Hello from serverless messanger chatbot. Read more: http://qooba.net/index.php/2018/07/22/hello-from-serverless-messanger-chatbot/

aws_lambda_apigateway.png

aws_lambda_code.png

aws_lambda_config.png

chatbot.py

"""messanger chatbot"""
import binascii
import hmac
import json
import os
import urllib
from hashlib import sha1

verify_token = os.environ["verify_token"]
access_token = os.environ["access_token"]
app_secret = os.environ["app_secret"]

# lambda entry point
def lambda_handler(event, context):
    """lambda entrypoint"""

    print(event)
    try:
        query_string_parameters = event["queryStringParameters"]
        if query_string_parameters != None:
            hub_mode = query_string_parameters["hub.mode"]
            hub_challenge = query_string_parameters["hub.challenge"]
            hub_verify_token = query_string_parameters["hub.verify_token"]

            # handling verification request
            if hub_mode == "subscribe" and verify_token == hub_verify_token:
                return {
                    'statusCode': 200,
                    'body': hub_challenge,
                    'headers': {
                        'Content-Type': 'text/plain'
                    }
                }

        body = event["body"]
        headers = event["headers"]

        # here we verify the webhook signature
        if headers["X-Hub-Signature"].replace('sha1=', '') != hmac_sha1(body):
            return {'statusCode': 200}

        # finally we parse the message
        for entry in json.loads(body)["entry"]:
            for message in entry["messaging"]:
                if message.get("message", None) != None:
                    publish_message(message)

    except Exception as ex:
        print(ex)

    return {'statusCode': 200}


def publish_message(message):
    """publish message"""
    
    base_url = 'https://graph.facebook.com/v2.6/me/messages?access_token={}'
    url = base_url.format(access_token)
    sender_id = message['sender']['id']

    # here we parse the message intent
    if parse_intent(message) == 'hungry':
        text = "Bon Appetit :)"
    else:    
        text = "Hello from serverless messanger chatbot !!!"

    my_message = {"recipient": {"id": sender_id}, "message": {"text": text}}

    req = urllib.request.Request(url)
    data = urllib.parse.urlencode(my_message).encode('utf-8')
    urllib.request.urlopen(req, data=data)

def parse_intent(message):
    try:
        nlp = message['message']['nlp']
        intent = nlp['entities']['intent'][0]['value']    
        return intent
    except KeyError:
        return None

def hmac_sha1(input_str):
    """calculate hmac"""
    raw = input_str.encode("utf-8")
    key = app_secret.encode('utf-8')
    hashed = hmac.new(key, raw, sha1)
    return str(binascii.hexlify(hashed.digest())).lstrip('b').strip("'")

chatbot_hello.png

facebook_app_events.png

facebook_app_messanger.png

facebook_app_nlp.png

facebook_appid_appsecret.png

facebook_wit.png

webhook.json

{
    "object": "page",
    "entry": [
        {
            "id": "*********************",
            "time": 1532132321321,
            "messaging": [
                {
                    "sender": {
                        "id": "****************"
                    },
                    "recipient": {
                        "id": "*****************"
                    },
                    "timestamp": 1532123213213,
                    "message": {
                        "mid": "***************************",
                        "seq": 222222,
                        "text": "I want to eat pizza",
                        "nlp": {
                            "entities": {
                                "dish": [
                                    {
                                        "confidence": 0.91639471779845,
                                        "value": "pizza",
                                        "type": "value",
                                        "_entity": "dish",
                                        "_body": "pizza",
                                        "_start": 15,
                                        "_end": 20
                                    }
                                ],
                                "intent": [
                                    {
                                        "confidence": 0.99276725775628,
                                        "value": "hungry",
                                        "_entity": "intent"
                                    }
                                ]
                            }
                        }
                    }
                }
            ]
        }
    ]
}