1. In Model: catalog/model/account/api.php --> function login()

public function login($username, $key) { ********$query = $this->db->query("SELECT * FROM `" . DB_PREFIX . "api` WHERE `username` = '" . $this->db->escape($username) . "' `key` = '" . $this->db->escape($key) . "' AND status = '1'"); ********return $query->row; ****}
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public function login($username, $key) { ********$query = $this->db->query("SELECT * FROM `" . DB_PREFIX . "api` WHERE `username` = '" . $this->db->escape($username) . "' AND `key` = '" . $this->db->escape($key) . "' AND status = '1'"); ********return $query->row; ****}

• In Controller: catalog/controller/api/login.php

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$session = new Session($config->get('session_engine'), $registry);
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$session = new Session($this->config->get('session_engine'), $this->registry);