Call transfer using Flask and Bandwidth-SDK

call_transfer.py

# Example was written with ngrok.io, flask, and bandwidth-sdk
# Pre Reqs:
#   pip install flask (http://flask.pocoo.org/)
#   pip install bandwidth_sdk (https://github.com/bandwidthcom/python-bandwidth)
# To use:
# Step 1: Order a phone number and assign that to a catapult application with autoanswer
# Step 2: Set the callback URL to POST and the ngrok url (IE: http://eb111111.ngrok.io/callback)
# Step 3: Fill in your information for Catapult ID, Token, Secret
# Step 4: Fill in your information for 'transfer number'
# Step 5: Launch the app: python call_transfer.py
# Step 6: Call the number ordered in step 1
# Step 7: Notice that the number set in Step 4 will ring with caller_id set to Bandwidth #
# Step 8: Talk!
# Step 9: Profit
import json
from flask import Flask, request
from bandwidth_sdk import Client, AnswerCallEvent, Call, Event
app = Flask(__name__)

# SERVER_NAME should be the ngrok URL WITHOUT http:// or port
# The name and port number of the server
SERVER_NAME = 'eb111111.ngrok.io' # SAMPLE ngrok SEVER_NAME

# Set to true to enable web debugging.  Be careful as this feature will dump
# stack traces that may contain sensitive data when errors happen.
DEBUG = True

# Your Catapult API User
CATAPULT_USER_ID = 'u-asdtlaksdgjioe9253829i5' # SAMPLE USER_ID

# Your Catapult API Token
CATAPULT_API_TOKEN = 't-kelkasdf5riaokuoxenr5232' # SAMPLE API_TOKEN

# Your Catapult API Secret
CATAPULT_API_SECRET = 'j35239sna3ub2sapwe69scs3pudp4cz2qqtozry' # SAMPLE SECRET

# Hard coded example number, this is the number that will ring
# Transfer Number
TRANSFER_NUMBER = '+12223334444'


# Initialize bandwidth sdk with your credentials
Client(CATAPULT_USER_ID,
       CATAPULT_API_TOKEN,
       CATAPULT_API_SECRET)

# Note that the Callback URL will be POST to http://eb111111.ngrok.io/callback
@app.route('/callback', methods=['POST'])
def callback():
    """
    Route a catapult callback to the appropriate handler.  These functions
    control call flow.
    :return:
    """
    # process the event
    event = Event.create(**request.json)
    app.logger.debug('received callback event: %s' % event)
    if isinstance(event, AnswerCallEvent):
        transfer_call(event)
    else:
        app.logger.debug('event unhandled: %s' % event)

    return 'ok'


def transfer_call(event):
    """
    transfers an answered call event.
    :param event:
    :return:
    """

    call = Call.get(event.call_id)
    # Will set the caller ID to the Bandwidth Number, thus masking the original caller's phone number
    call.transfer(TRANSFER_NUMBER, transfer_caller_id=event.to)

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