gistfile1.txt

/////////////////////////////////////////////////////////////////////////////////////////////////////////
// HTML

<form action="" method="post" id="enter_number">
  <p>Enter your phone number:</p>
  <p><input type="text" name="phone_number" id="phone_number" /></p>
  <p><input type="submit" name="submit" value="Verify" /></p>
</form>

<div id="verify_code" style="display:none;">
  <p>Calling you now.</p>
  <p>When prompted, enter the verification code:</p>
  <h1 id="verification_code"></h1>
  <p><strong id="status">Waiting...</strong></p>
</div>





/////////////////////////////////////////////////////////////////////////////////////////////////////////
// Javascript

$(function(){

	var initiateCall = function() {
		$.post(
			'call.php',
			{phone_number:( $('#phone_number').val() || false )},
			function( data ) {
				showCodeForm( data.verification_code);
			},
			'json'
		);
		checkStatus();
	},
	showCodeForm = function( code ) {
		$("#verification_code").text(code);
		$("#verify_code").fadeIn();
		$("#enter_number").fadeOut();
	},
	checkStatus = function() {
		$.post( 
			'status.php',
			{phone_number:( $('#phone_number').val() || false )},
			function( data ) {
				updateStatus( data.status );
			},
			'json'
		);
	},
	updateStatus = function( current ) {
		if( current === 'unverified' ) {
			$('#status').append( '.' );
			setTimeout( checkStatus, 2000 );
		}
		else {
			$('#status').text( 'Verified!' );
		}
	};

	$('#enter_number').submit( function( e ) {
		e.preventDefault();
		initiateCall();
	});

});





/////////////////////////////////////////////////////////////////////////////////////////////////////////
// call.php

<?php

require_once( 'Services/Twilio.php' );
require_once( 'database.php' );

header( 'Content-type: application/json' );

// require POST request
if( $_SERVER['REQUEST_METHOD'] != 'POST' ) {
	echo json_encode( array( 'error' => 'Data not valid.' ) ):
	exit;
}

// generate "random" 6-digit verification code
mt_seed( sprintf( '%u', crc32( $_SERVER['REMOTE_ADDR'] ) ).time() );
$code = mt_rand( 100000, 999999 );

// save verification code in DB with phone number
// does not check for duplicates like it should
$number = sprintf( '%u', preg_replace( '/[^0-9]/', '', $_POST['phone_number'] ) );

// check if resulting number is actually a number (yeah we quickly cast a str on it)
if( !is_numeric( $number ) && strlen( $number ) == 10 ) {
	echo json_encode( array( 'error' => 'Phone number not valid.' ) ):
	exit;
}

// phone_number is unique and an unsigned INT
db( sprintf( 'INSERT INTO numbers SET phone_number = %u, verification_code = %d ON DUPLICATE verification_code = %2$d', $number, $code ) );

// initiate phone call via Twilio REST API    
// Set our AccountSid and AuthToken 
$twilio = array();
$twilio['id'] 		= 'ACxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
$twilio['token']	= 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';

// Instantiate a new Twilio Rest Client 
$client = new Services_Twilio( $twilio['id'], $twilio['token'] );

try {
	// make call
	$call = $client->account->calls->create(
				'+18881234567',                // Verified Outgoing Caller ID or Twilio number
				$number,                       // The phone number you wish to dial
				'http://example.com/twiml.php' // The URL of twiml.php on your server
	);
} catch( Exception $e ) {
	echo json_encode( array( 'error' => 'Error starting phone call: '.$e->getMessage() ) );
	exit;
}

// return verification code as JSON

echo json_encode( array( 'error' => false, verification_code' => $code ) );
exit;

?>





/////////////////////////////////////////////////////////////////////////////////////////////////////////
// twiml.php

<?php

require_once( 'Services/Twilio.php' );
require_once( 'database.php' );

$response = new Services_Twilio_Twiml();

if( empty( $_POST['Digits'] ) ) {
	$gather = $response->gather( array( 'numDigits' => 6 ) );
	$gather->say( 'Please enter your verification code.' );
}
else {
	// grab db record and check for match
	$called = sprintf( '%u', preg_replace( '/[^0-9]+/', '', $_POST['Called'] ) );
	$result = db( sprintf( 'SELECT verification_code FROM numbers WHERE phone_number = %u', $called ) );
	if( $line = mysql_fetch_assoc( $result ) ) {
		if( $_POST['Digits'] === $line['verification_code'] ) {
			db( sprintf( 'UPDATE numbers SET verified = 1 WHERE phone_number = %u', $called );
			$response->say( 'Thank you! Your phone number has been verified.' );
		}
		else {
			// if incorrect, prompt again
			$gather = $response->gather( array( 'numDigits' => 6 ) );
			$gather->say( 'Verification code incorrect, please try again.' );
		}
	}
}

echo $response;
exit;

?>