Write a Facebook messenger bot in Python3

Jim

Outline

Some basic knowledges and some requirements

Setup server with FB

Write an echo bot

Further configuration

Communicate with FB

FB Server

To react with FB, we need a web api server which accept

FB’s message and response to it.

Response to a message

FB Server

Response to a message

FB Server

Response to a message

FB Server My Server

Recall

How we get a web page?

We type an url address (ip address) onto the location bar

Chrome sends a request to the server

Server responses us with corresponded return

Web server

To finish a web request, you need

An IP address

A Server

Accept HTTP Protocol

HTTP

A way to communicate with server

A general way to exchange information

Ask for resources from server (request)

Server returns if a request is valid (response)

Request and Response

My ServerGET /index.html

HTML Content

Try with command line

$ telnet www.google.com 80

GET / HTTP/1.1

(enter)

Methods

GET (Usually used for get web page)

POST (Usually used for submit a form)

Others (PUT, DELETE, OPTION) (Won’t mention today)

Parameters

Query string (on the url link)

Form submit body

Raw body <— We will use today

Headers

HTTPS

What is HTTPS? HTTP with Secure

Why HTTPS

Make you info secure

Create a security tunnel before data transfer

How to setup it? It’s complicated…

API

Application Programming Interface

A way to offer resources

Could be a server or a library

Sample codes

https://github.com/lemonlatte/myCurrencyBot

Write you own API server

Flask

Flask is a simple but flexible and powerful web framework

Strong community support

Setup a local environment

$ virtualenv -p python3 .venv

$ . .venv/bin/activate

exit

Before this, we need to setup your python environment

$ pip3 install flask

First web server

#!/usr/bin/env python

from flask import Flaskfrom flask import abortfrom flask import requestapp = Flask(__name__)

@app.route("/version", methods=['GET'])def version(): if request.method == 'GET': return "0.1" else: abort(404)

if __name__ == "__main__": app.run(port=11123)

Try telnet to your web server

$ telnet localhost 11123Trying ::1...Trying 127.0.0.1...Connected to localhost.Escape character is '^]'.GET /version HTTP/1.1

HTTP/1.0 200 OKContent-Type: text/html; charset=utf-8Content-Length: 3Server: Werkzeug/0.12.1 Python/3.5.2Date: Sun, 16 Apr 2017 15:54:35 GMT

0.1Connection closed by foreign host.(enter)

Start building a bot

Now, we need a web server

FB Server My Server

What we have to do?

Set up you account on Facebook

Write a web server

1. Go https://developers.facebook.com

2. My Apps —> Add a New App

3. Add Product —> Messenger —> Get Started

4. Setup Webhooks, you need

a. A callback url (require HTTPS)

b. A random string as the token

5. Subscription Fields: messages, messaging_postbacks

How to setup a bot (I)

Setup Webhooks

BOT_TOKEN = "your-random-string"

@app.route("/fbCallback", methods=['GET', 'POST'])def fb_cb_handler(): if request.method == 'GET': token = request.args.get('hub.verify_token') if token == BOT_TOKEN: return request.args.get('hub.challenge') else: abort(403) else: abort(405)

Echo Bot

A web call accept requests from FB

Parse data from FB

Return a text response to FB

How to setup a bot (II)

1. Create a fan page

2. Create a new App in “facebook developers” page

a. Category : Brand or Product / App Page

3. Back to developer page:

a. Generate page access token

b. Subscribe messages from your page

Get messages

def fb_post_handler(req): print(req.get_data()) resp_body = req.get_json() return ""

@app.route("/fbCallback", methods=['GET', 'POST'])def fb_cb_handler(): if request.method == 'GET': . . . elif request.method == 'POST': return fb_post_handler(request) else: . . .

