The Messenger class (defined in Messenger.py) encapsulates all API calls in a single class. It provides functions such as send_xyz (send_message, send_attachment etc.) and several ways to listen for incoming messages.

Create a file called echo_bot.py. Then, open the file and create an instance of the Messenger class.

from pynani import Messenger

PAGE_ACCESS_TOKEN = 'EAAxxxxxxx...'
mess = Messenger(PAGE_ACCESS_TOKEN)

[!IMPORTANT] Make sure to actually replace PAGE_ACCESS_TOKEN with your own page access token.

After that declaration, we need to register some message handlers. First, we need to create and verify a webhook with the help of Flask or FastAPI.

from flask import Flask, request, jsonify

app = Flask(__name__)

TOKEN = "abc123"

@app.get("/")
def meta_verify():
    return mess.verify_token(request.args, TOKEN)

Now let's define a webhook that handles certain messages

@app.post("/")
def meta_webhook():
    data = request.get_json()
    sender_id = mess.get_sender_id(data)
    message = mess.get_message_text(data)
    if message == "Hello":
        mess.send_text_message(sender_id, "Hello, World!")
    if message == "Bye":
        mess.send_text_message(sender_id, "Nice to meet you! 👍🏽")

    return jsonify({"status": "success"}), 200

We now have a basic bot which replies a static message to "hello" and "bye" messages. To start the bot, add the following to our source file:

if __name__ =='__main__':
    app.run(port=8080, debug=True)

Alright, that's it! Our source file now looks like this:

from flask import Flask, request, jsonify
from pynani import Messenger

PAGE_ACCESS_TOKEN = 'EAAxxxxxxx...'
TOKEN = "abc123"

mess = Messenger(PAGE_ACCESS_TOKEN)
app = Flask(__name__)

@app.get("/")
def meta_verify():
    return mess.verify_token(request.args, TOKEN)

@app.post("/")
def meta_webhook():
    data = request.get_json()
    sender_id = mess.get_sender_id(data)
    message = mess.get_message_text(data)
    if message == "Hello":
        mess.send_text_message(sender_id, "Hello, World!")
    if message == "Bye":
        mess.send_text_message(sender_id, "Nice to meet you! 👍🏽")

    return jsonify({"status": "success"}), 200

if __name__ =='__main__':
    app.run(port=8080, debug=True)