Create Tasks from Phone Calls using TwiML: Dequeue a Call to a Worker
In the previous step we created a Task from an incoming phone call using <Enqueue workflowSid="WW0123401234..">. In this step we will create another call and dequeue it to an eligible Worker when one becomes available.
Back in Part 1 of the Quickstart, we created a Worker named Alice that is capable of handling both English and Spanish inquiries. With your Workspace open in the TaskRouter web portal, click 'Workers' and click to edit the details of our Worker Alice. Ensure that Alice is set to a non-available Activity state such as 'Offline'. Next, edit Alice's JSON attributes and add a "contact_uri" field. Replace the dummy 555 number below with your own phone number.
Alice's modified JSON attributes:
_10{"languages": ["en", "es"], "contact_uri": "+15555555555"}
Or, as displayed in the web portal:
In this step, we again use <Enqueue> to create a Task from an incoming phone call. When an eligible Worker (in this case Alice) becomes available, TaskRouter will make a request to our Assignment Callback URL. This time, we will respond with a special 'dequeue' instruction; this tells Twilio to call Alice at her 'contact_uri' and bridge to the caller.
For this part of the Quickstart, although not totally necessary it will be useful to have two phones available - one to call your Twilio number, and one to receive a call as Alice. Experienced Twilio users might consider using the Twilio Dev Phone as one of the endpoints.
Before we add the 'dequeue' assignment instruction we need to create a new Activity in our TaskRouter Workspace. One of the nice things about integrating TaskRouter with TwiML is that our Worker will automatically transition through various Activities as the call is assigned, answered and even hung up. We need an Activity for our Worker to transition to when the call ends.
With your Workspace open in the TaskRouter web portal, click 'Activities' and then 'Create Activity'. Give the new Activity a name of 'WrapUp' and a value of 'unavailable'. Once you've saved it, make a note of the Activity Sid:
To return the 'dequeue' assignment instruction, modify Program.cs assignment_callback endpoint to now issue a dequeue instruction, substituting your new WrapUp ActivitySid between the curly braces:
_111using System;_111using System.Net;_111using SimpleWebServer;_111using Twilio;_111using Twilio.Rest.Taskrouter.V1.Workspace;_111using Twilio.Rest.Taskrouter.V1.Workspace.Task;_111using Twilio.TwiML;_111_111namespace taskroutercsharp_111{_111 class MainClass_111 {_111 // Find your Account Sid and Auth Token at twilio.com/user/account_111 const string AccountSid = "{{ account_sid }}";_111 const string AuthToken = "{{ auth_token }}";_111 const string WorkspaceSid = "{{ workspace_sid }}";_111 const string WorkflowSid = "{{ workflow_sid }}";_111_111 public static void Main (string[] args)_111 {_111 // Initialize the Twilio client_111 TwilioClient.Init(AccountSid, AuthToken);_111_111 WebServer ws = new WebServer (SendResponse, "http://localhost:8080/");_111 ws.Run ();_111 Console.WriteLine ("A simple webserver. Press a key to quit.");_111 Console.ReadKey ();_111 ws.Stop ();_111 }_111_111 public static HttpListenerResponse SendResponse(HttpListenerContext ctx)_111 {_111 HttpListenerRequest request = ctx.Request;_111 HttpListenerResponse response = ctx.Response;_111_111 String endpoint = request.RawUrl;_111_111 if (endpoint.EndsWith("assignment_callback")) {_111 response.StatusCode = (int) HttpStatusCode.OK;_111 response.ContentType = "application/json";_111 response.StatusDescription = "{\"instruction\":\"dequeue\", \"from\":\"+15556667777\", \"post_work_activity_sid\":\"WA0123401234...\"}";_111 return response;_111 } else if (endpoint.EndsWith ("create_task")) {_111 response.StatusCode = (int)HttpStatusCode.OK;_111 response.ContentType = "application/json";_111 TaskResource task = TaskResource.Create(_111 WorkspaceSid,_111 attributes: "{\"selected_language\":\"es\"}",_111 workflowSid: WorkflowSid);_111_111 response.StatusDescription = task.Attributes;_111 return response;_111 } else if (endpoint.EndsWith ("accept_reservation")) {_111 response.StatusCode = (int)HttpStatusCode.OK;_111 response.ContentType = "application/json";_111 var taskSid = request.QueryString ["TaskSid"];_111 var reservationSid = request.QueryString ["ReservationSid"];_111 ReservationResource reservation = ReservationResource.Update(_111 WorkspaceSid,_111 taskSid,_111 reservationSid,_111 ReservationResource.StatusEnum.Accepted);_111_111 response.StatusDescription = "{\"reservation_status\":\"" + reservation.ReservationStatus + "\"}";_111 return response;_111 } else if (endpoint.EndsWith ("incoming_call")) {_111 response.StatusCode = (int)HttpStatusCode.OK;_111 response.ContentType = "application/xml";_111 var twiml = new VoiceResponse();_111 twiml.Gather(new Gather(numDigits: 1, action: "enqueue_call")_111 .Say("Para Espanol oprima el uno.", language: "es")_111 .Say("For English, please hold or press two.", language: "en"));_111_111 response.StatusDescription = twiml.ToString();_111 return response;_111 } else if (endpoint.Contains("enqueue_call")) {_111 response.StatusCode = (int)HttpStatusCode.OK;_111 response.ContentType = "application/xml";_111_111 int digitPressed = 0;_111 var language = "";_111 var digitsQuery = request.QueryString["Digits"];_111 if(digitsQuery != null) {_111 try_111 {_111 digitPressed = Int32.Parse(request.QueryString ["Digits"]);_111 } catch (FormatException e)_111 {_111 Console.WriteLine(e.Message);_111 }_111 }_111_111 if (digitPressed == 1) {_111 language = "es";_111 } else {_111 language = "en";_111 }_111_111 var twiml = new VoiceResponse();_111 twiml.Enqueue(_111 "{\"selected_language\":" + language + "\"}", _111 workflowSid: WorkflowSid);_111_111 response.StatusDescription = twiml.ToString();_111 return response;_111 }_111 response.StatusCode = (int) HttpStatusCode.OK;_111 return response;_111 }_111 }_111}
This returns a very simple JSON object from the Assignment Callback URL:
_10{"instruction":"dequeue", "from": "+15556667777", "post_work_activity_sid": "WA01234012340123401234"}
The JSON instructs Twilio to dequeue the waiting call and, because we don't include an explicit "to" field in our JSON, connect it to our Worker at their "contact_uri". This is convenient default behavior provided by TaskRouter.
In the next step, we test our incoming call flow from end-to-end.