PHP Checkbox delete files from folder - php

Question

I want to delete files from folder called "fajlovi". Multiple and singled delete should work. But it delete first file in folder (0 position in array of files in the folder). If I check any for files it will delete first 4 files instead files I checked. Here is the code:
$a = glob("fajlovi/*");
echo "<br>var_dump of \$a ------------------------<br><pre>";
var_export($a);
echo "</pre>end dump od \$a ------------------------<br><br>";
echo "Number od files in the directory: " . count($a) . "<br>";
echo "<form method='POST' action='" . $_SERVER['PHP_SELF'] . "'><table >";
echo "<th>File name:</th><th>Size MB:</th><th>Delete:</th>";
foreach ($a as $key => $value) {
echo "<tr><td>" . $value . "</td>";
echo "<td>" . round(filesize($value) / 1024 / 1024, 5) . " MB <br></td>";
echo "<td><input type='checkbox' name='checked[]'>" . $img_number = $key + 1 . "</td>";
}
echo "<tr><td colspan=3><input type='submit' name='delete' value='Delete'></td></tr>";
echo "</table></form>";
if (isset($_POST['delete'])) {
$checkbox = $_POST['checked'];
for ($i = 0; $i <= count($a); $i++) {
if (isset($checkbox[$i])) {
if (unlink($a[$i])) {
echo "Successfully deleted file" . $a[$i] . "<br>";
}
}
}
}
if (!empty($_POST['checked'])) {
var_dump($_POST['checked']);
}
1. This is screenshot of the page:
2.then I check images I want to delete:
3. After pressing Delete button, this is the result:
4. And after entering the page again, we can see that wrong images are deleted:

Answer 1

You need to give your inputs a value
<input type='checkbox' name='checked[]' value='{$key}'>
Here's some code to bump you in the right direction.
$files = glob('fajlovi/*');
$indicesToDelete = array_intersect((array)($_POST['checked'] ?? []), array_keys($files));
foreach ($indicesToDelete as $index) {
if (unlink($files[$index])) {
echo "Successfully deleted file" . $files[$index] . "<br>";
}
}
I wouldn't be implementing the deletion like this though. Instead of using the indexes provided by glob() as your method of locating files to delete, you should be using a key that uniquely and definitively identifies the file. At the very least this means using the filepath itself. Consider for example a scenario in which file(s) are added ore removed between when your form displays and you make and submit your selections for deletion. You could end up removing the wrong files.
Instead you might pass the filepath here:
<input type='checkbox' name='checked[]' value='{$value}'>
And then work with them instead of indices.
$files = glob('fajlovi/*');
$pathsToDelete = array_intersect((array)($_POST['checked'] ?? []), $files);
foreach ($pathsToDelete as $filepath) {
if (unlink($filepath)) {
echo "Successfully deleted file" . $files[$index] . "<br>";
}
}
As a final bit of advice:
You should check file_exists(), is_file(), or similar before doing the unlink. You should be doing everything you can to ensure you're only allowing the deletion of the files you intended.