AutoDownload a file with PHP - php

Question

I'm doing a little script that convert a csv to json with php.
I would like that, when you upload the file and the conversion is done, the converted file is automatically downloaded
exec(/*some stuff*/); // i call the script that convert the csv into json, i get my converted file path back
chmod($newFilePath, 0777); // i give all access to the new file
startDownload($newFilePath); // i ask the autoDownload
And here is the download function
function startDownload($path){
if (file_exists($path)) {
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.basename($path));
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($path));
readfile($path);
exit();
}
}
If I echo readfile($path); or filesize($path) I got the file content (which is exactly want i want) and the good informations, and I'm sure the path is correct. But when i execute the script nothing happens.
I'm probably missing something dumb ^^
How can I make the user download this json file?
I tried to make a link and he do the same, is this a problem of access or something like that?
EDIT :
I tester this script in Local, it works perfectly, so the problem is from the permissions or something like that. I'm really bad with this kind of stuff, so if you have some idea that could help ^^
Thx for the help!

Answer 1

Missing semicolon after exec :
exec(); // i call the script that convert the csv into json, i get my converted file path back
chmod($newFilePath, 0777); // i give all access to the new file
startDownload($newFilePath); // i ask the autoDownload
I woul'd check if chmod has really changed the path permission:
if(chmod($newFilePath, 0777)){
startDownload($newFilePath);
}else{
die('Permission denied');
}