reversename.to_address(dns.name.from_text(r_name))

                rrset['name'] = r_name
                rrset['content'] = rrset['records'][0]['content']
                rrset['disabled'] = rrset['records'][0]['disabled']
            return {'records': rrsets}

        return jdata

    def add(self, domain):
        """
        Add a record to domain
        """
        # validate record first
        r = self.get_record_data(domain)
        records = r['records']
        check = list(filter(lambda check: check['name'] == self.name, records))
        if check:
            r = check[0]
            if r['type'] in ('A', 'AAAA' ,'CNAME'):
                return {'status': 'error', 'msg': 'Record already exists with type "A", "AAAA" or "CNAME"'}

        # continue if the record is ready to be added
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY

        if NEW_SCHEMA:
            data = {"rrsets": [
                        {
                            "name": self.name.rstrip('.') + '.',
                            "type": self.type,
                            "changetype": "REPLACE",
                            "ttl": self.ttl,
                            "records": [
                                {
                                    "content": self.data,
                                    "disabled": self.status,
                                }
                            ]
                        }
                    ]
                }
        else:
            data = {"rrsets": [
                        {
                            "name": self.name,
                            "type": self.type,
                            "changetype": "REPLACE",
                            "records": [
                                {
                                    "content": self.data,
                                    "disabled": self.status,
                                    "name": self.name,
                                    "ttl": self.ttl,
                                    "type": self.type
                                }
                            ]
                        }
                    ]
                }

        try:
            jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain)), headers=headers, method='PATCH', data=data)
            logging.debug(jdata)
            return {'status': 'ok', 'msg': 'Record was added successfully'}
        except Exception as e:
            logging.error("Cannot add record {0}/{1}/{2} to domain {3}. DETAIL: {4}".format(self.name, self.type, self.data, domain, e))
            return {'status': 'error', 'msg': 'There was something wrong, please contact administrator'}


    def compare(self, domain_name, new_records):
        """
        Compare new records with current powerdns record data
        Input is a list of hashes (records)
        """
        # get list of current records we have in powerdns
        current_records = self.get_record_data(domain_name)['records']

        # convert them to list of list (just has [name, type]) instead of list of hash
        # to compare easier
        list_current_records = [[x['name'],x['type']] for x in current_records]
        list_new_records = [[x['name'],x['type']] for x in new_records]

        # get list of deleted records
        # they are the records which exist in list_current_records but not in list_new_records
        list_deleted_records = [x for x in list_current_records if x not in list_new_records]

        # convert back to list of hash
        deleted_records = [x for x in current_records if [x['name'],x['type']] in list_deleted_records and (x['type'] in app.config['RECORDS_ALLOW_EDIT'] and x['type'] != 'SOA')]

        # return a tuple
        return deleted_records, new_records


    def apply(self, domain, post_records):
        """
        Apply record changes to domain
        """
        records = []
        for r in post_records:
            r_name = domain if r['record_name'] in ['@', ''] else r['record_name'] + '.' + domain
            r_type = r['record_type']
            if PRETTY_IPV6_PTR: # only if activated
                if NEW_SCHEMA: # only if new schema
                    if r_type == 'PTR': # only ptr
                        if ':' in r['record_name']: # dirty ipv6 check
                            r_name = r['record_name']

            record = {
                        "name": r_name,
                        "type": r_type,
                        "content": r['record_data'],
                        "disabled": True if r['record_status'] == 'Disabled' else False,
                        "ttl": int(r['record_ttl']) if r['record_ttl'] else 3600,
                    }
            records.append(record)

        deleted_records, new_records = self.compare(domain, records)

        records = []
        for r in deleted_records:
            r_name = r['name'].rstrip('.') + '.' if NEW_SCHEMA else r['name']
            r_type = r['type']
            if PRETTY_IPV6_PTR: # only if activated
                if NEW_SCHEMA: # only if new schema
                    if r_type == 'PTR': # only ptr
                        if ':' in r['name']: # dirty ipv6 check
                            r_name = dns.reversename.from_address(r['name']).to_text()

