Converting from CodeIgniter 1.7.3 to 2.0+

Question

Hello and thanks for reading.

I'll get straight to the point: I have a website project that I've been building using CodeIgniter 1.7.3, which I have thoroughly enjoyed using, however I have been contemplating upgrading to CI 2.0+.

I tried a straight copy, just moved my folders for controllers, models and views over to a CI 2.0 framework, but I got a 500 server error when I tried to view my pages.

After doing some investigation I discovered that all of your controllers must now use "CI_Controller" as their parent class. Also I noticed that if you want to include a constructor in your controller class that it must use the syntax "function __construct()" as its name and of the parent class. It seems that CI 2.0+ no longer supports using a constructor that has the same name as the class name, e.g. "class Blogs extends CI_controller{ function Blogs(){parent::__construct();}}" is no longer supported? I've been reading the CI Change Log, but all I see are bug fixes, and new features, nothing about compatibility issues with older versions of CI? Does anyone else know of any other secret little pitfalls?

Thanks,

H

Answer 1

CI 2.x removed all compatibility with PHP4 and also updated a number of standards to be compliant with PHP 5.3 going forward. One of these is the constructor issue you have encountered. As of PHP 5.3, the function ClassName() is no longer the constructor for a class, it is simply another function. You must explicitly declare a __construct function to perform any tasks that need to be done when a new instance of the class is created. Given this, you should see it no longer makes sense to call parent::ClassName() in your child constructor as that function would no longer be the parent's constructor.

Another pitfall I recently had to work out is how the $_GET array is now handled. In the 1.x versions, you could use query strings to pass back extra information and still use URI segments to route to controllers and functions. This is especially useful for AJAX calls where you may not always know all the parameters being sent to and from the server in a particular request. In the 2.x versions, the config.php file contains a new option, $config['allow_get_array']. This must be set to TRUE if you want to use query strings otherwise the input class clears out the $_GET array as part of CI's initialization routine on each request.

Something which isn't a pitfall but you may find useful is the new options in config/autoload.php that allows you to add new application directories to your project. If you work on a number of different projects with CI and want to keep any useful libraries you write in a single location, you can now add that location to $autoload['packages']. CI expects any path in this array to contain the sub-directories "controllers", "models", "libraries" and "helpers". It won't complain if you don't have those directories but you will at least need them for anything you intend to load, i.e. libraries would live in /libraries as with the main application folder.

Answer 2

Have you read the official guide for upgrading from 1.7.x to 2.x ?

so in short

• Update Models and Controllers to extend CI_Model and CI_Controller

• Update Parent Constructor calls

  class Wow extends CI_Controller {

        function __construct()
        {
            parent::__construct();
                      //your stuff
        }
  
        function index()
        {
                 // just for example 
        }
      }