PHPMailer sanitizing multiple attachments - php

Question

I am trying to limit the file size and type of attachments processed by phpmailer. The answer in this post does not solve the multiple attachments issue. The issue seems to be the form's input name with [] which converts form input to array. I am not able to write its correct syntax.
HTML is:
<input type="file" multiple="multiple" name="attach_file[]" />
PHP is:
<?php
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;
require 'src/Exception.php';
require 'src/PHPMailer.php';
$name = $_POST['name'];
$mail = new PHPMailer(true);
try {
$mail->setFrom('abc#abc.org', 'abc');
$mail->addAddress('xyz#xyz.com', 'xyz');
// Attachments
foreach(array_keys($_FILES['attach_file']['name']) as $key) {
$source = $_FILES['attach_file']['tmp_name'][$key];
$filename = $_FILES['attach_file']['name'][$key];
$mail->AddAttachment($source, $filename);
}
$mail->isHTML(true);
$mail->Subject = 'Case History';
$mail->Body = $name;
$mail->send();
echo 'Message has been sent';
}
catch (Exception $e) {
echo "Message could not be sent. Mailer Error: {$mail->ErrorInfo}";
}
If in foreach loop I use this:
$maxsize = 2 * 1024 * 1024; // 2 MB
$types = array('image/png', 'image/jpeg', 'image/gif'); // allowed mime-types
if(filesize($filename) < $maxsize && in_array(mime_content_type($filename),$types)){
$mail->AddAttachment($source, $filename);
}
I get these errors :
filesize(): stat failed
mime_content_type(): failed to open stream.
No such file or directory
What is the correct way of writing the IF condition when input name is for multiple attachments. Thanks.

Answer 1

You should note that $filename is just the original name of the file that has been uploaded (e.g. photo.jpg) - but the filesystem pathname of the uploaded file is actually $source (always some random filename, sitting in the OS temp folder).