            record = {
                        "name": r_name,
                        "type": r_type,
                        "changetype": "DELETE",
                        "records": [
                        ]
                    }
            records.append(record)

        postdata_for_delete = {"rrsets": records}

        records = []
        for r in new_records:
            if NEW_SCHEMA:
                r_name = r['name'].rstrip('.') + '.'
                r_type = r['type']
                if PRETTY_IPV6_PTR: # only if activated
                    if r_type == 'PTR': # only ptr
                        if ':' in r['name']: # dirty ipv6 check
                            r_name = r['name']

                record = {
                            "name": r_name,
                            "type": r_type,
                            "changetype": "REPLACE",
                            "ttl": r['ttl'],
                            "records": [
                                {
                                    "content": r['content'],
                                    "disabled": r['disabled'],
                                }
                            ]
                        }
            else:
                record = {
                            "name": r['name'],
                            "type": r['type'],
                            "changetype": "REPLACE",
                            "records": [
                                {
                                    "content": r['content'],
                                    "disabled": r['disabled'],
                                    "name": r['name'],
                                    "ttl": r['ttl'],
                                    "type": r['type'],
                                    "priority": 10, # priority field for pdns 3.4.1. https://doc.powerdns.com/md/authoritative/upgrading/
                                }
                            ]
                        }

            records.append(record)

        # Adjustment to add multiple records which described in https://github.com/ngoduykhanh/PowerDNS-Admin/issues/5#issuecomment-181637576
        final_records = []
        records = sorted(records, key = lambda item: (item["name"], item["type"], item["changetype"]))
        for key, group in itertools.groupby(records, lambda item: (item["name"], item["type"], item["changetype"])):
            if NEW_SCHEMA:
                r_name = key[0]
                r_type = key[1]
                r_changetype = key[2]

                if PRETTY_IPV6_PTR: # only if activated
                    if r_type == 'PTR': # only ptr
                        if ':' in r_name: # dirty ipv6 check
                            r_name = dns.reversename.from_address(r_name).to_text()

                new_record = {
                        "name": r_name,
                        "type": r_type,
                        "changetype": r_changetype,
                        "ttl": None,
                        "records": []
                    }
                for item in group:
                    temp_content = item['records'][0]['content']
                    temp_disabled = item['records'][0]['disabled']
                    if key[1] in ['MX', 'CNAME', 'SRV', 'NS']:
                        if temp_content.strip()[-1:] != '.':
                            temp_content += '.'

                    if new_record['ttl'] is None:
                        new_record['ttl'] = item['ttl']
                    new_record['records'].append({
                        "content": temp_content,
                        "disabled": temp_disabled
                    })
                final_records.append(new_record)

            else:

                final_records.append({
                        "name": key[0],
                        "type": key[1],
                        "changetype": key[2],
                        "records": [
                            {
                                "content": item['records'][0]['content'],
                                "disabled": item['records'][0]['disabled'],
                                "name": key[0],
                                "ttl": item['records'][0]['ttl'],
                                "type": key[1],
                                "priority": 10,
                            } for item in group
                        ]
                    })

        postdata_for_new = {"rrsets": final_records}
        logging.info(postdata_for_new)
        logging.info(postdata_for_delete)
        logging.info(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain)))
        try:
            headers = {}
            headers['X-API-Key'] = PDNS_API_KEY
            jdata1 = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain)), headers=headers, method='PATCH', data=postdata_for_delete)
            jdata2 = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain)), headers=headers, method='PATCH', data=postdata_for_new)

            if 'error' in jdata2.keys():
                logging.error('Cannot apply record changes.')
                logging.debug(jdata2['error'])
                return {'status': 'error', 'msg': jdata2['error']}
            else:
                self.auto_ptr(domain, new_records, deleted_records)
                self.update_db_serial(domain)
                logging.info('Record was applied successfully.')
                return {'status': 'ok', 'msg': 'Record was applied successfully'}
        except Exception as e:
            logging.error("Cannot apply record changes to domain {0}. DETAIL: {1}".format(e, domain))
            return {'status': 'error', 'msg': 'There was something wrong, please contact administrator'}

