Get Started with Voice Notifications using .NET

    Overview

    You can send an audio notification to the user using Voice Calls. Plivo allows you to quickly create and configure a voice alert system for your business. An API call from your application will trigger the PHLO/API and will enable making direct calls to the customers with critical alerts.

    Start your Voice Notifications implementation with Plivousing PHLO or the traditional API/XML way. PHLO allows you to create and deploy the call flows using its intuitive canvas in few clicks. Refer to the instructions from the respective tabs below to start your integration with PHLO or XML as you wish.

    To implement voice notifications use-case, you can create and deploy a PHLO with a few clicks on the PHLO canvas. PHLO also lets you visually construct your entire use-case. With PHLO, you only pay for calls you make/receive, and building with PHLO is free.

    Outline

    Implementation

    In this section, we will guide you to create a PHLO to implement voice notifications use-case.

    Prerequisites

    1. Create a Plivo Account(if you don’t have one already): You can sign up with your work email address and complete the phone verification step using your mobile number.
    2. Set up your Dotnet dev environment: To set up your dev environment in your .NET(C#) programming language, please refer to the instructions available in the Set up Your Dotnet Dev Environment section.
    3. Buy a Plivo number(optional): You must have a voice-enabled Plivo phone number if you are willing to receive incoming calls. You can purchase numbers from the Numbers section of your Plivo Console. It is also possible to purchase numbers using the Numbers API.

    Create the PHLO

    • On the top navigation bar, click PHLO. The PHLO page will appear and display your existing PHLOs, if any exist. If this is your first PHLO, then the PHLO page will be empty.

      Console Top Nav Bar

    • Click CREATE NEW PHLO to build a new PHLO.

      Console Create New PHLO

    • On the Choose your use-case window, click Build my own. The PHLO canvas will appear with the Start node. Note: The Start node is the starting point of any PHLO. You can choose between the four available trigger states of the Start node; Incoming SMS, Incoming Call, and API Request. For this PHLO, we will use the API Request trigger state.
    • Click the Start node to open the Configurations tab.
    • Then, enter the information to retrieve from the HTTP Request payload. For example, this could be a variable for the list of numbers to call.

    • From the list of components on the left-hand side, drag and drop the Initiate Call component onto the canvas. This will add a Initiate call node onto the canvas.

    • Connect the Start node with the Initiate Call node, using the API Request trigger state.

    • The values for the From and To numbers are picked from the HTTP Request Payload. Make sure to clearly define the variables in the Start node.

    • Next, to configure the From and To numbers in the Initiate Call node, use the variables set in the Start node. Note:

      • Enter two curly brackets to view all available variables.
      • The values for the From and To numbers are picked from the HTTP Request Payload. Make sure to clearly define the variables in the Start node.

    • Similarly, create a node for the Play Audio component and connect it to the Initiate Call node using the Answered trigger state.

    • Next, configure the Play Audio node to play a specific message to the user.

      Note:

      • The audio playback can either be static or dynamic. In this example, we will use a combination of a static message along with some dynamic message.
      • On the Play Audio Configurations tab, enter a static message (For example, Your Flight status is:) in the Speak Text field, followed by a variable to include the dynamic text.
    Note:
    • You can choose a variable by entering two curly brackets in the Speak Text field.
    • Make sure you validate the configuration for each node.
    • After you complete the configurations, click Save. You can trigger your PHLO using the PHLO URL to test it out. Your complete PHLO will look like this:

      Voice Notification

    Set up Your Dotnet Dev Environment

    You must set up and install Dotnet Framework(.NET Framework 4.6 or higher) and Plivo’s Dotnet SDK to implement voice notifications use-case. Here’s how.

    Install Dotnet Framework

    Operating SystemInstructions
    OS X & LinuxYou would already have Dotnet Framework installed, you can check this by running the command dotnet --version in the terminal. If you do not have it installed, you can install it from here.
    WindowsTo install Dotnet Framework on Windows you can follow the instructions from here.

    Install Plivo .NET Nuget Package using Visual Studio

    • Create a new project in Visual Studio

      Create New Project

    • Choose a Template for the new project

      Choose Template

    • Install the Plivo Nuget package

      Manage Nuget packages Select Plivo Nuget package

    Trigger the PHLO

    Once you have created and setup your Dotnet dev envrironment, you can go to your Plivo Consolse and copy the PHLO_ID. You can integrate a PHLO into your application workflow by making an API request to trigger the PHLO with the required payload.

    With Static Payload

    You can choose to either configure the mandatory params required for a PHLO while creating the PHLO itself or, you can pass the params as payload while triggering the PHLO from your app.

    Note: When you configure the params while creating the PHLO, the values are hardcoded, and they act as static payload.

    With Static Payload

    Code

    Now, open the file in the CS project called Program.cs and paste the below code.

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    using System;
    using Plivo;
    
    namespace test_PHLO
    {
        class Program
        {
            public static void Main(string[] args)
            {
                var phloClient = new PhloApi("auth_id", "auth_token"); 
                var phloID = "phlo_id"; // replace the placeholder phlo_id with your PHLO_ID from Plivo Console
                var phlo = phloClient.Phlo.Get(phloID);   
                Console.WriteLine(phlo.Run());
            }
        }
    }
    

    With Dynamic Payload

    To use dynamic values for the parameters, you can use the liquid templating params while creating the PHLO and pass the values while triggering the PHLO.

    With Dynamic Payload

    Code

    Now, open the file in the CS project called Program.cs and paste the below code.

