Can you access a model from inside another model in CodeIgniter?

Question

I am writing a webapp using CodeIgniter that requires authentication. I created a model which handles all my authentication. However, I can't find a way to access this authentication model from inside another model.

Is there a way to access a model from inside another model?

or

Is there a better way to handle authentication inside CodeIgniter?

Answer 1

In general, you don't want to create objects inside an object. That's a bad habit, instead, write a clear API and inject a model into your model.

<?php
// in your controller
$model1 = new Model1();
$model2 = new Model2();
$model2->setWhatever($model1);
?>

Answer 2

Don't handle authentication in your model. Only use models to interface with your database, or ldap or whatever.

I created an Auth library that I use to manage authentication and authorization. You can access a library like this from your controllers.

Answer 3

It seems you can load models inside models, although you probably should solve this another way. See CodeIgniter forums for a discussion.

class SomeModel extends Model
{
  function doSomething($foo)
  {
    $CI =& get_instance();
    $CI->load->model('SomeOtherModel','NiceName',true);

    // use $CI instead of $this to query the other models
    $CI->NiceName->doSomethingElse();
  }
}

Also, I don't understand what Till is saying about that you shouldn't create objects inside objects. Of course you should! Sending objects as arguments looks much less clear to me.

Answer 4

I disagree about handling authorization in the controller. I handle all my authorization in my model; typically I handle it in the database. If they aren't authorized, it looks just like it doesn't exist in the database.

As for dependency injection, it does make testing much easier. I wouldn't say never create an object in another object, after all some languages only have objects. Like everything, its a trade-off, so I think its more important that you consider your situation and what will serve you best in that instance.

If they're objects who classes you are responsible for and thus you need to test independently, then dependency injection can help. It also can help if you think you might change implementations; perhaps if you are running an e-commerce site and you switch from PayPal to Authorize.net