PHP MySQLi database wrapper

Question

I am developing a mysqli database wrapper. I've made an effort to make this as fast as possible and easy to use.

However, now I want to start adding callbacks (for fetch), and make this mysqli-only dependent (still using get_result).

trait dbExtras // connection-independent tools
{
    public function echoQuery()
    {
        $args = func_get_args();
        if (count($args) == 1){
            echo (string) $args[0];
        } else {
            $query = $args[0];
            for($i=1; $i < count($args); $i++){
                $query = preg_replace('/[?]/', "'" . $args[$i] . "'" , $query, 1);
            }
            echo $query;
        }
    }
    public function toJSON($stmt)
    {
        $json = array();
        if ($stmt->num_rows > 0) {
            while($row = $stmt->fetch_array(MYSQL_ASSOC)) {$json[] = $row;}
        }
        return json_encode($json);
    }

    //fetch an array from executed SQL query. mode can also be numeric (MYSQLI_NUM) or both (MYSQLI_BOTH)
    public function fetch($stmt, $mode = MYSQLI_ASSOC)
    {
        return $stmt->fetch_array($mode);
    }


    public function fetchAll($stmt, $mode = MYSQLI_ASSOC) {
         return $stmt->fetch_all($mode);
    }
}

class database
{
    //database vars
    public $connection = null;

    use dbExtras; // include methods

    //  Methods Declaration
    public function __construct($host, $database, $username, $password)
    {
        $db = mysqli_connect($host,$username,$password,$database);
        //Check connection
        if($db->connect_errno > 0) {return false;}
        $this->connection = $db;
        // changed from utf8 to utf8mb4, reason: full int8n support
        $this->connection->set_charset("utf8mb4");
    }

    public function close()
    {
        if ($this->connection != null) {return $this->connection->close();}
    }

    function __destruct()
    {
        $this->close();
    }

    public function runQuery()
    {
        $this->ping();          // reconnects if connection is closed

        $args = func_get_args();
        $cnt = count($args);
        if ($cnt === 1){
            return $this->query($args[0]);
        } else {
            $types = '';
            $bind = mysqli_prepare($this->connection, $args[0]);
            for($i=1; $i < $cnt; $i++){
                switch (gettype($args[$i])) {
                    case 'NULL':
                    case 'string':
                        $types .= 's';
                        break;
                    case 'boolean':
                    case 'integer':
                        $types .= 'i';
                        break;
                    case 'blob':
                        $types .= 'b';
                        break;
                    case 'double':
                        $types .= 'd';
                        break;
                    default:
                        $types .= 's';
                        break;
                }
                $values[] = &$args[$i];
            }
            $params = array_merge(array($types), $values);
            unset($types);
            unset($values);
            // new method, saves 30 - 40 % of exec time. old was call_user_func_array(array($bind, "bind_param"), $params);
            $ref    = new ReflectionClass('mysqli_stmt'); 
            $method = $ref->getMethod("bind_param");
            $method->invokeArgs($bind,$params); 
            unset($params);
            if ($bind->execute()) {
                return $bind->get_result();
            } else {
                return false;
            }
        }
    }

    public function getLastInserted()
    {
        return $this->connection->insert_id;
    }

    public function setAutoCommit($bool = TRUE) // required before complex queries --use with addQuery() & commit()
    {
        $this->connection->autocommit($bool);
    } 

    public function query($sql)
    {
        return $this->connection->query($sql);
    }

    public function commit()
    {
        return $this->connection->commit();
    }

    public function escape($string) 
    {
        return $this->connection->real_escape_string($string);
    }

    public function getAffectedRows()
    {
        return mysqli_affected_rows($this->connection);
    }

    public function ping()
    {
        return mysqli_ping($this->connection);
    }

    public function getError()
    {
        return mysqli_error($this->connection);
    }
}

I also use a trait for ease of use in other classes. The main function is runQuery(), and it's the one I've spent most time developing.

I want to know how to make it perform better / more secure.

Answer 1

About code-style: all classes/traits/interfaces must be Capitalized.

Some notes:

• What do you mean writing database? Connection? Query? Don't mix them.
• Models can't contain any methods with side-effects(like output), remember it!
• Don't create superClassThatDoesAllTheWorkForTheApplication it's awful, also this is antipattern. Split tasks as it's shown in first paragraph.
• Don't use getError method! Just throw an exception!
• Don't use Reflection if you don't really need them! They are very slow.
• Don't use for loop where you can use foreach. foreach is faster!

• Never write code like this in construct method:

  if($db->connect_errno > 0) {return false;} You have exceptions for this!

• Never write just wrappers for ready functional! If you write database abstraction do it in abstract way and firstly write interfaces. Code is always secondary