Test - talk to your bot

Payload{ "object": "page", "entry": [ { "id": "708403975999401", "time": 1492008179540, "messaging": [ { "sender": { "id": "1433303610077218" }, "recipient": { "id": "708403975999401" }, "timestamp": 1492008179350, "message": { "mid": "mid.$cAAKEShkF7FJhk-NellbYp4VzAIdE", "seq": 105605, "text": "hahaha" } } ] } ]}

Send messages

Install an additional requirement:

$ pip3 install requests

Send text function

import requests

PAGE_TOKEN = "your-page-access-token"FB_MESSENGER_URI = "https://graph.facebook.com/v2.6/me/messages?access_token=" + PAGE_TOKEN

def send_text(reply_token, text): data = { "recipient": {"id": reply_token}, "message": {"text": text} } r = requests.post(FB_MESSENGER_URI, json=data) if r.status_code != requests.codes.ok: print(r.content)

Return messages to a user

def fb_post_handler(req): print req.get_data() resp_body = req.get_json()

for entry in resp_body["entry"]: for msg in entry["messaging"]: sender = msg['sender']['id'] if 'message' in msg: if msg['message'].get('is_echo'): return "" if 'text' not in msg[‘message']: return "" text = msg['message']['text'] send_text(sender, text) return ""

Test - talk to you bot again

Messenger Profile

Facebook provides some API call for us to configure the BOT environment

•Greeting - A help message to show a user what the purpose of the bot is

•Get Started - Setup the postback message when a user is first login

•Persistent Menu

Messenger Profile API

POST

https://graph.facebook.com/v2.6/me/messenger_profile?access_token=<your-page-access-token>

A JSON body for the configurations

Greeting

curl -X POST \ 'https://graph.facebook.com/v2.6/me/messenger_profile?access_token=<your-page-access-token>' \ -H 'content-type: application/json' \ -d '{ "greeting":[ { "locale":"default", "text":"嗨，我會幫你查匯率"

} ] }'

Get Started

curl -X POST \ 'https://graph.facebook.com/v2.6/me/messenger_profile?access_token=<your-page-access-token>' \ -H 'content-type: application/json' \ -d '{ "get_started":{ "payload":"GET_STARTED" }}'

POSTBACK

Some user-defined words which represents some kinds of events have been triggered.

For example, once a new user starts chatting with the bot, a predefined postback message will sent to your server.

Payload{ "object": "page", "entry": [ { "id": "708403975999401", "time": 1492364568758, "messaging": [ { "recipient": { "id": "708403975999401" }, "timestamp": 1492364568758, "sender": { "id": "1433303610077218" }, "postback": { "payload": "GET_STARTED" } } ] } ]}

Handle the POSTBACK

def fb_post_handler(req): print req.get_data() resp_body = req.get_json()

for entry in resp_body["entry"]: for msg in entry["messaging"]: sender = msg['sender']['id'] if 'message' in msg: if msg['message'].get('is_echo'): return "" text = msg['message']['text'] send_text(sender, text) elif 'postback' in msg: if msg['postback']['payload'] == "GET_STARTED": send_text(sender, 'welcome') return ""

Send More

Generic Template

Generic template is some FB predefined rich message format.

Lists, Images, Buttons

Generic Template{ "message": { "attachment": { "type": "template", "payload": { "template_type": "generic", "elements": [ { "title": "BTC - USD", "image_url": "<image url>", "subtitle": "The currency between BTC and USD" } ] } } }}

Image

{ "title": "BTC - USD", "image_url": "<image url>", "subtitle": "The currency between BTC and USD"}

Send Template Functiondef send_template_message(user_id, elements): data = { "recipient":{ "id": user_id }, "message":{ "attachment": { "type":"template", "payload":{ "template_type":"generic", "elements": elements } } } }

r = requests.post(FB_MESSENGER_URI, json=data) if r.status_code != requests.codes.ok: print(r.content)

def fb_post_handler(req): . . . for entry in resp_body["entry"]: for msg in entry["messaging"]: sender = msg['sender']['id'] if 'message' in msg: . . . text = msg['message']['text'] if text == "btcusd": element = [{ "title":"<title>", "image_url":"<url>", "subtitle":"<sub title>" }] send_template_message(sender, element) else: send_text(sender, text) elif 'postback' in msg: . . .