    def auto_ptr(self, domain, new_records, deleted_records):
        """
        Add auto-ptr records
        """
        domain_obj = Domain.query.filter(Domain.name == domain).first()
        domain_auto_ptr = DomainSetting.query.filter(DomainSetting.domain == domain_obj).filter(DomainSetting.setting == 'auto_ptr').first()
        domain_auto_ptr = strtobool(domain_auto_ptr.value) if domain_auto_ptr else False

        system_auto_ptr = Setting.query.filter(Setting.name == 'auto_ptr').first()
        system_auto_ptr = strtobool(system_auto_ptr.value)

        if system_auto_ptr or domain_auto_ptr:
            try:
                d = Domain()
                for r in new_records:
                    if r['type'] in ['A', 'AAAA']:
                        r_name = r['name'] + '.'
                        r_content = r['content']
                        reverse_host_address = dns.reversename.from_address(r_content).to_text()
                        domain_reverse_name = d.get_reverse_domain_name(reverse_host_address)
                        d.create_reverse_domain(domain, domain_reverse_name)
                        self.name = dns.reversename.from_address(r_content).to_text().rstrip('.')
                        self.type = 'PTR'
                        self.status = r['disabled']
                        self.ttl = r['ttl']
                        self.data = r_name
                        self.add(domain_reverse_name)
                for r in deleted_records:
                    if r['type'] in ['A', 'AAAA']:
                        r_name = r['name'] + '.'
                        r_content = r['content']
                        reverse_host_address = dns.reversename.from_address(r_content).to_text()
                        domain_reverse_name = d.get_reverse_domain_name(reverse_host_address)
                        self.name = reverse_host_address
                        self.type = 'PTR'
                        self.data = r_content
                        self.delete(domain_reverse_name)
                return {'status': 'ok', 'msg': 'Auto-PTR record was updated successfully'}
            except Exception as e:
                logging.error("Cannot update auto-ptr record changes to domain {0}. DETAIL: {1}".format(domain, e))
                return {'status': 'error', 'msg': 'Auto-PTR creation failed. There was something wrong, please contact administrator.'}

    def delete(self, domain):
        """
        Delete a record from domain
        """
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY
        data = {"rrsets": [
                    {
                        "name": self.name.rstrip('.') + '.',
                        "type": self.type,
                        "changetype": "DELETE",
                        "records": [
                        ]
                    }
                ]
            }
        try:
            jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain)), headers=headers, method='PATCH', data=data)
            logging.debug(jdata)
            return {'status': 'ok', 'msg': 'Record was removed successfully'}
        except:
            logging.error("Cannot remove record {0}/{1}/{2} from domain {3}".format(self.name, self.type, self.data, domain))
            return {'status': 'error', 'msg': 'There was something wrong, please contact administrator'}

    def is_allowed_edit(self):
        """
        Check if record is allowed to edit
        """
        return self.type in app.config['RECORDS_ALLOW_EDIT']

    def is_allowed_delete(self):
        """
        Check if record is allowed to removed
        """
        return (self.type in app.config['RECORDS_ALLOW_EDIT'] and self.type != 'SOA')

    def exists(self, domain):
        """
        Check if record is present within domain records, and if it's present set self to found record
        """
        jdata = self.get_record_data(domain)
        jrecords = jdata['records']

        for jr in jrecords:
            if jr['name'] == self.name:
                self.name = jr['name']
                self.type = jr['type']
                self.status = jr['disabled']
                self.ttl = jr['ttl']
                self.data = jr['content']
                self.priority = 10
                return True
        return False

    def update(self, domain, content):
        """
        Update single record
        """
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY

