CallMeButton

Overview

CallMeButton is an App written in PHP that enables users to place calls. It uses the PhoneCall resource exposed by Unified API and the following requests:

• Create PhoneCall - Creates phone calls using any given source and destination
• List PhoneCall - Fetches the list of in progress phone calls in the system at a point of time

Installation

In order to be able to use the CallMeButton App, you need a web server with PHP 5.3 or higher installed.

STEP 1: Switch to the directory that can be accessed over web (e.g /var/www/html) and clone the Git repository:

You also need to give proper permissions and ownership rights to the files of the App. The App needs to be owned by the web server user and group.

For example, if httpd is the name of the user and the name of the group to which the webserver belongs to:

chmod -R 755 <PATH_TO_CallMeButton>

chown -R httpd:httpd <PATH_TO_CallMeButton>

In order to use the App, you must configure it by opening the file <PATH_TO_CallMeButton>/config/config.php and changing the following settings:

Behavior

User Interface

As soon as the setup process is complete, the user may access the interface at https://<hostname>//PATH_TO_callmebutton/index.php. The following form is displayed where the user can enter his/hers phone number:

After the user enters the number and clicks the Call Me button, the App displays to the user the details of the call.

Internal Flow

Place a Phone Call

To place the phone call, the App uses the Unified API Create Simple PhoneCalls request. It uses the extension defined in the global variable VN_EXTENSION as the source of the call as in the example below. All fields are fictitious.

POST /uapi/phoneCalls/@me/simple HTTP/1.1
HOST x.x.x.x
Content Type: application/json
Authorization: <OAUTH_ACCESS_TOKEN>
 
{
  "extension":"<VN_EXTENSION>",
  "phoneCallView":[
    {
       "source":["<VN_EXTENSION>"],
       "destination":["8887777"]
       "callerId":"CallMeButton <8887777>"
    }
  ]
}

The code that makes the request can be found in <Path_To_CallMeButton>/plib/lib.php and is described below:

// Fetch token
$token = getToken();
$headers = array(
   'Content-type' => 'application/json',
   'Authorization' => $token
);
 
// Initialize the cURL request
$reqUrl = 'https://'.$config['VN_SERVER_IP'].'/uapi/phoneCalls/@me/simple';
$request = new cURLRequest();
$request->setMethod(cURLRequest::METHOD_POST);
$request->setHeaders($headers); 
    
$jsonRequest = array(
	'extension' => $config['VN_EXTENSION'],				    // Number of the extension configured to run with CallMeButton
	'phoneCallView' => array(
		array('source' => array($config['VN_EXTENSION']),	// Number of the extension configured to run with CallMeButton
	          'destination' => $phoneNumber                 // The phone number entered in the form field.
     )
);
$request->setBody(json_encode($jsonRequest));

// Receive the response in JSON format
$response = $request->sendRequest($reqUrl);									     

The source and extension request parameters can be different as described in the Create Simple PhoneCalls recommendations. The CallMeButton App uses the same extension for both parameters.

Behavior

STEP 1: The system first calls the VN_EXTENSION

STEP 2: The system calls next the number entered by the user in the form

STEP 3: The system connects the two parties and returns the response using the JSON format. The response contains the phone call ID which is later used to fetch the call details as demonstrated below.

List the Phone Call

CallMeButton queries the server every 5 seconds to verify the status of the call and displays it to the user. This is accomplished by making the following Unified API request.

GET /uapi/phoneCalls/@me/<VN_EXTENSION>/<phoneCallID>
HOST x.x.x.x
Content Type: application/json
Authorization: <OAUTH_ACCESS_TOKEN>