Button Types

web_url - an url link

postback - some customized events

Etc.

Image with URL Button{ "title": "BTC - USD", "image_url": "<image url>", "subtitle": "The currency between BTC and USD", "buttons": [ { "type": "web_url", "url": "https://btc-e.com/exchange/btc_usd", "title": "View in BTC-E“ } ]}

if 'message' in msg: . . . text = msg['message']['text'] if text == "btcusd": element = [{ "title":"<title>", "image_url":"<url>", "subtitle":"<sub title>", "buttons": [ {"type": "web_url", "url": "https://btc-e.com/exchange/btc_usd", "title": "View in BTC-E" } ] }] send_template_message(sender, element) else: send_text(sender, text) elif 'postback' in msg: . . .

Image with POSTBACK Button

{ "title": "BTC - USD", "image_url": "<image url>", "subtitle": "The currency between BTC and USD", "buttons": [ { "type": "postback", "payload": "HAHAHA", "title": "Laugh" } ]}

def fb_post_handler(req): . . . element = [{ . . . "buttons": [ {"type": "web_url", "url": "", "title": "View in BTC-E" }, {"type": "postback", "payload": "HAHAHA", "title": "Laugh" } ] }] . . . if msg['postback']['payload'] == "GET_STARTED": send_text(sender, 'welcome') elif msg['postback']['payload'] == "HAHAHA": send_text(sender, 'hahaha!') . . .

Ask a question

FB can also send some quick answers for a user to select

This is called: quick-replies

Quick Replies

"message":{ "text":"Query currency?”, "quick_replies":[ { "content_type":"text", "title":"Yes", "payload":"YES" }, { "content_type":"text", "title":"No", "payload":"NO", } ]}

Extend our send_text function

def send_text(reply_token, text, answers): data = { "recipient": {"id": reply_token}, "message": {"text": text} } if answers: data["message"]["quick_replies"] = answers r = requests.post(FB_MESSENGER_URI, json=data) if r.status_code != requests.codes.ok: print(r.content)

def fb_post_handler(req): . . .

send_text(sender, text, None) . . .

Send quick replies

. . .elif text == "btcusd": . . .

elif text == "Btc": send_text(sender, "Query currency?", [ {"content_type":"text", "title":"Yes", "payload":"QUERY_CURRENCY" }, {"content_type":"text", "title":"No", "payload":"CANCEL" } ]) . . .

Payload{ "object": "page", "entry": [ { "id": "708403975999401", "time": 1492411242498, "messaging": [ { "sender": { "id": "1433303610077218" }, "recipient": { "id": "708403975999401" }, "timestamp": 1492411242366, "message": { "quick_reply": { "payload": "CANCEL" }, "mid": "mid.$cAAKEShkF7FJhq-mfflbeqRWhUtKd", "seq": 106589, "text": "No" } } ] } ]}

Handle quick replies response

. . .

if 'message' in msg: if msg['message'].get('is_echo'): return "" if 'text' not in msg['message']: return "" if 'quick_reply' in msg['message']: reply = msg["message"]["quick_reply"] if reply['payload'] == "QUERY_CURRENCY": send_text(sender, "This function is not worked yet.", None) elif reply['payload'] == "CANCEL": send_text(sender, "No problem.", None) return "" text = msg['message']['text'] if text == “btcusd":

. . .

Review

Go back to developer page

Submit a review

Make a video

Not mentioned

Location

Persistent menu

Lots of advanced features

Reference

http://flask.pocoo.org/

https://developers.facebook.com/docs/messenger-platform

http://docs.python-requests.org/en/master/

Q & A