How to load a controller from another controller in codeigniter?

Question 1

You can't load a controller from a controller in CI - unless you use HMVC or something.

You should think about your architecture a bit. If you need to call a controller method from another controller, then you should probably abstract that code out to a helper or library and call it from both controllers.

UPDATE

After reading your question again, I realize that your end goal is not necessarily HMVC, but URI manipulation. Correct me if I'm wrong, but it seems like you're trying to accomplish URLs with the first section being the method name and leave out the controller name altogether.

If this is the case, you'd get a cleaner solution by getting creative with your routes.

For a really basic example, say you have two controllers, controller1 and controller2. Controller1 has a method method_1 - and controller2 has a method method_2.

You can set up routes like this:

$route['method_1'] = "controller1/method_1";
$route['method_2'] = "controller2/method_2";

Then, you can call method 1 with a URL like http://site.com/method_1 and method 2 with http://site.com/method_2.

Albeit, this is a hard-coded, very basic, example - but it could get you to where you need to be if all you need to do is remove the controller from the URL.

You could also go with remapping your controllers.

From the docs: "If your controller contains a function named _remap(), it will always get called regardless of what your URI contains.":

public function _remap($method)
{
    if ($method == 'some_method')
    {
        $this->$method();
    }
    else
    {
        $this->default_method();
    }
}

Question 2

yes you can (for version 2)

load like this inside your controller

 $this->load->library('../controllers/whathever');

and call the following method:

$this->whathever->functioname();

Question 3

you cannot call a controller method from another controller directly

my solution is to use inheritances and extend your controller from the library controller

class Controller1 extends CI_Controller {

    public function index() {
        // some codes here
    }

    public function methodA(){
        // code here
    }
}

in your controller we call it Mycontoller it will extends Controller1

include_once (dirname(__FILE__) . "/controller1.php");

class Mycontroller extends Controller1 {

    public function __construct() {
        parent::__construct();
    }

    public function methodB(){
        // codes....
    }
}

and you can call methodA from mycontroller

http://example.com/mycontroller/methodA

http://example.com/mycontroller/methodB

this solution worked for me

Question 4

I had a similar problem. I wanted to have two controllers:

homepage.php - public facing homepage

home.php - home screen once a user was logged in

and I wanted them both to read from 'mydomain.com'

I was able to accomplish this by setting 'hompepage' as the default controller in my routes config and adding a remap function to homepage.php

function _remap()
{
  if(user_is_logged_in())
  {
    require_once(APPPATH.'controllers/home.php'); 
    $oHome =  new Home();
    $oHome->index();
  }
  else
  {
    $this->index();
  }
}

Question 5

I was having session file not found error while tried various ways, finally achieved like this. Made the function as static (which I want to call in the another controller), and called like

require_once('Welcome.php');
Welcome::hello();

Question 6

While the methods above might work, here is a very good method.

Extend the core controller with a MY controller, then extend this MY controller for all your other controllers. For example, you could have:

class MY_Controller extends CI_Controller {
    public function is_logged()
    {
        //Your code here
    }
public function logout()
    {
        //Your code here
    }
}

Then your other controllers could then extend this as follows:

class Another_Controller extends MY_Controller {
    public function show_home()
    {
         if (!$this->is_logged()) {
           return false;
         }
    }
public function logout()
    {
        $this->logout();
    }
}

Question 7

There are many ways by which you can access one controller into another.

class Test1 extends CI_controller
{
    function testfunction(){
        return 1;
    }
}

Then create another class, and include first Class in it, and extend it with your class.

include 'Test1.php';

class Test extends Test1
{
    function myfunction(){
        $this->test();
        echo 1;
    }
}

Question 8

I came here because I needed to create a {{ render() }} function in Twig, to simulate Symfony2's behaviour. Rendering controllers from view is really cool to display independant widgets or ajax-reloadable stuffs.

Even if you're not a Twig user, you can still take this helper and use it as you want in your views to render a controller, using <?php echo twig_render('welcome/index', $param1, $param2, $_); ?>. This will echo everything your controller outputted.

Here it is:

helpers/twig_helper.php

<?php

if (!function_exists('twig_render'))
{

    function twig_render()
    {
        $args = func_get_args();
        $route = array_shift($args);
        $controller = APPPATH . 'controllers/' . substr($route, 0, strrpos($route, '/'));

        $explode = explode('/', $route);
        if (count($explode) < 2)
        {
            show_error("twig_render: A twig route is made from format: path/to/controller/action.");
        }

        if (!is_file($controller . '.php'))
        {
            show_error("twig_render: Controller not found: {$controller}");
        }
        if (!is_readable($controller . '.php'))
        {
            show_error("twig_render: Controller not readable: {$controller}");
        }
        require_once($controller . '.php');

        $class = ucfirst(reset(array_slice($explode, count($explode) - 2, 1)));
        if (!class_exists($class))
        {
            show_error("twig_render: Controller file exists, but class not found inside: {$class}");
        }

        $object = new $class();
        if (!($object instanceof CI_Controller))
        {
            show_error("twig_render: Class {$class} is not an instance of CI_Controller");
        }

        $method = $explode[count($explode) - 1];
        if (!method_exists($object, $method))
        {
            show_error("twig_render: Controller method not found: {$method}");
        }

        if (!is_callable(array($object, $method)))
        {
            show_error("twig_render: Controller method not visible: {$method}");
        }

        call_user_func_array(array($object, $method), $args);

        $ci = &get_instance();
        return $ci->output->get_output();
    }

}

Specific for Twig users (adapt this code to your Twig implementation):

libraries/Twig.php

$this->_twig_env->addFunction('render', new Twig_Function_Function('twig_render'));

Usage

{{ render('welcome/index', param1, param2, ...) }}

Question 9

Create a helper using the code I created belows and name it controller_helper.php.

Autoload your helper in the autoload.php file under config.

From your method call controller('name') to load the controller.

Note that name is the filename of the controller.

This method will append '_controller' to your controller 'name'. To call a method in the controller just run $this->name_controller->method(); after you load the controller as described above.

<?php

if(!function_exists('controller'))
{
    function controller($name)
    {
        $filename = realpath(__dir__ . '/../controllers/'.$name.'.php');

        if(file_exists($filename))
        {
            require_once $filename;

            $class = ucfirst($name);

            if(class_exists($class))
            {
                $ci =& get_instance();

                if(!isset($ci->{$name.'_controller'}))
                {
                    $ci->{$name.'_controller'} = new $class();
                }
            }
        }
    }
}
?>