Foreach loop, and array building - php

Question

I have an admin area where they can delete multiple users at a time. This is part of the code that handles the deletion. Basically it goes through the user ids and deletes each one that was marked checked.
if ($_POST['doDelete'] == 'Delete') {
if (!empty($_POST['u'])) {
foreach ($_POST['u'] as $uid) {
$id = escape($uid);
$delete = Nemesis::query("DELETE FROM users WHERE id = '{$id}' AND id <> '{$_SESSION[user_id]}'");
if (!$delete) {
$msg->add('e', QUERY_ERROR);
redirect('users.php');
exit();
}
}
}
/* we need a way to iterate over users deleted */
$msg = new Messages();
$msg->add('s', QUERY_DELETE_SUCCESS);
redirect('users.php');
exit();
}
function get_user_name_from_id($user_id)
{
if ($_SESSION['user_level'] == ADMIN_LEVEL) {
$viewUserMod = 1;
} else {
$config = Nemesis::select("usr_view_cm", "config");
$row_config = $config->fetch_assoc();
$viewUserMod = $row_config['usr_view_cm'];
}
if (is_numeric($user_id) && $viewUserMod == 1) {
$sql = Nemesis::select("full_name", "users", "id = {$user_id}");
if ($sql->num_rows > 0) {
$user_name = $sql->fetch_assoc();
return $user_name['full_name'];
} else {
// user name cannot be matched with db, either error, or most likely user was deleted
return 'User ' . $user_id;
}
} else {
return $user_id;
}
}
Where it says QUERY_DELETE_SUCCESS I would like to output something like "Deleted Bob, Jack, Tim" .etc I have a function that uses the users id and gets their names. The issue is that once the iteration is complete. Obviously those users no longer exist in the database and I cannot get their names. Is there a way of running this function during the loop, and building a string or array. That can be outputted in place of the message?

Answer 1

You should just be able to do this:
if ($_POST['doDelete'] == 'Delete') {
$deleted = array();
if (!empty($_POST['u'])) {
foreach ($_POST['u'] as $uid) {
$id = escape($uid);
$username = get_user_name_from_id($uid);
$delete = Nemesis::query("DELETE FROM users WHERE id = '{$id}' AND id <> '{$_SESSION[user_id]}'");
if (!$delete) {
$msg->add('e', QUERY_ERROR);
redirect('users.php');
exit();
}
$deleted[] = $username // push name to array after deletion is successful
}
}
/* The $deleted array now holds the names of the deleted users.
* Do with it what you want.
*/
$names = implode(",", $deleted)
$msg = new Messages();
$msg->add('s', QUERY_DELETE_SUCCESS . " Deleted: $names");
redirect('users.php');
exit();
}
There are several improvements that can be made here, including efficiency (combining many small single queries into a few larger ones) and error handling (don't redirect on the first error - instead redirect after all processing is complete to a page with a list of successes and errors), but this is the basic idea.
Here is a quick change that will do all of the operations, even if one of them errors:
if ($_POST['doDelete'] == 'Delete') {
$deleted = array();
$errored = array();
if (!empty($_POST['u'])) {
foreach ($_POST['u'] as $uid) {
$id = escape($uid);
$username = get_user_name_from_id($uid);
$delete = Nemesis::query("DELETE FROM users WHERE id = '{$id}' AND id <> '{$_SESSION[user_id]}'");
if (!$delete) {
$errored[] = $username;
} else {
$deleted[] = $username // push name to array after deletion is successful
}
}
}
/* The $deleted array now holds the names of the deleted users.
* The $errored array now holds the names of users who were not deleted due to errors.
* Do with them what you want.
*/
$msg = new Messages();
$names_deleted = implode(",", $deleted)
$msg->add('s', QUERY_DELETE_SUCCESS . " Deleted: $names_deleted");
if (count($errored) > 0) {
$names_errored = implode(",", $errored)
$msg->add('e', QUERY_ERROR . " Did not delete: $names_errored");
}
redirect('users.php');
exit();
}

Answer 2

You could add the names to an array as you are looping over the uids with something like this:
$names = array();
if (!empty($_POST['u'])) {
foreach ($_POST['u'] as $uid) {
$names[] = get_user_name_from_id($uid);
$id = escape($uid);
$delete = Nemesis::query("DELETE FROM users WHERE id = '{$id}' AND id <> '{$_SESSION[user_id]}'");
if (!$delete) {
$msg->add('e', QUERY_ERROR);
redirect('users.php');
exit();
}
}
}
Then when you want to output the confirmation message, you could turn that array into a comma separated string with something like this:
$names = implode(', ',$names);
$message = "Deleted $names";