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    using System;
    using System.Collections.Generic;
    using Plivo;
    
    namespace test_PHLO
    {
        class Program
        {
            public static void Main(string[] args)
            {
                var phloClient = new PhloApi("auth_id", "auth_token");
                var phloID = "phlo_id"; // replace the placeholder phlo_id with your PHLO_ID from Plivo Console
                var phlo = phloClient.Phlo.Get(phloID); 
                var data = new Dictionary<string, object>
                {
                    { "from", "+14157778888" },
                    { "to", "+14157778889" }
    
                };  
                Console.WriteLine(phlo.Run(data));
            }
        }
    }
    

    You can get your Auth_ID and Auth_token from your dashboard AUTHID

    You can find the PHLO_ID on the PHLO Listing page. PHLO Listing

    Test and Validate

    You can save the file and run it.

    Note: If you are using a Plivo Trial account for this example, you can only make calls to phone numbers that have been verified with Plivo. Phone numbers can be verified at the Sandbox Numbers page.

    To implement voice notifications in the traditional API/XML way, you can refer to the instructions in the below section to begin your implementation.

    Outline

    Outbound- Call Flow

    Implementation

    In this section, we will guide you in setting up an app using Plivo’s API/XML to implement voice notifications. First, let’s make sure you meet these prerequisites before we dive into the code.

    Prerequisites

    This section will guide you through how to use Plivo APIs to make voice calls from your application. First, let’s make sure you meet these prerequisites before we dive into the code.

    • Plivo Auth Id and Auth Token: You will find your Plivo Auth Id and Auth Token on the home screen of your Plivo Console. Click here to sign-up for a Plivo account if you haven’t already!

      credentials

    • Plivo Phone Number(Optional): You can purchase numbers from the Numbers section of your Plivo Console and use the same as the caller ID for the outbound call. This number will also help you receive incoming calls as you must have a voice-enabled Plivo phone number to do the same. Please note that you can also purchase numbers using the Numbers API.

      Buy New Number

    • Answer Url: When a call is answered by the destination_number, you can control the call flow with the help of the answer_url set in the API request. Plivo will invoke the answer_url specified as soon as the call is answered and expect a valid XML response with instructions to handle the call. For example, you can use https://s3.amazonaws.com/static.plivo.com/notification.xml as answer_url to test voice notification implementation. The XML response of this is:

      <Response>
      <Speak>Congratulations! Your order has been successfully placed!</Speak>
      </Response>
      

      As you can tell, the XML above holds instructions to say ‘Congratulations! Your order has been successfully placed!’ to the callee. You can find the entire list of Plivo XML verbs and their details in the XML Reference section of the website here.

    Set up Your Dotnet Dev Environment

    You must set up and install Dotnet Framework(.NET Framework 4.6 or higher) and Plivo’s Dotnet SDK to implement voice notifications use-case. Here’s how.

    Install Dotnet Framework

    Operating SystemInstructions
    OS X & LinuxYou would already have Dotnet Framework installed, you can check this by running the command dotnet --version in the terminal. If you do not have it installed, you can install it from here.
    WindowsTo install Dotnet Framework on Windows you can follow the instructions from here.

    Install Plivo .NET Nuget Package using Visual Studio

    • Create a new project in Visual Studio

      Create New Project

    • Choose a Template for the new project

      Choose Template

    • Install the Plivo Nuget package

      Manage Nuget packages Select Plivo Nuget package

    Create the Voice Notifications App

    Once you have the above prerequisites set, You can follow the below instructions to create an app to make an outbound call and leave a text-to-speech message(as Voice Notification) once the call recipient answers the call.

    Now, open the file in the CS project called Program.cs and paste the below code.

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    using System;
    using System.Collections.Generic;
    using Plivo;
    
    namespace testplivo
    {
        class Program
        {
            static void Main(string[] args)
            {
                var api = new PlivoApi("YOUR_AUTH_ID", "YOUR_AUTH_TOKEN");
                var response = api.Call.Create(
                    to: new List<String> { "the_destination_number" },
                    from: "the_callerID",
                    answerMethod: "GET",
                    answerUrl: "https://s3.amazonaws.com/static.plivo.com/notification.xml"
                );
                Console.WriteLine(response);
            }
        }
    }
    
    Note:
    • Replace the placeholders auth_id & auth_token with your credentials from Plivo Console.
    • We recommend that you store your credentials in the auth_id & auth_token environment variables, so as to avoid the possibility of accidentally committing them to source control. If you do this, you can initialize the client with no arguments and it will automatically fetch them from the environment variables
    • You can use Environment.SetEnvironmentVariable Method to store environment variables and fetch them using Environment.GetEnvironmentVariable Method while initializing the client.
    • Replace the placeholder the_callerID with the Phone number which you have purchased and the_destination_number with the phone number you will be making calls to.
    • Both plivo_source_number and the_destination_number should be in E.164 format, for example +15671234567.

    Test and Validate

    Once you have created the Voice Notifications App, Save the file and run it.

    Make outbound call

    Note: If you are using a Plivo Trial account for this example, you can only make calls to phone numbers that have been verified with Plivo. Phone numbers can be verified at the Sandbox Numbers page.

    Common Use Cases for Voice Notifications

    You can also use this PHLO structure for other use cases, like:

    • Order notification
    • Booking status
    • Delivery status
    • Flight cancellation/reschedule
    • Two-Factor Authentication/One-Time Password
    • New Offer notification
    • Account balance notification