Send notification through IFTTT when ARCH ENEMY ticket information has been updated

lambda_handler.py

import json
import urllib.request
from html.parser import HTMLParser

# Define URLs
SOURCE_URL = 'https://www.creativeman.co.jp/event/arch_e2018/'
IFTTT_ENDPOINT = 'https://maker.ifttt.com/trigger/arch_enemy_concert_parsed/with/key/cTU_U2Z-OUABzEYyhS3EFe'


class Parser(HTMLParser):
    '''Parse the ticket information page'''
    def __init__(self):
        HTMLParser.__init__(self)
        self.events = []
        self.__event = None
        self.__key = 0
        self.__inside_the_table = False
        self.__node = None

    def handle_starttag(self, tag, attrs):
        attrs = dict(attrs)

        if tag == 'table' and attrs['class'] == 'event-table':
            self.__inside_the_table = True
            self.__key = -1
            self.__event = []

        if self.__inside_the_table:
            self.__node = {'tag': tag, 'attrs': attrs}

    def handle_endtag(self, tag):
        if tag == 'table'  and self.__inside_the_table:
            self.__inside_the_table = False
            self.events.append(self.__event)
            self.__event = None


    def handle_data(self, data):
        if self.__inside_the_table == False:
            return

        if self.__node['tag'] == 'tr':
            self.__key += 1
            self.__event.append([])

        if data.strip():
            self.__event[self.__key].append(data.strip())


def ifttt_parameter(parameters, new_value):
    '''add new_value to given parameters dict'''
    index = str(len(parameters.keys()) + 1)
    parameters['value' + index] = new_value


def ifttt_notify(parameters):
    '''send notification on IFTTT'''
    params_json = json.dumps(parameters).encode('utf8')
    req = urllib.request.Request(
        IFTTT_ENDPOINT,
        data=params_json,
        headers={'content-type': 'application/json'}
    )
    response = urllib.request.urlopen(req)
    if response.status != 200:
        raise Exception('IFTTT dosen\'t response 200')

def fetch_html(url):
    '''Fetch a html document from the web'''
    response = urllib.request.urlopen(url)
    if response.status != 200:
        raise Exception('The souce page dosen\'t response 200')

    return response.read().decode('utf8')

def fake_html(*args):
    contet = None
    with open('/tmp/fake.html', 'r') as fp:
        content = fp.read()

    return content


# main
def lambda_handler(event, context):
    try:
        content = fetch_html(SOURCE_URL)
        # content = fake_html(SOURCE_URL)

        parser = Parser()
        parser.feed(content)

        # - build notification parameters
        notification_parameters = {}
        for event in parser.events:
            if '東京' in event[0][0] and event[3][1] != '調整中':
                ifttt_parameter(notification_parameters, event[0][0][:12] + ':' + ':'.join(event[3][1:]))
    except(Error):
        ifttt_parameter(notification_parameters, 'Failed to parse the page.')

    if len(notification_parameters.keys()) > 0:
        ifttt_parameter(notification_parameters, SOURCE_URL)
        return "Something has changed!"
    else:
        return "Nothing has change.."