显示某些级别PHP的内容

Question

I'm creating a simple staff panel that consists of just about 10 pages and uses a single sql table. My sql table consists of user_id, user_name, user_email, password and rank

I'm trying to display specific content based on what the users rank is in the database although, I'm a very beginner at PHP so I'm not even sure if I'm pulling it from the database properly.

                $sql = "SELECT user_name, user_email, user_password_hash, user_id, rank
                    FROM users
                    WHERE user_name = '" . $user_name . "' OR user_email = '" . $user_name . "';";
            $result_of_login_check = $this->db_connection->query($sql);

            // if this user exists
            if ($result_of_login_check->num_rows == 1) {

                // get result row (as an object)
                $result_row = $result_of_login_check->fetch_object();

                // using PHP 5.5's password_verify() function to check if the provided password fits
                // the hash of that user's password
                if (password_verify($_POST['user_password'], $result_row->user_password_hash)) {

                    // write user data into PHP SESSION (a file on your server)
                    $_SESSION['user_name'] = $result_row->user_name;
                    $_SESSION['rank'] = $result_row->rank;
                    $_SESSION['user_email'] = $result_row->user_email;
                    $_SESSION['user_login_status'] = 1;

This is my login.php file.
This is the code I'm using to try and display something to a specific rank.

I've managed to do it so it will display something depending on the users name which leads me to believe I haven't called rank properly.

<?php
if (isset($_SESSION['rank']) && $_SESSION['rank'] == admin) {
echo '<a href="/admin/" class="btn btn-danger">Admin</a>';
} else {
echo " ";
}
?>

Answer 1

If the code you have posted is the exact same code you have on your files, then I believe the following line of code is your problem:

if (isset($_SESSION['rank']) && $_SESSION['rank'] == admin) {

Unless admin as been defined through the define function then I take it it is a string, therefore your code should be:

if (isset($_SESSION['rank']) && $_SESSION['rank'] == 'admin') {

Or:

if (isset($_SESSION['rank']) && $_SESSION['rank'] == "admin") {

Either single or double quotes would be fine. I don't see any other reason for the code to fail.

I hope this helps.

Follow up:

You can use the next piece of code to use different ranks as per your comment:

if (isset($_SESSION['rank'])) {
  if ($_SESSION['rank'] == 'admin') {
    // do admin
  } elseif ($_SESSION['rank'] == 'mod') {
    // do mod
  } elseif ($_SESSION['rank'] == 'member') {
    // do member
  }
}

You can also use the switch / case clause:

if (isset($_SESSION['rank'])) {
  switch ($_SESSION['rank']) {
    case: 'admin':
      // do admin
      break; // do not forget the breaks!

    case: 'mod':
      // do mod
      break;

    case: 'member':
      // do member
      break;
  }
}

Hope this helps you even more.