This ASP.NET MVC sample application is modeled after a typical call center experience with an IVR, but with more Reese's Pieces.
Stranded aliens can call a phone number and receive instructions on how to get out of earth safely, or call their home planet directly. In this tutorial, we'll show you the key bits of code to make this work.
To initiate the phone tree, we need to configure one of our Twilio numbers to send our web application an HTTP request when we get an incoming call.
Click on one of your numbers and configure the Voice URL to point to our app. In our code the route will be /ivr/welcome.
If you don't already have a server configured to use as your webhook, ngrok is a great tool for testing webhooks locally.
With our Twilio number configured, we are prepared to respond to the Twilio request.
Respond to the Twilio request with TwiML
Our Twilio number is now configured to send HTTP requests to this controller on any incoming voice calls. Our app responds with TwiML to tell Twilio what to do in response to the message.
In this case we tell Twilio to Gather the input from the caller and we Say a welcome message.
Respond with TwiML to gather an option from the caller
gather.Say("Thank you for calling the E.T. Phone Home Service - the "+
23
"adventurous alien's first choice in intergalactic travel. "+
24
"Press 1 for directions, press 2 to make a call.");
25
response.Append(gather);
26
27
returnTwiML(response);
28
}
29
}
30
}
After reading the text to the caller and retrieving their input, Twilio will send this input to our application.
Where to send the caller's input
The gather'saction parameter takes an absolute or relative URL as a value - in our case, the /menu/show route.
When the caller has finished entering digits, Twilio will make a GET or POST request to this URL including a Digits parameter with the number our caller chose.
After making this request, Twilio will continue the current call using the TwiML received in your response. Any TwiML verbs occuring after a <Gather> are unreachable, unless the caller enters no digits.
gather.Say("Thank you for calling the E.T. Phone Home Service - the "+
23
"adventurous alien's first choice in intergalactic travel. "+
24
"Press 1 for directions, press 2 to make a call.");
25
response.Append(gather);
26
27
returnTwiML(response);
28
}
29
}
30
}
Now that we have told Twilio where to send the caller's input, we can look at how to process that input.
The Main Menu: Process the caller's selection
This route handles processing the caller's input.
If our caller chooses 1 for directions, we use the helper method ReturnInstructions to respond with TwiML that will Say directions to our caller's extraction point.
If the caller chooses 2 to call their home planet, we need to gather more input from them. We'll cover this in the next step.
If the caller enters anything else we respond with a TwiML Redirect to the main menu.
That was only the main menu and the first option. If the caller chooses 2, we will take them to The Planet Directory in order to collect more input.
The Planet Directory: Collect more input from the caller
If our callers choose to call their home planet we will give them the planet directory. This is akin to a typical "company directory" feature of most IVRs.
In our TwiML response we again use a Gather verb to receive our caller's input. This time, the action verb points to the planets route, which will switch our response based on what the caller chooses.
Collect more input from the caller via the Planet Directory
Again we show some options to the caller and instruct Twilio to collect the caller's choice.
The Planet Directory: Connect the caller to another number
In this route, we grab the caller's selection off the request and store it in a variable called userOption. We then use a Dial verb with the appropriate phone number to connect our caller to their home planet.
The current numbers are hardcoded, but they could also be read from a database or from a file.
Instantly collect structured data from your users with a survey conducted over a voice call or SMS text messages. Learn how to create your own survey in ASP.NET MVC.