Making an custom content outbound voice call from console client

Question

I am trying to make an outgoing call using Twilio and C#.

I gave the (fromnumber, tonumber, twiliodemourl) as 3 parameters for initiate outbound call.Then it is working with default twilio demo voice content.

Now i need to customize the voice content attribute and some other attributes every time i trigger the initiate outbound call method

I have gone through Twilio docs i did not find any good option for customize the content dynamically from the code using C# every time i send the request.

My client application running periodically to verify for any new messages and then trigger initiateoutboundcall.

I don't have any custom URL to post any new XML which voice is looking for in 3rd parameter of initiateOutBoundCall.

So is it required a external domain URL to customize the voice content dynamically from code? If no please provide the options/sample i have to do it from C# console application.

I tried to use the twimlets.com to echo the custom text to speak in the call. For text change it is working fine with custom text. But i am not sure whether twimlets.com/echo can be used for production use? Please confirm. Twimlets is not supporting some of the features which i am looking for like Gather input like IVR message for outbound call.

Using Twilio Voice and C# client:

1. Voice Request using Twilio C# client?

   • Dial the number with custom voice content(). If user not responds leave a voice mail with the custom voice content().
   • Dial the number with custom voice content (). If user responds, after reading the message need to provide options like:
     • press 1 for repeat the same voice message.
     • press 2 to confirm the action on the message.
     • press 3 to send SMS for the voice message.

2. Need to get the response for each voice call / message?

   • For the sms it send i am getting response as "queued" instead of message sent. Based on the SMS sent successfully or not i need to update some flag. So how i can get the SMS reponse as "sent".

       SMSMessage sms = twilio.SendSmsMessage(sFromNumber, sToNumber, sMessage);
       Console.WriteLine("SMS Status::::::" + sms.Status);
     

   • Similarly I need the reponse for voice call once the call is ring id done. But it is giving "queued".

       var call = twilio.InitiateOutboundCall(sFromNumber,sToNumber, url);  
       Console.WriteLine("Call Status" + call.Status);
     

So please provide me options for doing it using Twilio.

It would be great if you provide any sample example using C#.

Answer 1

Twilio evangelist here.

You do need some kind of public URL that Twilio can make an HTTP request to once the outbound call is answered. This is how Twilio gets the instructions it needs in order to proceed with the live, in-progress call.

As you noted there are a number of free options for hosting static TwiML content. Twimlets is one. Twimlbin.com is another. Both services are free and great places to at least get started prototyping or setting up a simple MVP of your application, but bear in mind that if you expect a large amount of traffic or you need to build something with your own custom logic in it you'll probably want to move to something else.

That something else could be your own website hosted as as Azure Website (which you can also get for free). Moving to your own website also means that you can scale it as needed and you can start serving up dynamically generated TwiML instead of just being limited to dynamic TwiML as you basically are with Twimlets or Twimlbin.

If you want to process input from <Gather> and none of the Twimlets meet your needs, then you will likely need to look at the Azure option (or some kind of hosted website, doesn't have to be Azure). This will let you build your own custom logic in order to process the callers input and dynamically generate a TwiML response based on that logic.

Twilio provides helper libraries for TwiML generation and for building Twilio apps using ASP.NET MVC, which you can get from NuGet.

Lets say you want to go down the road of building you own custom Twilio app using ASP.NET MVC and hosting it using an Azure Website. In that scenario, using our helper libraries you could build an action method in your controller that returns the TwiML with the <Say> and <Gather> verbs. Something like:

var response = new TwilioResponse();
response.Say("Hello World");
response.BeginGather(new { action="http://example.azurewebsites.com/gather/" } );
response.EndGather();

You would provide the URL that executes that action method as the third parameter in the initiaizeOutboundCall method eg:

client.IntializeOutboundCall(FROM, TO, "http://example.azurewebsites.net");

Once the user enters their input, Twilio will request the URL you specified in the <Gather> verbs action parameter passing you an extra HTTP parameter named Digits, which you can grab in your action method and use in your app logic:

public void Gather(string Digits) {

    var response = new TwilioResponse();
    response.Say("You pressed " + Digits);

    return TwiML(response);
}

To get the status of a phone call or an SMS, you can include use the statuscallback parameter:

• SMS: var result = client.SendMessage(FROM, TO, BODY, "http://example.azurewebsites.net/status");

• Voice: var result = client.InitiateOutboundCall(FROM, TO, VOICEURL, "http://example.azurewebsites.net/status");

Twilio will make HTTP request to the statusCallback URL's once the final status of the message or call is reached.

Hope that helps.

Answer 2

As of version 5.32 of the C# SDK, you can pass a dynamic twiml string into the CallResource.Update() method like so:

CallResource.Update(
   twiml: "<Response><Say>Custom Message Here</Say></Response>"
   pathSid: call.Sid);

Or even:

string customMessage = "<Response><Say>Custom Message Here</Say></Response>"

CallResource.Update(
    twiml: customMessage,
    pathSid: call.Sid);