        if NEW_SCHEMA:
            data = {"rrsets": [
                        {
                            "name": self.name + '.',
                            "type": self.type,
                            "ttl": self.ttl,
                            "changetype": "REPLACE",
                            "records": [
                                {
                                    "content": content,
                                    "disabled": self.status,
                                }
                            ]
                        }
                    ]
                }
        else:
            data = {"rrsets": [
                        {
                            "name": self.name,
                            "type": self.type,
                            "changetype": "REPLACE",
                            "records": [
                                {
                                    "content": content,
                                    "disabled": self.status,
                                    "name": self.name,
                                    "ttl": self.ttl,
                                    "type": self.type,
                                    "priority": 10
                                }
                            ]
                        }
                    ]
                }
        try:
            jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain)), headers=headers, method='PATCH', data=data)
            logging.debug("dyndns data: {0}".format(data))
            return {'status': 'ok', 'msg': 'Record was updated successfully'}
        except Exception as e:
            logging.error("Cannot add record {0}/{1}/{2} to domain {3}. DETAIL: {4}".format(self.name, self.type, self.data, domain, e))
            return {'status': 'error', 'msg': 'There was something wrong, please contact administrator'}

    def update_db_serial(self, domain):
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY
        jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/localhost/zones/{0}'.format(domain)), headers=headers, method='GET')
        serial = jdata['serial']

        domain = Domain.query.filter(Domain.name==domain).first()
        if domain:
            domain.serial = serial
            db.session.commit()
            return {'status': True, 'msg': 'Synced local serial for domain name {0}'.format(domain)}
        else:
            return {'status': False, 'msg': 'Could not find domain name {0} in local db'.format(domain)}


class Server(object):
    """
    This is not a model, it's just an object
    which be assigned data from PowerDNS API
    """

    def __init__(self, server_id=None, server_config=None):
        self.server_id = server_id
        self.server_config = server_config

    def get_config(self):
        """
        Get server config
        """
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY

        try:
            jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/{0}/config'.format(self.server_id)), headers=headers, method='GET')
            return jdata
        except:
            logging.error("Can not get server configuration.")
            logging.debug(traceback.format_exc())
            return []

    def get_statistic(self):
        """
        Get server statistics
        """
        headers = {}
        headers['X-API-Key'] = PDNS_API_KEY

        try:
            jdata = utils.fetch_json(urljoin(PDNS_STATS_URL, API_EXTENDED_URL + '/servers/{0}/statistics'.format(self.server_id)), headers=headers, method='GET')
            return jdata
        except:
            logging.error("Can not get server statistics.")
            logging.debug(traceback.format_exc())
            return []


class History(db.Model):
    id = db.Column(db.Integer, primary_key = True)
    msg = db.Column(db.String(256))
    detail = db.Column(db.Text().with_variant(db.Text(length=2**24-2), 'mysql'))
    created_by = db.Column(db.String(128))
    created_on = db.Column(db.DateTime, default=datetime.utcnow)

    def __init__(self, id=None, msg=None, detail=None, created_by=None):
        self.id = id
        self.msg = msg
        self.detail = detail
        self.created_by = created_by

    def __repr__(self):
        return '<History {0}>'.format(self.msg)

    def add(self):
        """
        Add an event to history table
        """
        h = History()
        h.msg = self.msg
        h.detail = self.detail
        h.created_by = self.created_by
        db.session.add(h)
        db.session.commit()

    def remove_all(self):
        """
        Remove all history from DB
        """
        try:
            num_rows_deleted = db.session.query(History).delete()
            db.session.commit()
            logging.info("Removed all history")
            return True
        except:
            db.session.rollback()
            logging.error("Cannot remove history")
            logging.debug(traceback.format_exc())
            return False

class Setting(db.Model):
    id = db.Column(db.Integer, primary_key = True)
    name = db.Column(db.String(64))
    value = db.Column(db.String(256))

    def __init__(self, id=None, name=None, value=None):
        self.id = id
        self.name = name
        self.value = value

