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Dial a chip tune

So I was hacking around with Nexmo and needed a little bit of light relief. I've been listening to quite a lot of chiptune music recently, so decided to do something that combined Nexmo and my love of chiptunes. Dial-a-chiptune was the result. It's not meant to be a serious project - but it could be. You could take the basic idea and some of the code I describe here, and develop a much more ambitious project, such as a full-blown Interactive Voice Response system.

The basics

So the idea is you dial a Nexmo number, select an option, and you get to hear a chiptune. Simple. Nexmo makes doing things like this relatively easy.

The code

Here's the full code. You have to have a Nexmo Number, configure your webhooks and deploy to your web server (or use Ngrok). I have covered all these topics in previous articles so I am going to assume you know how to do all of those things already.

#!/usr/bin/env python3
from flask import Flask, request, jsonify
from pprint import pprint

app = Flask(__name__)

tune_1 = ["https://raw.githubusercontent.com/tbedford/git-testing-repo/master/tunes/Komiku_Sunset_on_the_beach.mp3"]
tune_2 = ["https://raw.githubusercontent.com/tbedford/git-testing-repo/master/tunes/Rushjet1_Azureflux_Remix.mp3"]
tune_3 = ["https://raw.githubusercontent.com/tbedford/git-testing-repo/master/tunes/Kris_Keyser_Only.mp3"]

def answer_call():
    params = request.args
    print("DIAL_A_CHIP_TUNE CALL FROM: >%s<" % params['from'])
    input_webhook_url = request.url_root + "webhooks/dtmf"
    ncco = [
            "action": "talk",
            "text": "Welcome to dial a chiptune. Press 1 or 2."
            "action": "input",
            "maxDigits": 1,
            "timeOut": 5,
            "eventUrl": [input_webhook_url]
    return jsonify(ncco)

@app.route("/webhooks/dtmf", methods=['POST'])
def dtmf_webhook():
    data = request.get_json()
    selection = data['dtmf']
    print("TUNE SELECTED = %s" % selection)
    MESSAGE = "Playing tune " + selection
    if selection == "1":
        #print("DEBUG: Selecting tune 1")
        tune_x = tune_1
    elif selection == "2":
        tune_x = tune_2
        tune_x = tune_3 

    ncco = [
            "action": "talk",
            "text": MESSAGE
            "action": "stream",
            "streamUrl": tune_x
    return jsonify(ncco)

if __name__ == '__main__':
    app.run(host="www.fuddyduddies.org", port=9000)

A few points about the code:

Hopefully mostly the code is self-explanatory. The Flask app mostly provides the webhook implementation with the main control being done by the NCCOs. Contact me if you have any questions on the code, or something is really not clear.

Testing the code

Couldn't be easier. Simply dial the Nexmo Number you linked to your Nexmo Application and select 1, 2 or actually any other digit key. You will then receive confirmation of your selection before hearing a chiptune. Sure the quality of the sound is not great - this is a phone line with limited bandwidth after all, but that's not the important thing here. The point is you have a basic IVR application. You can extend this to suit your own projects.


This has been a fun little hack and actually my first Flask application. You saw how to build a simple IVR application using Nexmo webhooks and Nexmo Call Control Objects (NCCOs).