Get Started with Number Masking using Ruby

    Overview

    Phone number masking is the process of establishing a call between two parties without revealing their contact information. Many businesses often require a technique to anonymize communication between two parties involved on the platform, for example, a customer and a delivery agent on a food delivery service platform. This technique involves an intermediate phone number that acts as a proxy between the two parties on the call. In this guide, we will walk you through the implementation of number masking with the help of a Plivo number which will act as the intermediate number to connect both the parties on a call anonymously.

    Outline

    Implementation

    In this example, we will build a number masking application for a food delivery service. Through this implementation, the company can connect the customers with the delivery agents and vice versa without revealing their actual phone numbers.

    Following are the steps involved in the implementation phase:

    1. Create a Customer<->Agent phone number mapping in your application backend
    2. Create the number masking application using the Plivo Voice platform.
    3. Assign the number masking app to a Plivo number.

    Set Up Your Ruby on Rails Dev Environment

    You must install rails, create a rails project and add Plivo’s Ruby SDK to make your first call. Here’s how.

    Install Rails

    Use the below command to install Rails

    $ gem install rails
    

    Create a Rails Project

    As we have Rails and its dependencies installed, we can use them to create a new Rails project. As the initial step, using rails we can auto-generate code in the ruby on rails folder structure. Use the below command to start your Rails project.

    $ rails new numbermasking
    

    This will create a numbermasking directory with the necessary folders & files for development.

    Install Plivo

    As we have the rails application created, now, let’s add Plivo-Ruby by modifying the Gemfile. Open the Gemfile in any IDE/text-editor and add the following line:

    gem 'plivo', '~> 4.13.0'
    

    You can use the below command to install the Plivo-Ruby gem into the bundle:

    $ bundle install
    

    Create a 1:1 map with actual numbers

    • Whenever a customer places an order, the customer’s phone number is stored on your app’s database.
    • A delivery executive will be assigned for that order, and the agent’s number is also stored on your database and mapped with the customer’s number. For example,
        Customer's Number		<->		Agent's Number
        1-415-666-7777					1-415-666-7778
      
    • In this guide, we have created a sample mapping data in config/application.rb file like below:
        # customer <> agent map
        config.base_map = {"14156667777" => "14156667778", "14156667779" => "14156667780", "14156667781" => "14156667782"}
      

    Create a Rails Controller for Number Masking

    Change the directory to our newly created project directory, i.e, numbermasking directory and run the below command to create a rails controller for outbound call.

    $ rails generate controller Numbermasking
    

    This will generate a controller named numbermasking_controller in the app/controllers/ directory. Now, You have to open the app/controllers/numbermasking_controller.rb file and add the following code:

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    include Plivo
    
    include Plivo::XML
    include Plivo::Exceptions
    
    # Handle incoming calls to a Plivo number, connect agent with customer and vice versa without revealing their actual phone numbers. 
    class NumbermaskingController < ApplicationController
        def handle_incoming
            customer_agent_map = Rails.application.config.base_map
            agent_customer_map = customer_agent_map.invert
            from_number = params[:From]
            to_number = params[:To]
            response = Response.new()
            customer_to_agent = customer_agent_map.include?(from_number) # To check if the Customer's number is existing in the Customer-Agent mapping
            agent_to_customer = agent_customer_map.include?(from_number) # To check if the Agent's number is existing in the Customer-Agent mapping
            if(customer_to_agent == true)
                dest_number = customer_agent_map[from_number] # This will assign the Value from the customer-agent array to dest_number variable
                params = {
                'callerId' => to_number # Plivo number will be used as the caller ID for the call towards Agent
                }
                dial = response.addDial(params)
                dial.addNumber(dest_number)
            elsif(agent_to_customer == true)
                dest_number = agent_customer_map[from_number] # This will assign the Key from the customer-agent array to dest_number variable
                params = {
                'callerId' => to_number # Plivo number will be used as the caller ID for the call towards Customer
                }
                dial = response.addDial(params)
                dial.addNumber(dest_number)
            end
            xml = PlivoXML.new(response)
            puts xml.to_xml()
            render xml: xml.to_xml
        end
    end
    

    Add a Route

    You need to add a route for the handle_incoming function in NumbermaskingController class, open the config/routes.rb file and add the below line after the outbound route:

    get 'numbermasking/handle_incoming'
    

    Now the numbermasking_controller is ready to handle incoming calls to a Plivo number, connect agent with customer and vice versa without revealing their actual phone numbers. You can use the below command to start the Rails server to forward incoming calls and to handle callbacks.

    $ rails server
    

    And you should see your basic server app in action on http://localhost:3000/numbermasking/handle_incoming/

    Exposing your local server to the internet

    To receive Incoming Calls and to handle callbacks, your local server should be able to connect with Plivo API service, Ngrok is a tunneling software used to expose a web server running on your local machine to the internet. Using Ngrok you can set webhooks which can talk to Plivo server.

    ngrok block diagram

    You can download and install ngrok from here. Follow the detailed configuration instructions to get started.

    Note: Before starting Ngrok service, you need to add ngrok in the config.hosts list in the config/environments/development.rb file and include the below line. You will start facing Blocked host error if you fail to add this.
    # Whitelist Ngrok domain
    config.hosts << /[a-z0-9]+\.ngrok\.io/
    

    Run ngrok on the port which currently hosts your application. For example, if your port number is 3000, run the following command:

    ./ngrok http 3000
    

    This will give you a UI with links that look like ngrok.io/* which you can use to access your local server using the public network.

    Sample ngrok CLI

    • If the incoming call to your Plivo number is from one of the phone numbers of the customer in the Customer <-> Agent Map, for example, if the caller number is “14156667777” then the XML response to process the incoming call will be as below, you can check the XML document in your browser.

      XML Document - Customer Calls Agent

    • If the incoming call to your Plivo number is from one of the phone numbers of the agent in the Customer <-> Agent Map, for example, if the caller number is “14156667778” then the XML response to process the incoming call will be as below, you can check the XML document in your browser.

      XML Document - Agent Calls Customer

    Create a Plivo Application

    1. Create an Application by visiting the Application Page and click on New Application or by using Plivo’s Application API.
    2. Give your application a name. Let’s call it Phone IVR. Enter your server URL (e.g., https://68b9f8c8da2b.ngrok.io/numbermasking/handle_incoming/) in the Answer URL field and set the method as GET. See our Application API docs to learn how to modify your application through our APIs.
    3. Click on Create to save your application.

      Create Application - Number Masking

    Assign a Plivo number to your app

    1. Navigate to the Numbers page and select the phone number you want to use for this app.
    2. Select Phone IVR (name of the app) from the Plivo App dropdown list.
    3. Click on ‘Update Number’ to save.

      Assign Application - Number Masking

    Test and validate

    To test how “Number Masking” works, you need two mobile numbers. You can set one of your mobile numbers as a customer and another one as an agent in the customer: agent mapping data in the config file and make a call to your Plivo phone number. If you call from “mobile number 1” to the Plivo number, you will see that the call is forwarded to your “mobile number2” with the Plivo number as the caller ID. The same setup will work for calls from “mobile number2” to “mobile number1” with the Plivo number as the caller ID.