How to use system command in php? - php

Question

I am working on a PHP code as shown below in which conversion of mp4 into mp3 is happening at Line B.
I have added if block after system command to print Conversion Completed on the webpage once the conversion is complete but it doesn't seem to work.
Php code:
if (isset($_POST['id']))
{
for($i=0; $i <count($mp4_files); $i++) {
if($i == $_POST['id']) {
$f = $mp4_files[$i];
$parts = pathinfo($f);
switch ($parts['extension'])
{
case 'mp4' :
$filePath = $src_dir . DS . $f;
print_r($f); // Line A
system('ffmpeg -i ' . $filePath . ' -map 0:2 -ac 1 ' . $destination_dir . DS . $parts['filename'] . '.mp3', $result); // Line B
if($result)
{
echo "Conversion Completed";
}
}
}
}
}
Problem Statement:
I am wondering what changes I should make in the PHP code above so that once the conversion is complete; on the webpage, it should print Conversion Completed.

Answer 1

You can use shell_exec to get a return value and then put that in an if statement like this
$output = shell_exec('ffmpeg -i ' . $filePath . ' -map 0:2 -ac 1 ' . $destination_dir . DS . $parts['filename'] . '.mp3');
if ($output) {
echo "Conversion Completed!";
// or redirect here
}
Also, make sure to sanitize your inputs as they are exposed to a CLI interface.