Controllers in CodeIgniter

Overview

• Tutorial by Alex from Alex Lansford.
• Focus on understanding controllers in CodeIgniter.

Definition of Controllers

• A controller is a class file associated with a URI (Uniform Resource Identifier).
• Example: In a home controller (home.php), accessed via localhost/home.
• Default controller is loaded when no specific URL is provided.

Creating a New Controller

1. Duplicate home.php: Rename to shop.php and change class name to Shop.
2. Naming Convention: First letter uppercase, rest lowercase.
3. Update View: Change view from welcome page to shop.
4. Create View File: views/shop.php with content <h2>This is a shop</h2>.

Accessing the Controller

• Navigate to localhost/shop to see the shop page.

Methods in Controllers

• Each controller can contain methods that can be accessed via the URI.
• Example: Create method product in Shop controller:
  • Access: localhost/shop/product
  • Create view file product.php with content <h2>This is a product</h2>.

Dynamic Product Access

• Allow dynamic access to products via URI parameters:
  • Change method to accept parameters and echo them:

    echo '<h2>This is a product ' . $type . '</h2>';
    

• Example: Access localhost/shop/product/laptop shows "This is a product laptop".

Protected Methods

• Use protected for methods that shouldn't be publicly accessible:
  • Example: protected function admin() will give a 404 error when accessed directly.

Organizing Controllers

1. Create Admin Folder: Inside controllers, create admin folder.
2. Duplicate Shop: Copy shop.php into admin folder, rename as Shop.php.
3. Update Namespace: Ensure the namespace reflects the folder structure:
   • Use statement for base controller must reflect its location.

Testing Admin Controller

• Access localhost/admin/shop to check if it works.
• Change content to indicate it's the admin area:
  • Example output: <h2>This is an admin shop area</h2>.

Using Namespaces

• Allow use of controllers in different namespaces without conflicts:
  • Example: Use both Shop and Admin\\Shop in the same controller.
• Add Use Statements: Handle namespaces to avoid class name conflicts:

  use App\Controllers\Admin\Shop;
  

Practical Example

• Create instances of both shop classes in the Home controller:
  • Handle them using different names to avoid conflicts:

  $shop = new Shop();
  $adminShop = new AdminShop();
  

Conclusion

• Understanding of controllers, methods, and namespaces is crucial for CodeIgniter development.
• Next tutorial will cover routing and creating dynamic URLs.