在php类中打开mysql连接时出现问题

Question

I am trying to create my own class to handle mysql interactions on a test site I'm making. I can't get the mysqli_connect() to work within the class declaration. Every time I try to use the class in a script I get this syntax error:

Parse error: syntax error, unexpected '(', expecting ',' or ';' in C:\\xampp\\htdocs\\autoshop\\classes\\class_db.inc.php on line 7

Here is the code I have so far:

<?php 
class Db{
    private $host = 'localhost';
    private $db_user = 'username';
    private $db_pass = 'password';
    private $db_name = 'dbname';
    private $con = mysqli_connect($this->host, $this->db_user, $this->db_pass, $this->db_name) or die('failed to connect');

    public function valid_login($login_user, $login_pass){

        if(isset($login_user) && isset($login_pass) && ($login_user !== "") && ($login_pass !== "")){
            include('./includes/functions.php');

            $clean_lu = mysqli_real_escape_string($this->con, $login_user);
            $clean_lp = mysqli_real_escape_string($this->con, $login_pass);

            $login_query = "SELECT hash FROM users WHERE user_name='$clean_lu'";
            $login_results = mysqli_query($this->con, $login_query) or die('bad query');
            $login_hash = mysqli_fetch_array($login_results);

            if(isset($login_hash[0])){
                if(check_hash($clean_lp, $login_hash[0])){
                    return true;
                }else{
                    return false;
                }
            }else{
                return false;
            }
        }
    }

    mysqli_close($this->con);   
}
?>

I keep looking at that line and I can't find any bad syntax.

I apologize if this is a really simple solution that's right in front of my face, I'm pretty new at this whole developer thing.

Answer 1

You cannot initialize object's member with result of function call. Perform this in your constructor instead.

class Db
{
    private $con;

    public function __construct()
    {
        $this->con = mysqli_connect($this->host, $this->db_user, $this->db_pass, $this->db_name) or die('failed to connect');
    }
    ...
}

Also, where is mysqli_close($this->con); located? It doesn't belong to any of methods.

Btw, any reason to close connection manually at all?

Answer 2

maybe try this

$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'my_db');
if ($mysqli->connect_error) 
{
trigger_error('Connect Error (' . $mysqli->connect_errno . ') '
        . $mysqli->connect_error);
}