How To Voice Call From Web To Mobile In Angular Using C# .NET Core And Twilio

In this blog, We are going to learn How To Voice Call From Web To Mobile In Angular Using C# .NET Core.

First of all, We need Twilio credentials to move forward. Please get it from the Twilio console by yourself.

We need the below Keys to move forward.

• Account SID
• AUTH TOKEN
• PHONE NUMBER (TWILLIO PHONE NUMBER)

We need twillio APIKey and APISecret to integrate the Call API, You can generate it from here.

Now you need to create a TwiML  App, which will help you to voice call.

Now you need to add REQUEST URL in TwiML app, so you need to create one public URL to move forward.(Note: Local URLs will not work) and then need to set in below format.

<your-ngrok-public-url>/<your-method-path>

Now, we have all the required keys, Let’s get start coding.

As I am using Angular, I need to create one API project to manage API stuff.

So, now I am creating a .NET Core API project.

 1) .NET Core API

Install the Twilio from the Package manager Console For Twilio Package

Install-Package Twilio

And Also, Twilio.AspNet.Core.

Install-Package Twilio.AspNet.Core -Version 5.37.2

Create a TokenController to get token:

using Microsoft.AspNetCore.Mvc;
using Twilio.Jwt.AccessToken;
using System.Collections.Generic;
using Twilio.AspNet.Core;

namespace Angular_API.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class TokenController : TwilioController
    {
        
        [HttpGet("token")]
        public string GetTwilioToken()
        {

            var twilioAccountSid = "ACXXXXXXXXXXXXXXXXXXXXXXXX";
            var appSid = "APXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
            var twilioApiKey = "SKXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
            var twilioApiSecret = "xxxxxxxxxxxxxxxxxxxxxxxxxx";

            var grant = new VoiceGrant();
            grant.OutgoingApplicationSid = appSid;

            grant.IncomingAllow = true;

            var grants = new HashSet<IGrant>
            {
                { grant }
            };
            string role = "user"; //Default role

            var accessToken = new Token(
                twilioAccountSid,
                twilioApiKey,
                twilioApiSecret,
                role,
                grants: grants);

            return accessToken.ToJwt();
        }
    }
}

Now, Need to create one more method which is we provide to the TwiML App Request URL.

Syntex:

using Microsoft.AspNetCore.Mvc;
using Twilio.TwiML;
using Twilio.AspNet.Core;
using Twilio.TwiML.Voice;

namespace Angular_API.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class CallController : TwilioController
    {
        // POST Call/Connect
        [HttpPost("Connect")]
        public TwiMLResult Connect()
        {
            string toNumber = Request.Form["phoneNumber"].ToString();
            const string PhoneNumber = "+11111111111";

            var response = new VoiceResponse();

            var dial = new Dial(callerId: PhoneNumber);

            dial.Number(toNumber);
            response.Append(dial);

            return TwiML(response);
        }
    }
}

Our API is ready to use.

Now let’s create the frontend (web page).

 2)  Angular App

Create an Angular app.

1. call.component.html file:

   <div class="row">
     <div class="col-md-6">
       <input
         type="email"
         id="phone"
         class="form-control form-control-alternative"
         name="message"
         [(ngModel)]="phoneNumber"
         required
         #fullname="ngModel"
         placeholder="Mobile Number"
      />
     </div>
     <div class="col-md-3" *ngIf="callHideShow === true">
       <button
         type="button"
         class="btn btn-primary my-4"
         (click)="callCustomer()" >
         Call
       </button>
     </div>
     <div class="col-md-3" *ngIf="stopHideShow === true">
       <button
         type="button"
         class="btn btn-dark my-4"
         (click)="Stop()">
           Stop
       </button>
     </div>
   </div>

2. call.component.ts file:

   import { HttpClient } from '@angular/common/http';
   import { Component, OnInit, ViewChild } from '@angular/core';
   import { NgForm } from '@angular/forms';
   declare const Twilio: any;
   
   @Component({
     selector: 'app-voicecall',
     templateUrl: './voicecall.component.html',
     styleUrls: ['./voicecall.component.css']
   })
   export class VoicecallComponent implements OnInit {
     phoneNumber: any;
     connection: any = null;
     device: any;
     callHideShow: any = true;
     stopHideShow: any = false;
   
     constructor(public http: HttpClient) { }
   
     ngOnInit(): void {
       this.http.get('https:/879875454.ngrok.io/api/Browser/token',  { responseType: 'text'}).subscribe((data)=>
      {
          console.log(data);
          this.device = Twilio.Device.setup(data);
          this.setupHandlers(this.device);
          console.log(this.device);
      });
     }
   
     setupHandlers(device) {
       device.on('ready', (_device) => {
           this.updateCallStatus("Ready to call");
       });
   
       device.on('error',  (error) => {
           this.updateCallStatus("ERROR: " + error.message);
       });
   
       device.on('connect', (connection) => {
           if ("phoneNumber" in connection.message) {
               this.updateCallStatus("In call with " + connection.message.phoneNumber);
               this.callHideShow = false;
               this.stopHideShow = true;
           } else {
               this.updateCallStatus("In call with support");
           }
       });
   
       device.on('disconnect',  (connection) => {
           this.updateCallStatus("Call End");
           this.stopHideShow = false;
           this.callHideShow = true;
       });
     }
   
     updateCallStatus(status: string): void {
       console.log("Status -> ",  this.callStatusList)
     }
   
     callCustomer(){
       if (!this.form.valid) {
         return;
       }
   
       this.updateCallStatus("Calling " + this.phoneNumber + "...");
   
       var params = { "phoneNumber": this.phoneNumber };
       this.device.connect(params);
       this.form.reset();
     }
   
     Stop(){
       this.device.disconnectAll();
       this.stopHideShow = false;
       this.callHideShow = true;
     }
   
   }
   

3. Index.html

• Add Twilio Client CDN.

  <script type="text/javascript" src="https://sdk.twilio.com/js/client/v1.13/twilio.min.js"></script>

OUTPUT:

That’s It.

Let me know if you face any difficulties.