    # allow database autoincrement to do its own ID assignments
    def __init__(self, name=None, value=None):
        self.id = None
        self.name = name
        self.value = value

    def set_mainteance(self, mode):
        """
        mode = True/False
        """
        mode = str(mode)
        maintenance = Setting.query.filter(Setting.name=='maintenance').first()
        try:
            if maintenance:
                if maintenance.value != mode:
                    maintenance.value = mode
                    db.session.commit()
                return True
            else:
                s = Setting(name='maintenance', value=mode)
                db.session.add(s)
                db.session.commit()
                return True
        except:
            logging.error('Cannot set maintenance to {0}'.format(mode))
            logging.debug(traceback.format_exc())
            db.session.rollback()
            return False

    def toggle(self, setting):
        setting = str(setting)
        current_setting = Setting.query.filter(Setting.name==setting).first()
        try:
            if current_setting:
                if current_setting.value == "True":
                    current_setting.value = "False"
                else:
                    current_setting.value = "True"
                db.session.commit()
                return True
            else:
                logging.error('Setting {0} does not exist'.format(setting))
                return False
        except:
            logging.error('Cannot toggle setting {0}'.format(setting))
            logging.debug(traceback.format_exec())
            db.session.rollback()
            return False

    def set(self, setting, value):
        setting = str(setting)
        new_value = str(value)
        current_setting = Setting.query.filter(Setting.name==setting).first()
        try:
            if current_setting:
                current_setting.value = new_value
                db.session.commit()
                return True
            else:
                logging.error('Setting {0} does not exist'.format(setting))
                return False
        except:
            logging.error('Cannot edit setting {0}'.format(setting))
            logging.debug(traceback.format_exec())
            db.session.rollback()
            return False


class DomainTemplate(db.Model):
    __tablename__ = "domain_template"
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(255), index=True, unique=True)
    description = db.Column(db.String(255))
    records = db.relationship('DomainTemplateRecord', back_populates='template', cascade="all, delete-orphan")

    def __repr__(self):
        return '<DomainTemplate {0}>'.format(self.name)

    def __init__(self, name=None, description=None):
        self.id = None
        self.name = name
        self.description = description

    def replace_records(self, records):
        try:
            self.records = []
            for record in records:
                self.records.append(record)
            db.session.commit()
            return {'status': 'ok', 'msg': 'Template records have been modified'}
        except Exception as e:
            logging.error('Cannot create template records Error: {0}'.format(e))
            db.session.rollback()
            return {'status': 'error', 'msg': 'Can not create template records'}

    def create(self):
        try:
            db.session.add(self)
            db.session.commit()
            return {'status': 'ok', 'msg': 'Template has been created'}
        except Exception as e:
            logging.error('Can not update domain template table. Error: {0}'.format(e))
            db.session.rollback()
            return {'status': 'error', 'msg': 'Can not update domain template table'}

    def delete_template(self):
        try:
            self.records = []
            db.session.delete(self)
            db.session.commit()
            return {'status': 'ok', 'msg': 'Template has been deleted'}
        except Exception as e:
            logging.error('Can not delete domain template. Error: {0}'.format(e))
            db.session.rollback()
            return {'status': 'error', 'msg': 'Can not delete domain template'}


class DomainTemplateRecord(db.Model):
    __tablename__ = "domain_template_record"
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(255))
    type = db.Column(db.String(64))
    ttl = db.Column(db.Integer)
    data = db.Column(db.Text)
    status = db.Column(db.Boolean)
    template_id = db.Column(db.Integer, db.ForeignKey('domain_template.id'))
    template = db.relationship('DomainTemplate', back_populates='records')

    def __repr__(self):
        return '<DomainTemplateRecord {0}>'.format(self.id)

    def __init__(self, id=None, name=None, type=None, ttl=None, data=None, status=None):
        self.id = id
        self.name = name
        self.type = type
        self.ttl = ttl
        self.data = data
        self.status = status

    def apply(self):
        try:
            db.session.commit()
        except Exception as e:
            logging.error('Can not update domain template table. Error: {0}'.format(e))
            db.session.rollback()
            return {'status': 'error', 'msg': 'Can not update domain template table'}