i have start working with CodeIgniter, but i can't understand one think. How do i load one class into another?
$this->load->library("hello_world");
This is not working?
my class -> load -> hello_world class
class myclass {
function test() {
$this->load->library("hello_world");
$this->hello_world->hello();
}
}
Message: Undefined property: myclass::$load
The ability to load a class depends on the load->library function being available. It is made available to the controller and model classes, but extending these may not be appropriate for your use.
Instead you can either get a reference to CI and use that to load and refer to your class, or you can load it as usual in PHP ($c = new MyClass).
To get a rerence to CI use the following:
$CI =& get_instance();
$CI->load->helper('url');
$CI->load->library('session');
$CI->config->item('base_url');
etc.
You have to extend the CI controller/model
e.g.
class Some_controller extends Controller
{
public function index() {}
}
Related
Why do I need to use the parent::__construct(); constructor, what does it have I need?
//CONTROLLER
class users_ctrl extends CI_Controller {
function __construct() {
parent::__construct(); //Why do I need to include it?
$this->load->model('select_model');
}
public function index()
{
$data['user_list'] = $this->select_model->get_all_users();
$this->load->view('show_users', $data);
}
}
//MODEL
class select_model extends CI_Model{
function __construct() {
parent::__construct();
}
function get_all_users()
{
$query = $this->db->get('students');
return $query->result();
}
}
In your given examples, you are calling the load class that the base controller class loads. Without the parent's constructor, you would have to load an instance of it yourself.
As for your model, you would have to manually load your db object.
Remove it and you should get something like called to undefined propery $class::load
CodeIgniter aside, it really is a basic fundamental of object-oriented programming.
If you make a class that extends another, and you declare a new constructor in the child class, the parent constructor will never run - since you've overridden it, and since CodeIgniter base controller does (most likely) a lot of things behind the scenes, if you do not run parent constructor, your controller most likely won't be injected in CI's container.
$this is use for current class and view is method but what is load. Is this a property?
Is this example correct?
class super{
public $property;
public function superf1()
{
echo "hello";
}
public function col()
{
$this->superf1();
}
$this->property->super1();
}
Yes, load is a property.
Think of it like this:
class Loader {
public function view() {
//code...
}
}
class MyClass {
private $load;
public __constructor() {
$this->load = new Loader();
}
public someMethod() {
$this->load->view();
}
}
This syntax is called chaining.
Your controller inherits CI_Controller. So, if you look in application/system/core/Controller.php you'll find something interesting : $this->load =& load_class('Loader', 'core'); (l.50 with CI2). So, $this->load refer to the file application/system/core/Loader.php which have a function public function view (l.418 with CI2)
In the context of a class that extends CI_Controller (in other words: a controller) the symbol $this is the Codeigniter "super object". Which is, more or less, the central object for CI sites and contains (among other things) a list of loaded classes. load is one of the classes you'll always find there because it is automatically loaded by the CI system.
Technically, the class creates objects of the type CI_Loader. view() is just one of the many methods in the load class. Other commonly used class methods are model(), library(), config(), helper(), and database(). There are others.
So, in short, load is a class used to load other resources.
load is a class belongs to the loader class
codeigniter official documentation
view, model and others are methods
In PHP 8.1
use return("viewname", $data)
So for example, i want to access config on CI from my class library.
Class A {
funcion x() {
$this->config->load('my_config'); // accessing my_config
}
}
that obviously won't work unless you extends and then call parent::__construct().
As far as i know, it can only be done from classes that extend CI_Controller or CI_Model. How to access CI stuff (config, helper, model, etc) on non-CI class ?
Thanks.
How about initiating the class from the construct?
include ("CI_Page.php");
class A {
protected $_CIInstance1;
protected $_CIInstance2;
public function __construct(){
$this->_CIInstance1 = new xxxx();
$this->_CIInstance2 = new yyyy();
}
public function x(){
$this->_CIInstance1->load('my_config');
}
}
You probably want to access the instance of CI as if it were the super variable, $this. In reality what you need is the ability to access the same functionality as $this and in order to do this, you'll need to use $CI =& get_instance();
You can find it directly in the documentation for Creating Libraries
I have been using CI for two years now. One thing that really annoys me is the use of &get_instance(). Although it is halpful while we are inside library , helper , presenters , model etc. But everytime loading it is cumborsome. If you forget loading it somewhere and simply use $this->blah->blah() instead of $CI->blah->blah() this makes too much trouble and if you are working online you face the client who is complaining that he sees the error. I have seen in the laravel that you does not need to load the instance anywhere throughout the application. This is because laravel is autoloading all the libraries and models and both are available anywhere in the application. But this seems to me disadvantage why loading classes that are not required in some particular places. This tells me Codeigniter is flexible but still i want an alternative where i dont want to use &get_instance(). Any idea or suggestion ? Please.
In your model or Core model or library
//class MY_Model extends CI_Model
//class SomeLibrary
class Some_model extends CI_Model {
private $_CI;
public function __construct() {
parent::__construct(); //for model or core model
$this->_CI =& get_instance();
}
//if you called attributs who does not exist in that class or parent class
public function __get($key)
{
return $this->_CI->$key;
}
//if you called methods who does not exist in that class or parent class
public function __call($method, $arguments)
{
call_user_func_array(array($this->_CI, $method), $arguments );
}
public function test() {
var_dump($this->some_controller_key);
var_dump($this->some_lib_loaded);
}
}
*NOT TESTED YET
Inspired by an piece of code from the awesome Flexi Auth
//from a Model to keep access of CI_Controller attributs
public function &__get($key)
{
$CI =& get_instance();
return $CI->$key;
}
I was shocked when I saw that ^^
To explain the &__get, i think when you will call this magic method a second time PHP will do not execute it again, but will take his result from the first call.
So I'm trying to extend the input library (CI 2.1.1), and when I call my custom save query function, its saying the function doesn't exist.
File: MY_Input.php, in the applications/libraries folder:_
class MY_Input extends CI_Input {
var $CI;
function __construct() {
parent::__construct();
$this->CI =& get_instance();
}
function save_query($query_array) {
$this->CI->db->insert('ci_query', array('query_string' => http_build_query($query_array)));
}
}
And in the controller I'm calling the function like this
$query_id = $this->input->save_query($query_array);
So what on earth am I doing wrong that it's giving me this error:_
Fatal error: Call to undefined method CI_Input::save_query() in ....
Can't see why it's not working, I even checked the user guide and according to it I guess I'm doing it right. :/
The CI_Input class is a core library (new thing in CI2.0.0). You will have to put your MY_Input.php file under application/core/ to make the framework pick it up.
When in doubt, look for the original class under system/core or system/libraries and mirror it under application/.