Transfer a call

A code snippet that shows how to transfer control of the current call to control by a new NCCO.

Example

Replace the following variables in the example code:

Key	Description
`UUID`	The UUID of the call leg
`NCCO_URL`	The URL of the NCCO to execute. URLs must be array type.

Prerequisites

Modifying an existing call requires that the UUID provided is a currently active call. To modify a call, you must use the same VONAGE_APPLICATION_ID and private key that were used to create the call.

Execute the following command at your terminal prompt to create the JWT for authentication:

export JWT=$(nexmo jwt:generate $PATH_TO_PRIVATE_KEY application_id=$NEXMO_APPLICATION_ID)

Write the code

Add the following to transfer-a-call.sh:

curl -X PUT https://api.nexmo.com/v1/calls/$UUID \
  -H "Authorization: Bearer "$JWT \
  -H "Content-Type: application/json"\
  -d '{"action": "transfer",
      "destination": {"type": "ncco", "url": ["https://developer.nexmo.com/ncco/tts.json"]}}'

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Run your code

Save this file to your machine and run it:

bash transfer-a-call.sh

Prerequisites

npm install @vonage/server-sdk

Create a file named transfer-call.js and add the following code:

const Vonage = require('@vonage/server-sdk');

const vonage = new Vonage({
  apiKey: VONAGE_API_KEY,
  apiSecret: VONAGE_API_SECRET,
  applicationId: VONAGE_APPLICATION_ID,
  privateKey: VONAGE_PRIVATE_KEY
}, { debug: true });

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Write the code

Add the following to transfer-call.js:

const NCCO_URL = "https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json";

vonage.calls.update(UUID, {
  action: 'transfer',
  destination: {
    "type": "ncco",
    "url": [NCCO_URL]
  }
}, (err, res) => {
  if (err) {
    console.error(err);
  } else {
    console.log(res);
  }
});

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Run your code

Save this file to your machine and run it:

node transfer-call.js

Prerequisites

Add the following to `build.gradle`:

compile 'com.vonage:client:6.2.0'

Create a class named TransferCall and add the following code to the main method:

VonageClient client = VonageClient.builder()
        .applicationId(VONAGE_APPLICATION_ID)
        .privateKeyPath(VONAGE_PRIVATE_KEY_PATH)
        .build();

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Write the code

Add the following to the main method of the TransferCall class:

/*
Establish a call for testing purposes.
 */
final String ANSWER_URL = "https://nexmo-community.github.io/ncco-examples/long-tts.json";
CallEvent call = client.getVoiceClient().createCall(new Call(
        TO_NUMBER,
        VONAGE_NUMBER,
        ANSWER_URL
));

/*
Give them time to answer.
 */
Thread.sleep(10000);

final String UUID = call.getUuid();
final String NCCO_URL = "https://nexmo-community.github.io/ncco-examples/talk.json";
client.getVoiceClient().transferCall(UUID, NCCO_URL);

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Run your code

We can use the application plugin for Gradle to simplify the running of our application. Update your build.gradle with the following:

  apply plugin: 'application'
  mainClassName = project.hasProperty('main') ? project.getProperty('main') : ''

Run the following gradle command to execute your application, replacing com.vonage.quickstart.voice with the package containing TransferCall:

gradle run -Pmain=com.vonage.quickstart.voice.TransferCall

Prerequisites

Install-Package Vonage

Create a file named TransferCall.cs and add the following code:

using Vonage;
using Vonage.Request;
using Vonage.Voice;

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Add the following to TransferCall.cs:

var credentials = Credentials.FromAppIdAndPrivateKeyPath(VONAGE_APPLICATION_ID, VONAGE_PRIVATE_KEY_PATH);
var client = new VonageClient(credentials);

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Write the code

Add the following to TransferCall.cs:

var callEditCommand = new CallEditCommand()
{
    Action = CallEditCommand.ActionType.transfer,
    Destination = new Destination()
    {
        Url = new[] { NCCO_URL }
    }
};

var response = client.VoiceClient.UpdateCall(UUID, callEditCommand);

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Prerequisites

composer require vonage/client

Create a file named index.php and add the following code:

$keypair = new \Vonage\Client\Credentials\Keypair(
    file_get_contents(VONAGE_APPLICATION_PRIVATE_KEY_PATH),
    VONAGE_APPLICATION_ID
);

$client = new \Vonage\Client($keypair);

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Write the code

Add the following to index.php:

$call = $client->voice()->get(UUID);
$client->voice()->transferCall(
    $call->getUuid(),
    new \Vonage\Voice\NCCO\Action\Transfer("https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/transfer.json")
);

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Run your code

Save this file to your machine and run it:

php index.php

Prerequisites

pip install vonage

Create a file named transfer-a-call.py and add the following code:

client = vonage.Client(
    application_id=VONAGE_APPLICATION_ID,
    private_key=VONAGE_APPLICATION_PRIVATE_KEY_PATH,
)

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Write the code

Add the following to transfer-a-call.py:

voice = vonage.Voice(client)

dest = {"type": "ncco", "url": ["https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/text-to-speech.json"]}
response = voice.update_call(UUID, action="transfer", destination=dest)
pprint(response)

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Run your code

Save this file to your machine and run it:

python3 transfer-a-call.py

Prerequisites

gem install vonage

Create a file named transfer-a-call.rb and add the following code:


client = Vonage::Client.new(
  application_id: VONAGE_APPLICATION_ID,
  private_key: File.read(VONAGE_APPLICATION_PRIVATE_KEY_PATH)

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Write the code

Add the following to transfer-a-call.rb:


ncco = {"type": "ncco", "url": ["https://raw.githubusercontent.com/nexmo-community/ncco-examples/gh-pages/transfer.json"]}

response = client.voice.transfer(UUID, destination: ncco)

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Run your code

Save this file to your machine and run it:

ruby transfer-a-call.rb

Try it out

You will need to:

Set up a call and obtain the call UUID. You could use the 'connect an inbound call' code snippet to do this.
Run the example code to transfer the call.
Control will be transferred to a new NCCO, and you will hear a text-to-speech message to confirm this.

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