Forward a Call Via Voice Proxy with PHP

This sample shows you how to proxy a voice call so that it appears to come from another number. It accompanies this blog post.

Dependencies

The slim micro framework for web applications. Install it using composer:

composer require slim/slim:^3.8

Buy a number

You can do this from either the developer dashboard or by using the [Nexmo CLI](Nexmo CLI):

npm install -g nexmo-cli 

Then, configure Nexmo CLI using your API key and secret (also in the developer dashboard:

nexmo setup YOUR_API_KEY YOUR_API_SECRET

Search for a voice-enabled number, providing a two digit country code, e.g. 'US' or 'GB':

nexmo number:search COUNTRY_CODE --voice

Buy the numnber:

nexmo number:buy NUMBER

Create a Voice API application and link your number to it

Specify the URLs for the publicly-accessible webhooks in index.php.

nexmo app:create “My Voice Proxy” ANSWER_URL EVENT_URL --keyfile private.key

Use the application_id returned by the above to link your number:

nexmo link:app NEXMO_NUMBER APPLICATION_ID

Configure the application

Edit php.ini with the location and name of the file where you want to log call events.

Edit the FROM_NUMBER and TO_NUMBER constants in index.php with your own values. The first should be the Nexmo virtual number you purchased above, the second should be another number that you own that will receive the call.

Run the application

Launch the application, e.g. (using the PHP built-in web server):

php -S localhost:3000 -c php.ini

Call the number you configured in TO_NUMBER. The device should ring but the call will appear to have been made from your Nexmo virtual number rather than the on you used to place the call.