Add files to zip and download zip using php - php

Question

I have a web service that is requesting for data. The data received is being stored in the variable $response.
After that, i am creating files to store the data.
Then i am trying to add these files to a zip and afterwards download that zip. I have consulted various questions and answers similar to mine but i still cannot solve my problem. Note that i have the zip library installed.
Below is my php script:
// Load zip library
$zip = new ZipArchive();
//Zip name
$zip_name = "data.zip";
if($zip->open($zip_name, ZIPARCHIVE::CREATE)!==TRUE){
// Opening zip file to load files
$error = "ZIP creation failed at this time";
}
else{
echo "zip creation successful";
}
function myFunc(){
//Some codes
global $zip;
$myfile = fopen($filepath, "w");
fwrite($myfile, $response);
fclose($myfile);
echo "test1";
try {
//add file to zip
$zip->addFile($myfile);
}
catch (Exception $e) {
echo $e->getMessage();
}
echo "test2";
}
$zip->close();
//Some codes
if(file_exists($zip_name)){
// push to download the zip
header('Content-type: application/zip');
header('Content-Disposition: attachment; filename="'.$zip_name.'"');
readfile($zip_name);
// remove zip file is exists in temp path
unlink($zip_name);
}
After running the above script, test1 is being displayed and not test2. I think that the problem lies in this line $zip->addFile($myfile);.
From previous posts, i could notice that the function addFile takes 2 parameters. How can i edit my code for this?
Thanks for your help.