显示使用php，pdo和mysql的当前登录用户的简单计数器

Question

I have been searching for days for such a very simple counter that displays a number of currently logged in users on my website - however, have had no luck finding anything. And the stuff I have found all relates to the deprecated *mysql_functions.... :( - sigh...

All I am looking for is how to make this work as I literally cannot figure this out - one would think it is very easy but holy crap, after searching and searching, it seems like there are just so many different ways to accomplish this and sadly everything I have found is what I mentioned above (stuff using the deprecated mysql_functions)...

Anyway, this is all that I am looking to do:

1.) Adding lastactivity or lastseen in my users table either based on a timestamp or perhaps a tinyint(1) with default 0 which equals user logged out of which would switch to 1 if user is logged in...

2.) Creating a class for this using php version (5.4.24) with PDO driver based on what is in my database table users which would update and select what is in my database table users every 5-10 minutes which would output the number of currently logged in users.

3.) Being able to use <?php echo $lastactivity; ?> <?php echo $lastactivity; ?> or <?php echo $lastseen; ?> <?php echo $lastseen; ?> to display the number of users currently logged in on each page I place this piece of code on...

4.) All of which trying to stay away from basing this on SESSIONS if possible...

If anyone could shed some light on how to accomplish this, I would be very grateful!

UPDATE:

what would be in my users table:

lastseen | tinyint(1) | Default 0
lastactivity | timestamp | Default CURRENT_TIMESTAMP

what I currently have in my users.php class page - I'll display everything I have atm so be prepared for a lot - nothing pertaining to a counter of logged in users is in this yet, however, with what I do have I hope will shed some light on how to add what I need to it...:

class Users {

    private $db;

    public function __construct($database) {
        $this->db = $database;
    }

    public function update_user($clan_tag,
                    $gamer_tag,
                    $gender,
                    $day,
                    $month,
                    $year,
                    $location,
                    $occupation,
                    $interests,
                    $bio,
                    $status,
                    $xfire,
                    $steam,
                    $image_location,
                    $id) {

        $query = $this->db->prepare("UPDATE `users` SET
                                `clan_tag`      = ?,
                                `gamer_tag`     = ?,
                                `gender`        = ?,
                                `day`           = ?,
                                `month`         = ?,
                                `year`          = ?,
                                `location`      = ?,
                                `occupation`        = ?,
                                `interests`     = ?,
                                `bio`           = ?,
                                `status`        = ?,
                                `xfire`         = ?,
                                `steam`         = ?,
                                `image_location`    = ?

                                WHERE `id`      = ?");

        $query->bindValue(1, $clan_tag);
        $query->bindValue(2, $gamer_tag);
        $query->bindValue(3, $gender);
        $query->bindValue(4, $day);
        $query->bindValue(5, $month);
        $query->bindValue(6, $year);
        $query->bindValue(7, $location);
        $query->bindValue(8, $occupation);
        $query->bindValue(9, $interests);
        $query->bindValue(10, $bio);
        $query->bindValue(11, $status);
        $query->bindValue(12, $xfire);
        $query->bindValue(13, $steam);
        $query->bindValue(14, $image_location);
        $query->bindValue(15, $id);

        try{
            $query->execute();
        }catch(PDOException $e){
            die($e->getMessage());
        }
    }
    // update_status below has been duplicated from what is above to suit needs. Without this update, status update does not work in logster.php!
    public function update_status($status, $id){

        $query = $this->db->prepare("UPDATE `users` SET
                                `status`        = ?
                                WHERE `id`      = ?");

        $query->bindValue(1, $status);
        $query->bindValue(2, $id);

        try{
            $query->execute();
        }catch(PDOException $e){
            die($e->getMessage());
        }
    }

    public function change_password($user_id, $password) {

        global $bcrypt;

        $password_hash = $bcrypt->genHash($password);

        $query = $this->db->prepare("UPDATE `users` SET `password` = ? WHERE `id` = ?");

