Add more variables in the URL via GET - php

Question

I want to do have the possibility to pass parameters through the URL example.
www.example.com/index.php?msg=textOne&var2=textTwo&var3=textThree.
what do I need to change the code to make it work?
<?php
define("GOOGLE_API_KEY", ...);
define("GOOGLE_GCM_URL", "https://android.googleapis.com/gcm/send");
function send_gcm_notify($reg_id, $message, $text) {
$fields = array(
'registration_ids' => array( $reg_id ),
'data' => array( "message" => $message ),
);
$headers = array(
'Authorization: key=' . GOOGLE_API_KEY,
'Content-Type: application/json'
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, GOOGLE_GCM_URL);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));
$result = curl_exec($ch);
if ($result === FALSE) {
die('Problem occurred: ' . curl_error($ch));
}
curl_close($ch);
echo $result;
}
$reg_id = "APA91bHuSGES.....nn5pWrrSz0dV63pg";
$msg = filter_input (INPUT_GET, 'msg', FILTER_SANITIZE_STRING);
send_gcm_notify($reg_id, $msg,put);

Answer 1

If you want to use the array style:
....
$getParams = array(
'param1' => 'value',
'param2' => 'value2',
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, GOOGLE_GCM_URL . '?' . implode('&', array_map('urlencode', $getParams)));
curl_setopt($ch, CURLOPT_POST, true);
....
Notice the usage of urlencode to insure your parameters are URL safe.