        $query->bindValue(1, $password_hash);
        $query->bindValue(2, $user_id);

        try{
            $query->execute();
            return true;
        } catch(PDOException $e){
            die($e->getMessage());
        }
    }


        public function fetch_info($what, $field, $value){
        /* (Add more here if new columns/rows are added to table) */
        $allowed = array('id',
                 'username',
                 'clan_tag',
                 'gamer_tag',
                 'gender',
                 'day',
                 'month',
                 'year',
                 'location',
                 'occupation',
                 'interests',
                 'bio',
                 'status',
                 'xfire',
                 'steam',
                 'email');

        if (!in_array($what, $allowed, true) || !in_array($field, $allowed, true)) {
            throw new InvalidArgumentException;
        }else{

            $query = $this->db->prepare("SELECT $what FROM `users` WHERE $field = ?");

            $query->bindValue(1, $value);

            try{

                $query->execute();

            } catch(PDOException $e){

                die($e->getMessage());
            }

            return $query->fetchColumn();
        }
    }


    public function user_exists($username) {

        $query = $this->db->prepare("SELECT COUNT(`id`) FROM `users` WHERE `username`= ?");
        $query->bindValue(1, $username);

        try{

            $query->execute();
            $rows = $query->fetchColumn();

            if($rows == 1){
                return true;
            }else{
                return false;
            }

        } catch (PDOException $e){
            die($e->getMessage());
        }
    }

    public function login($username, $password) {

        global $bcrypt;

        $query = $this->db->prepare("SELECT `password`, `id` FROM `users` WHERE `username` = ?");
        $query->bindValue(1, $username);

        try{

            $query->execute();
            $data               = $query->fetch();
            $stored_password        = $data['password'];
            $id                 = $data['id'];

            if($bcrypt->verify($password, $stored_password) === true){
                return $id;
            }else{
                return false;
            }

        }catch(PDOException $e){
            die($e->getMessage());
        }
    }

    public function userdata($id) {

        $query = $this->db->prepare("SELECT * FROM `users` WHERE `id`= ?");
        $query->bindValue(1, $id);

        try{

            $query->execute();

            return $query->fetch();

        } catch(PDOException $e){

            die($e->getMessage());
        }
    }

    public function get_users() {

        $query = $this->db->prepare("SELECT * FROM `users` ORDER BY `time` DESC");

        try{
            $query->execute();
        }catch(PDOException $e){
            die($e->getMessage());
        }

        return $query->fetchAll();
    }
}

What would be included on each page to display number of currently logged in users:

either <?php echo $lastseen; ?> <?php echo $lastseen; ?> or <?php echo $lastactivity; ?> <?php echo $lastactivity; ?>

UPDATE 2:

Including my logout function:

class General{
        // Note: Created to specify what logged in users can see/view and edit/update
    public function logged_in () {
        return(isset($_SESSION['id'])) ? true : false;
    }
        // Note: Created to specify what a specific individual or user can see/view and edit/update
    public function logged_in_protect() {
        if ($this->logged_in() === true) {
                header('Location: home.php');
            exit();
        }
    }
        // Note: Created to specify what non-users - (those who are not logged in and/or do not have an account) can see/view only - (edit/update is unavailable)
    public function logged_out_protect() {
        if ($this->logged_in() === false) {
            header('Location: index.php');
            exit();
        }
    }
}

UPDATE 3:

session_start();
session_destroy();
header('Location:index.php');

Answer 1

1. Instead of "lastseen", let's call the column "loggedIn". That way, a boolean 0 or 1 makes sense. Expand your existing login function to change loggedIn from 0 to 1:

    if($bcrypt->verify($password, $stored_password) === true){ return $id; //update database $query = $this->db->prepare("UPDATE `users` SET `loggedIn` = `1` WHERE `username` = ?"); $query->bindValue(1, $username); $query->execute(); }else{ return false; } 

Obviously you'll need a similar statement in the logout function to set the value back to 0.

2 & 3. You could then add this as an additional function of the Users class:

public function usersLoggedIn() {
    $query = $this->db->prepare("SELECT COUNT(*) AS loggedInCount FROM users 
                                 WHERE loggedIn = 1");
    try {
        $query->execute();

        while ($row = $query->fetch()) {   
            $loggedIn = $row['loggedInCount'];
        }
        return $loggedIn;

    } catch(PDOException $e) {
        die($e->getMessage());
    }
}